Updated .gitignore

CHANGELOG.md

@@ -0,0 +1,144 @@
+# SLS Changelog
+
+## 0.0.2-alpha
+*08 Dec 2025*
+
+- Added Rust Port
+- Added Interpreter State Serialization to Rust port
+    - Added `#load <file>` and `#save <file>` directives to the REPL
+- Added Python Port
+- Added Calculator app
+    - Added sls_py.calc module
+- Added RP2040 build target for the C implementation
+
+## 0.0.1-alpha
+*01 Dec 2025*
+
+- Added executing a file
+- Implemented the following builtin operators:
+    - `for`
+    - `logb`
+    - `max`
+    - `min`
+    - `rot`
+    - `const`
+    - `atan2`
+    - `roll`
+    - `while`
+    - `type_of`
+    - `eval`
+    - `lambda`
+    - `if`
+    - `pick`
+    - `dup`
+    - bitwise `and`
+    - bitwise `not`
+    - bitwise `or`
+    - bitwise `xor`
+    - boolean `and`
+    - boolean `not`
+    - boolean `or`
+    - `shl`
+    - `shr`
+    - comparisons
+    - `ceil`
+    - `floor`
+    - `round`
+    - `swap`
+    - `seed`
+    - `rand`
+    - `acos`
+    - `asin`
+    - `atan`
+    - `cos`
+    - `ln`
+    - `log`
+    - `sin`
+    - `sqrt`
+    - `tan`
+    - `abs`
+    - modulus
+    - exponential
+    - addition
+    - subtraction
+    - multiplication
+
+## SE Checkpoint 3
+*28 Nov 2025*
+
+[github.com/SnowSE/final-project-KylerOlsen](https://github.com/SnowSE/final-project-KylerOlsen)
+
+[Compare SE3250-Checkpoint2..SE3250-Checkpoint3](https://github.com/SnowSE/final-project-KylerOlsen/compare/SE3250-Checkpoint2...SE3250-Checkpoint3)
+
+**Report**:
+
+Since checkpoint 2, I completed `token string` parsing and started working on
+the REPL. The lexer and REPL are basically finished as much as I am going to do
+for this assignment. I did start to implement builtin functions and operators.
+Currently only
+[`depth`](https://sls.purplecello.org/complete_operator_reference.html#depth),
+[`drop`](https://sls.purplecello.org/complete_operator_reference.html#drop), and
+[`/`](https://sls.purplecello.org/complete_operator_reference.html#_5)
+
+**Plan**:
+
+By the final turn-in on December 6th, I plan on getting all arithmetic
+operations working. And the python and rust ports with help from AI.
+
+**Stuck**:
+
+I'm not really stuck on anything, but I am running out of time, plus I am
+worried about not having enough AI usage to do the ports. If I at least get the
+main structures of the ports, I hope it will be enough for me to finish.
+
+## SE Checkpoint 2
+*20 Nov 2025*
+
+[github.com/SnowSE/final-project-KylerOlsen](https://github.com/SnowSE/final-project-KylerOlsen)
+
+[Compare SE3250-Checkpoint1..SE3250-Checkpoint2](https://github.com/SnowSE/final-project-KylerOlsen/compare/SE3250-Checkpoint1...SE3250-Checkpoint2)
+
+**Report**:
+
+I completed my string type for the interpreter. `floats`, `characters`,
+`identifiers`, and `boolean` token lexing has been completed. `integer` tokens
+were working at checkpoint 1.
+
+**Plan**:
+
+By checkpoint 3 I plan to complete `token string` token parsing and basic
+arithmetic execution.
+
+**Stuck**:
+
+I'm not really stuck on anything, but I have been dropping things from the scope
+of this assignment. I do hope to add them when I have time in the future. These
+features moved to the backlog include:
+
+- Unicode support
+- Exponential literals
+- Arrays and array functions
+- Type tuples, function defs
+- Structs, unions, etc.
+
+## SE Checkpoint 1
+*07 Nov 2025*
+
+**intended user**:  
+Programmers
+
+**detailed functional requirements**:  
+A stack based language interpreter inspired by RPL, C, Rust, and Uiua
+([sls.purplecello.org](https://sls.purplecello.org))
+
+**motivation for wanting to work on the project**:  
+It is cool, and I have had this idea for a while and learning new languages this
+semester has given me more ideas and motivation for this.
+
+**motivation for language selection**:  
+C is a lower level language that can run on embedded systems and is well suited
+for writing language interpreters like Python and Lua.
+
+**non-functional requirements / constraints**:  
+Efficient enough for use on a modern micro controller
+(ie. Raspberry Pi Pico, ESP32)

PROGRESS.md

@@ -1,53 +0,0 @@
-# SE 3250 Progress Checkpoints
-
-## Checkpoint 1
-*07 Nov 2025*
-
-**intended user**:  
-Programmers
-
-**detailed functional requirements**:  
-A stack based language interpreter inspired by RPL, C, Rust, and Uiua
-([sls.purplecello.org](https://sls.purplecello.org))
-
-**motivation for wanting to work on the project**:  
-It is cool, and I have had this idea for a while and learning new languages this
-semester has given me more ideas and motivation for this.
-
-**motivation for language selection**:  
-C is a lower level language that can run on embedded systems and is well suited
-for writing language interpreters like Python and Lua.
-
-**non-functional requirements / constraints**:  
-Efficient enough for use on a modern micro controller
-(ie. Raspberry Pi Pico, ESP32)
-
-## Checkpoint 2
-*20 Nov 2025*
-
-[github.com/SnowSE/final-project-KylerOlsen](https://github.com/SnowSE/final-project-KylerOlsen)
-
-[Compare SE3250-Checkpoint1..SE3250-Checkpoint2](https://github.com/SnowSE/final-project-KylerOlsen/compare/SE3250-Checkpoint1...SE3250-Checkpoint2)
-
-**Report**:
-
-I completed my string type for the interpreter. `floats`, `characters`,
-`identifiers`, and `boolean` token lexing has been completed. `integer` tokens
-were working at checkpoint 1.
-
-**Plan**:
-
-By checkpoint 3 I plan to complete `token string` token parsing and basic
-arithmetic execution.
-
-**Stuck**:
-
-I'm not really stuck on anything, but I have been dropping things from the scope
-of this assignment. I do hope to add them when I have time in the future. These
-features moved to the backlog include:
-
-- Unicode support
-- Exponential literals
-- Arrays and array functions
-- Type tuples, function defs
-- Structs, unions, etc.

README.md

@@ -1,97 +1,128 @@
 # YREA SLS
 *Kyler Olsen*  
 *October 2025*
-*Snow College*  
-*SE 3250 Survey of Languages Final Project*
 
-Language Code Name: YREA **SLS** (*Stack Language Specification*)  
-Language Specifications: [sls.purplecello.org](https://sls.purplecello.org)  
-Language Specification Repository (Private): [git.purplecello.org](https://git.purplecello.org/KylerOlsen/LangsFinalPlaning)  
-Language Implementation Repository (Private): [git.purplecello.org](https://git.purplecello.org/KylerOlsen/YREA-SLS)  
-Language Implementation Repository (Mirror on GitHub) (Private): [github.com](https://github.com/SnowSE/final-project-KylerOlsen)  
-Assignment Page (Private): [snow.instructure.com](https://snow.instructure.com/courses/1154808/assignments/16233203)
+SLS is a statically-typed, stack-based language with pure postfix notation
+combining the execution model of HP's RPL, the type system of C and Rust, and
+modern array operations from Uiua.
 
-## Assignment Description
+## Build Commands
 
-**Overview**
+**Linux**
 
-In your final project for this course, you will do the following:
+C
+```bash
+cd SLS_C
+python3 build.py build
+./bin/sls
+```
 
-- Decide on a modest personal project to complete in a new-to-you
-programming language (during class time, we will randomize the list of
-people in the class and allow languages to be selected uniquely on a
-first-come, first-served basis; be prepared to pick the language you want
-and to advocate for the languages that you don't want).
-- Without using AI generated or suggested code, complete your project in
-your assigned language including automated testing. Find a way to make your
-useful implementation concise and elegant enough that you would be able to
-recreate it reasonably quickly without AI assistance (be prepared to
-demonstrate this ability during a one-on-one interview to ensure credit).
-- Using AI help as desired, create a faithful port of your implementation
-(including tests) to:
-    - Rust
-    - Python
-    - Java (optional, but it might be interesting and userful for your
-    resume)
-    - C# (optional, but it might be interesting)
-    - typescript (optional, but it might be interesting)
-- For each ported implementation, add one addition feature (not present in
-the original or other ports).
-- Prepare a report that describes:
-    - the problem that your project solves and why you are interested in it
-    - a brief description of how the language that you chose and the port
-    languages were or were not each a good fit for the project
-    - three examples of ideas you learned in the course that you leveraged
-    to the implementation in your assigned language elegant, efficient, and
-    concise/maintainable (at least one idea should specifically come from
-    functional programming) -- make sure to be specific and teach the reader
-    something valuable for each of these
-    - at least one struggle that you faced (or that you imagine that others
-    would likely face) for each language implementation, and what you
-    learned from working with the port languages during the porting process.
-- Prepare slides that help you teach the key ideas from your report to the
-class.
-- In a 5-8 minute presentation during the final exam slot, use your slides
-to teach the class and demonstrate your running project including the
-addition port features.
+Python run module
+```bash
+cd SLS_Python
+python3 -m sls_py
+python3 -m sls_py.calc
+```
 
-Project Scope
+Python Setup
+```bash
+cd SLS_Python
+python -m venv .venv
+source .venv/bin/activate
+pip install build wheel "setuptools>=61.0"
+pip install -e sls_build_backend
+```
 
-- Please do something that will be fun and interesting for you!
-- Make sure that the project actually solves a problem that you care about.
-(Entertainment counts, but if that is the problem you care about, then make
-sure that you can make something that actually is entertaining!)
-- I'm expecting you to dedicate about 15-30 hours to the entire project
-(including all three implementations and the report/presentation
-preparation). I'm expecting that your initial implmentation should feel
-like about twice the scope of implementing the game of life in PostScript
-or K.
+Python build module
+```bash
+cd SLS_Python
+source .venv/bin/activate
+python3 -m build --no-isolation
+pip install ./dist/sls_python-0.0.2a0-py3-none-any.whl
+python3 -m sls_py
+python3 -m sls_py.calc
+```
 
-**Languages**
+Rust
+```bash
+cd SLS_Rust/sls
+cargo build
+./target/debug/sls_rs
+```
 
-For what it is worth, here are a few resources that rank or compare different
-programming languages in terms of popularity or jobs (but they don't equally
-capture how programming in the languages will give you tools for thinking
-about and solving problems):
+**Windows**
 
-- https://spectrum.ieee.org/top-programming-languages-2025 
-- https://www.tiobe.com/tiobe-index/
-- https://survey.stackoverflow.co/2025/technology#admired-and-desired
-- https://survey.stackoverflow.co/2025/technology#most-popular-technologies-language-prof
-- https://tjpalmer.github.io/languish/
-- https://www.geeksforgeeks.org/blogs/top-programming-languages/
-- https://github.com/breck7/pldb
+C (Using Visual Studio Developer PowerShell)
+```shell
+cd SLS_C
+python build.py build
+.\bin\sls.exe
+```
 
-Here is the list of programming languages that you will be able to choose from
-for your initial implementation (each language will be chosen by at most one
-student; we will choose during class time on Oct 27):
+Python run module
+```bat
+cd SLS_Python
+python -m sls_py
+python -m sls_py.calc
+```
 
-- **C** Kyler
+Python Setup
+```bat
+cd SLS_Python
+python -m venv .venv
+.venv\Scripts\activate.bat
+pip install build wheel "setuptools>=61.0"
+pip install -e sls_build_backend
+```
 
-**Submission**
+Python build module
+```bat
+cd SLS_Python
+.venv\Scripts\activate.bat
+python -m build --no-isolation
+pip install .\dist\sls_python-0.0.2a0-py3-none-any.whl
+python -m sls_py
+python -m sls_py.calc
+```
 
-Submit all material (including report and slides) via github classrooms repo.
-Also, submit your github repo link and the path to the report and slides file
-in the canvas text box for this assignment. The grace period for submission
-ends at 3pm on Monday, Dec 8. Presentations will be 3:30pm - 5:30pm. For full
-credit, you must present and watch the presentations of your classmates.
+Rust
+```bat
+cd SLS_Rust\sls
+cargo build
+.\target\debug\sls_rs.exe
+```
+
+**MacOS**
+
+Reference Linux build instructions.
+
+For C there is the `python3 build.py macos` command, but it is untested as I
+didn't test it on a Mac. I also don't know if `python3 build.py build` would also
+work on a Mac.
+
+Python and Rust should just be the same or similar to Linux.
+
+**RP2040**
+
+Only tested on Linux. Only SLS_C supports RP2040.
+
+Install Pico SDK to `~/pico/pico-sdk`, or set environment variable
+`PICO_SDK_PATH` to your installation path. You will also need to install the
+appropriate compiler.
+
+Debian GNU/Linux
+```bash
+sudo apt install gcc-arm-none-eabi
+```
+
+```shell
+cd SLS_C
+python3 build.py rp2040
+```
+
+Flash Raspberry Pi Pico:  
+Copy `.\build_pico\sls.elf.uf2` to your Pico in BOOTSEL mode
+
+## Contributing
+
+[sls.purplecello.org/contributing](https://sls.purplecello.org/contributing.html)

REPORT.md

@@ -0,0 +1,92 @@
+# YREA SLS
+*Kyler Olsen*  
+*October-December 2025*  
+*Snow College*  
+*SE 3250*  
+*Survey of Languages*  
+*Final Project*
+
+Language Code Name:
+YREA **SLS** (*Stack Language Specification*)  
+Language Webpage:
+[sls.purplecello.org](https://sls.purplecello.org)  
+Language Specification Repository (Private):
+[git.purplecello.org](https://git.purplecello.org/KylerOlsen/LangsFinalPlaning)  
+Language Implementation Repository:
+[git.purplecello.org](https://git.purplecello.org/KylerOlsen/YREA-SLS)  
+Language Implementation Repository (Mirror on GitHub) (Private):
+[github.com](https://github.com/SnowSE/final-project-KylerOlsen)  
+Assignment Page (Private):
+[snow.instructure.com](https://snow.instructure.com/courses/1154808/assignments/16233203)
+
+In 1986, Hewlett-Packard released their HP-18C and HP-24C calculators, which
+introduced their new RPL operating system and programming language. The language
+was based on LISP and Forth (a stack-oriented language). RPL, aka Reverse Polish
+Lisp, was used by HP in several of their calculators through the 1990s and
+2000s, most famously on the HP-48 series of calculators. HP calculators have
+been a favorite among engineers because of their post-fix notation.
+
+When in my journeyings on the internet a few years ago, I discovered Uiua, a
+pre-fix, stack-based, array-oriented language, which inspired me to create my
+own, except more largely inspired by HP's RPL. I started planning out an idea,
+but never made it far. This semester I was again inspired by looking at the
+various programming languages to again make my own, this time throwing in C to
+the mix. What resulted is my *Stack Language Specification*. Having difficulty
+coming up with a name for the language, I went with SLS.
+
+SLS is a stack-oriented language with C inspired syntax. While these have not
+been implemented for the assignment, I do plan on adding a Rust inspired type
+system, as well as Uiua and LISP inspired array operations. Memory management
+follows the pattern in RPL, everything is on the stack. One of my goals with
+this language is also to have it able to run on an embedded system, such as my
+own custom calculator.
+
+**C** was my selected language. It was an excellent choice for my project as it
+is well suited for systems programming. It is a low level, yet powerful
+language. While string utilities are not as robust as most modern languages, I
+still feel like it was an excellent choice. Other major interpreted languages
+also use C to implement their interpreters, such as Lua and Python.
+
+Manual memory management was a slight difficulty for me. The only way I could
+find what was causing a segmentation fault was to run the binary with `gdb`.
+Still my experience programming C in a Linux environment was fun and rewarding.
+I became accustomed to utilizing the man pages (or manual pages) for
+documentation on the C standard library.
+
+I did use structs and unions heavily which we learned about when we looked at C.
+With them I was able to use polymorphism in defining tokens and data types.
+
+I am able to successfully compile and run this implementation on a Raspberry Pi
+Pico with a RP2040 microcontroller. You can interact with the REPL over a serial
+connection.
+
+**Rust** was the first language I tackled porting my project to. I am not as
+familiar with Rust as I am Python, so thats why I wanted to get going on this
+port first. I avoided using external libraries with C as they can be famously
+difficult to link and compile. Rust's build system, cargo made that issue
+basically non-existent. It is also memory safe with its barrow checker. With it
+being another systems programming language, and these modern features, I feel
+like it is just as good of a choice of a language for my project.
+
+In the past I have often fought with the barrow checker but with this project,
+either my experience, memory mindfulness in my original port, or the extensive
+AI help, I had no fights with the barrow checker this time.
+
+The special feature for the Rust port is being able to export and import the
+interpreter state in the repl using `#save <filename>` and `#load <filename>`.
+
+**Python** was my final port. With it being the language I am most comfortable
+and experienced with, this was an easy port to make. While it is very easy, even
+for someone without my experience, and it has many of the same modern
+conveniences with package management as Rust. Where it is not a systems
+programming language, I would not be able to run this project on an embedded
+system very cleanly or easily, making Python not as good of a choice with my
+goal of portability to embedded systems.
+
+The special feature for the Python port is the SLS Calculator App.
+
+---
+
+https://en.wikipedia.org/wiki/HP_48_series
+https://en.wikipedia.org/wiki/HP-28_series
+https://en.wikipedia.org/wiki/RPL_(programming_language)

SLS_C/.gitignore

@@ -1,3 +1,9 @@
 obj/
 bin/
+build_pico/
 *.o
+*.pdb
+CMakeLists.txt
+pico_arm_gcc_toolchain.cmake
+generated/
+pico-sdk.txt

SLS_C/Failing Tests.md

@@ -0,0 +1,60 @@
+# Failing Tests
+
+These tests fail and haven't been fixed yet as they would likely take major
+refactoring to fix, which I may not have time to do before finals week.
+
+## Integer i64 Overflow
+code: `9223372036854775808:i64`  
+error: `Integer overflow: value exceeds range for i64.`
+
+This test fails because the parsed integer has already overflowed inside the
+interpreter, so an integer token is returned with no overflow error detected.
+
+## Integer i64 Underflow
+code: `-9223372036854775809:i64`  
+error: `Integer overflow: value exceeds range for i64.`
+
+This test fails because the parsed integer has already overflowed inside the
+interpreter, so an integer token is returned with no overflow error detected.
+
+## Integer u64 Overflow
+code: `18446744073709551616:u64`  
+error: `Integer overflow: value exceeds range for u64.`
+
+This test fails because the parsed integer has already overflowed inside the
+interpreter, so an integer token is returned with no overflow error detected.
+
+## Integer i16 Binary Sample
+code: `0b1111111100000000:i16`  
+value: `-256`
+
+This test fails because the interpreter fails to recognize this as a negative
+number, and parses is as `65280`, which is greater than the signed 16-bit max of
+`32767`, resulting in an overflow error.
+
+## Float Default No Leading Digit Negative
+code: `-.25`  
+value: `-0.25`
+
+This test fails because the interpreter fails to recognize a token starting with
+both a `-` then a `.` then a digit, as a numeric literal, resulting in it being
+interpreted as an identifier.
+
+## TokenString Error Inside
+code: `{ 2 3a + }`  
+error: `Invalid decimal literal: unexpected 'a' in decimal integer.`
+
+I don't know why this test is being reported as failing. I think it may be
+trying looking for the error inside the token string.
+
+## TokenString Struct Fields
+code: `{ x: y: }`  
+value: `TokenString`
+
+All non-code token strings won't work properly unless they are also valid code
+token strings. All non-code token string features won't be implemented yet.
+
+## Windows Tests
+
+`test_format_basic_placeholders` and `Integer i32 Min Value` also fail when
+compiling with MSVC on Windows instead of GCC on Linux.

SLS_C/Makefile

@@ -1,77 +0,0 @@
-# Makefile for SLS project with automatic header dependencies
-
-CC ?= gcc
-CFLAGS ?= -std=c99 -Wall -Wextra -g -Iinclude -MMD -MP
-LDFLAGS ?=
-CTESTFLAGS ?= -std=c99 -Wall -Wextra -Wno-unused-function -g -O0 -Iinclude -MMD -MP
-
-SRCDIR := src
-OBJDIR := obj
-BINDIR := bin
-TESTDIR := tests
-
-TARGET := $(BINDIR)/sls
-TEST_TARGET := $(BINDIR)/sls_tests
-
-SOURCES := $(wildcard $(SRCDIR)/*.c)
-OBJECTS := $(patsubst $(SRCDIR)/%.c,$(OBJDIR)/%.o,$(SOURCES))
-NON_MAIN_OBJECTS := $(filter-out $(OBJDIR)/main.o,$(OBJECTS))
-
-TEST_SOURCES := $(wildcard $(TESTDIR)/*.c)
-TEST_OBJECTS := $(patsubst $(TESTDIR)/%.c,$(OBJDIR)/%.o,$(TEST_SOURCES))
-
-# Include dependency files if they exist
--include $(OBJECTS:.o=.d) $(TEST_OBJECTS:.o=.d)
-
-.PHONY: all build run test clean
-
-# Default: build main program
-all: $(TARGET)
-
-# Compile object files
-build: $(OBJECTS)
-
-# Rule to compile .c -> .o (handles both src and tests)
-$(OBJDIR)/%.o: $(SRCDIR)/%.c | $(OBJDIR)
-	$(CC) $(CFLAGS) -c $< -o $@
-
-$(OBJDIR)/%.o: $(TESTDIR)/%.c | $(OBJDIR)
-	$(CC) $(CTESTFLAGS) -c $< -o $@
-
-# Link main program
-$(TARGET): $(OBJECTS) | $(BINDIR)
-	$(CC) $(LDFLAGS) $^ -o $@ -lm
-
-# Run main program
-run: $(TARGET)
-	@echo "Running $(TARGET)..."
-	./$(TARGET)
-
-test_cases: ../SLS_Tests/yaml_to_c_tests.py ../SLS_Tests/cases.yaml
-	python3 ../SLS_Tests/yaml_to_c_tests.py ../SLS_Tests/cases.yaml ./tests/lexer_tests.c
-
-# Build test runner executable
-$(TEST_TARGET): $(TEST_OBJECTS) $(NON_MAIN_OBJECTS) | $(BINDIR)
-	$(CC) $(LDFLAGS) $^ -o $@ -lm
-
-build_tests: test_cases $(TEST_TARGET)
-
-# Run tests
-debug: build_tests
-	gdb ./$(TEST_TARGET)
-
-# Run tests
-test: test_cases $(TEST_TARGET)
-	@echo "Running tests..."
-	./$(TEST_TARGET)
-
-# Create directories if missing
-$(BINDIR):
-	mkdir -p $(BINDIR)
-
-$(OBJDIR):
-	mkdir -p $(OBJDIR)
-
-# Remove build artifacts
-clean:
-	rm -rf $(OBJDIR) $(BINDIR)

SLS_C/README.md

@@ -2,10 +2,22 @@
 
 This is the C implementation for the YREA SLS interpreter.
 
-## Running
+## Compiling, Running, and Testing
 
-Build Project: `make build`  
-Build and Run Project: `make run`  
-Build and Run Tests: `make test`
+Interpreter binary location:
+- Linux: `./bin/sls`
+- Windows: `.\bin\sls.exe`
 
-Interpreter binary location: `./bin/sls`
+### Linux (GCC)
+
+Build Project: `python3 build.py all`  
+Build and Run Project: `python3 build.py run`  
+Build and Run Tests: `python3 build.py test`
+
+### Windows (MSVC)
+
+*__For Windows users:__ Use a VS developer shell for all build commands.*
+
+Build Project: `python build.py all`  
+Build and Run Project: `python build.py run`  
+Build and Run Tests: `python build.py test`

SLS_C/build.py

@@ -0,0 +1,515 @@
+#!/usr/bin/env python3
+import os
+import sys
+import subprocess
+from pathlib import Path
+import shutil
+import platform
+
+# ---------------------------------------------------------------------
+# CONFIG
+# ---------------------------------------------------------------------
+SRC_DIR = Path("src")
+TEST_DIR = Path("tests")
+OBJ_DIR = Path("obj")
+BIN_DIR = Path("bin")
+
+TARGET = BIN_DIR / "sls"
+TEST_TARGET = BIN_DIR / "sls_tests"
+
+# Platform-specific settings
+PICO_SDK_PATH = os.environ.get("PICO_SDK_PATH", Path.home() / "pico/pico-sdk")
+PICO_BUILD_DIR = Path("build_pico")
+PICO_TOOLCHAIN_PATH = Path("pico_arm_gcc_toolchain.cmake")
+
+# Unix gcc/clang flags
+COMMON_FLAGS = ["-std=c99", "-Wall", "-Wextra", "-Werror", "-Iinclude", "-g"]
+TEST_FLAGS = ["-std=c99", "-Wall", "-Wextra", "-Wno-unused-function", "-Werror",
+              "-Iinclude", "-g", "-O0"]
+
+# macOS-specific flags (for cross-compilation if needed)
+MACOS_FLAGS = ["-std=c99", "-Wall", "-Wextra", "-Werror", "-Iinclude", "-g",
+               "-mmacosx-version-min=10.13"]
+
+# Windows MSVC flags
+MSVC_FLAGS = ["/std:c11", "/Zi", "/Iinclude"]
+MSVC_TEST_FLAGS = MSVC_FLAGS + []
+
+# RP2040 toolchain file template
+PICO_TOOLCHAIN_TEMPLATE = """set(CMAKE_SYSTEM_NAME Generic)
+set(CMAKE_SYSTEM_PROCESSOR cortex-m0plus)
+
+# Specify the cross compiler
+set(CMAKE_C_COMPILER arm-none-eabi-gcc)
+set(CMAKE_CXX_COMPILER arm-none-eabi-g++)
+set(CMAKE_ASM_COMPILER arm-none-eabi-gcc)
+
+# Compiler flags for Cortex-M0+
+set(CMAKE_C_FLAGS_INIT "-mcpu=cortex-m0plus -mthumb")
+set(CMAKE_CXX_FLAGS_INIT "-mcpu=cortex-m0plus -mthumb")
+set(CMAKE_ASM_FLAGS_INIT "-mcpu=cortex-m0plus -mthumb")
+
+# Don't run the linker on compiler check
+set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+
+# Adjust the default behavior of the FIND_XXX() commands:
+# search programs in the host environment
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+# Search headers and libraries in the target environment
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+"""
+
+# RP2040 settings
+RP2040_CMAKE_TEMPLATE = """cmake_minimum_required(VERSION 3.13)
+
+# Pico SDK initialization
+set(PICO_SDK_PATH "{pico_sdk_path}")
+include({pico_sdk_path}/external/pico_sdk_import.cmake)
+
+project({project_name} C CXX ASM)
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+
+pico_sdk_init()
+
+# Main executable
+add_executable({project_name}
+{source_files}
+)
+
+# Set output name with .elf extension
+set_target_properties({project_name} PROPERTIES
+    OUTPUT_NAME "{project_name}.elf"
+    SUFFIX ""
+)
+
+# Add include directories
+target_include_directories({project_name} PRIVATE
+    ${{CMAKE_CURRENT_LIST_DIR}}/include
+)
+
+# Add compile definitions
+target_compile_definitions({project_name} PRIVATE
+    PICO_BUILD=1
+    GIT_COMMIT_HASH="{git_hash}"
+)
+
+# Link libraries
+target_link_libraries({project_name}
+    pico_stdlib
+    hardware_uart
+    hardware_gpio
+)
+
+# Enable USB/UART output
+pico_enable_stdio_usb({project_name} 1)
+pico_enable_stdio_uart({project_name} 1)
+
+# Create map/bin/hex/uf2 files
+pico_add_extra_outputs({project_name})
+"""
+
+# ---------------------------------------------------------------------
+# PLATFORM DETECTION
+# ---------------------------------------------------------------------
+def detect_platform():
+    """Detect the current operating system"""
+    system = platform.system()
+    if system == "Darwin":
+        return "macos"
+    elif system == "Windows":
+        return "windows"
+    elif system == "Linux":
+        return "linux"
+    return "unknown"
+
+PLATFORM = detect_platform()
+
+# ---------------------------------------------------------------------
+# COMPILER DETECTION
+# ---------------------------------------------------------------------
+def detect_compiler(target_platform=None):
+    """Detect appropriate compiler for the target platform"""
+    if target_platform == "rp2040":
+        return ("arm-none-eabi-gcc", "gcc")
+    
+    target = target_platform or PLATFORM
+    
+    if target == "windows" or os.name == "nt":
+        return ("cl", "msvc")
+    elif target == "macos":
+        # Prefer clang on macOS
+        if shutil.which("clang"):
+            return ("clang", "gcc")
+        return ("gcc", "gcc")
+    else:
+        return ("gcc", "gcc")
+
+CC, CC_KIND = detect_compiler()
+
+# ---------------------------------------------------------------------
+# PYTHON DETECTION
+# ---------------------------------------------------------------------
+def detect_python():
+    if os.name == "nt":
+        return "python"
+    return "python3"
+
+PYTHON = detect_python()
+
+
+# ---------------------------------------------------------------------
+# GIT COMMIT HASH
+# ---------------------------------------------------------------------
+def git_commit_hash():
+    try:
+        result_hash = subprocess.check_output(
+            ["git", "describe", "--always", "--dirty", "--abbrev=7"],
+            cwd=".",
+            stderr=subprocess.DEVNULL,
+            text=True
+        ).strip()
+        result_date = subprocess.check_output(
+            ["git", "show", "-s", "--format=%ci"],
+            cwd=".",
+            stderr=subprocess.DEVNULL,
+            text=True
+        ).strip()
+        return f"{result_hash} {result_date}"
+    except Exception:
+        return "unknown"
+
+
+GIT_HASH = git_commit_hash()
+
+
+# ---------------------------------------------------------------------
+# UTILS
+# ---------------------------------------------------------------------
+def mkdir(p: Path):
+    p.mkdir(parents=True, exist_ok=True)
+
+
+def run(cmd):
+    print(">>", " ".join(str(c) for c in cmd))
+    subprocess.check_call(cmd)
+
+
+def is_up_to_date(src, obj, dep):
+    if "meta" in [src.stem, obj.stem, dep.stem]:
+        return False
+    if not obj.exists():
+        return False
+    if dep.exists() and dep.stat().st_mtime > obj.stat().st_mtime:
+        return False
+    return src.stat().st_mtime < obj.stat().st_mtime
+
+
+# ---------------------------------------------------------------------
+# BUILD RULES
+# ---------------------------------------------------------------------
+def compile_source(src: Path, is_test=False, target_platform=None):
+    mkdir(OBJ_DIR)
+    obj = OBJ_DIR / (src.stem + ".o")
+    dep = OBJ_DIR / (src.stem + ".d")
+
+    if is_up_to_date(src, obj, dep):
+        return obj
+
+    compiler, kind = detect_compiler(target_platform)
+    
+    if kind == "msvc":
+        flags = MSVC_TEST_FLAGS if is_test else MSVC_FLAGS
+        cmd = [compiler] + flags + ["/Fo" + str(obj), "/c", str(src),
+                               f"/DGIT_COMMIT_HASH=\"{GIT_HASH}\""]
+    else:
+        if target_platform == "macos":
+            flags = MACOS_FLAGS if not is_test else TEST_FLAGS + ["-mmacosx-version-min=10.13"]
+        else:
+            flags = TEST_FLAGS if is_test else COMMON_FLAGS
+            
+        cmd = [compiler] + flags + [
+            f"-DGIT_COMMIT_HASH=\"{GIT_HASH}\"",
+            "-MMD", "-MP",
+            "-c", str(src), "-o", str(obj)
+        ]
+
+    run(cmd)
+    return obj
+
+
+def link_executable(objects, output: Path, target_platform=None):
+    mkdir(BIN_DIR)
+    compiler, kind = detect_compiler(target_platform)
+    
+    if kind == "msvc":
+        cmd = [compiler] + list(map(str, objects)) + ["/Fe" + str(output)]
+    else:
+        cmd = [compiler] + list(map(str, objects)) + ["-lm", "-o", str(output)]
+    run(cmd)
+
+
+# ---------------------------------------------------------------------
+# TEST CASE GENERATION
+# ---------------------------------------------------------------------
+def generate_tests():
+    script = Path("../SLS_Tests/yaml_to_c_tests.py")
+    yaml = Path("../SLS_Tests/cases.yaml")
+    out = TEST_DIR / "lexer_tests.c"
+
+    if not script.exists() or not yaml.exists():
+        print("Test generation skipped (missing files).")
+        return False
+
+    if out.exists() and out.stat().st_mtime > yaml.stat().st_mtime:
+        return True
+
+    run([PYTHON, str(script), str(yaml), str(out)])
+    return True
+
+
+# ---------------------------------------------------------------------
+# RP2040 BUILD
+# ---------------------------------------------------------------------
+def check_pico_sdk():
+    """Check if Pico SDK is available"""
+    sdk_path = Path(PICO_SDK_PATH)
+    if not sdk_path.exists():
+        print(f"ERROR: Pico SDK not found at {sdk_path}")
+        print("Please set PICO_SDK_PATH environment variable or install SDK at ~/pico/pico-sdk")
+        return False
+    
+    # Check for ARM toolchain
+    if not shutil.which("arm-none-eabi-gcc"):
+        print("ERROR: ARM toolchain not found!")
+        print("Please install arm-none-eabi-gcc:")
+        print("  Ubuntu/Debian: sudo apt install gcc-arm-none-eabi")
+        print("  macOS: brew install arm-none-eabi-gcc")
+        return False
+    
+    return True
+
+
+def generate_pico_toolchain():
+    """Generate ARM GCC toolchain file for CMake"""
+    with open(PICO_TOOLCHAIN_PATH, "w") as f:
+        f.write(PICO_TOOLCHAIN_TEMPLATE)
+    print(f"Generated {PICO_TOOLCHAIN_PATH}")
+
+
+def generate_pico_cmake(project_name="sls"):
+    """Generate CMakeLists.txt for RP2040 build"""
+    sources = list(SRC_DIR.glob("*.c"))
+    # Exclude main.c, repl.c, file.c and test files for Pico build
+    # pico_main.c will provide its own REPL implementation
+    sources = [s for s in sources 
+               if s.name not in ["main.c", "repl.c", "file.c"] 
+               and "test" not in s.stem.lower()]
+    
+    # Check for pico_main.c
+    pico_main = SRC_DIR / "pico_main.c"
+    if not pico_main.exists():
+        print(f"WARNING: {pico_main} not found! Please create it.")
+        print("The Pico build requires a pico_main.c file.")
+        return False
+    
+    sources.append(pico_main)
+    
+    source_files = "\n".join(f"    {s}" for s in sources)
+    
+    cmake_content = RP2040_CMAKE_TEMPLATE.format(
+        project_name=project_name,
+        source_files=source_files,
+        git_hash=GIT_HASH,
+        pico_sdk_path=PICO_SDK_PATH
+    )
+    
+    cmake_file = Path("CMakeLists.txt")
+    with open(cmake_file, "w") as f:
+        f.write(cmake_content)
+    
+    print(f"Generated {cmake_file}")
+    return True
+
+
+def build_rp2040():
+    """Build for RP2040 using CMake"""
+    if not check_pico_sdk():
+        return False
+    
+    print("\n=== Building for RP2040 ===\n")
+    
+    # Generate toolchain file
+    generate_pico_toolchain()
+    
+    # Generate CMakeLists.txt
+    if not generate_pico_cmake():
+        return False
+    
+    # Create build directory
+    mkdir(PICO_BUILD_DIR)
+    
+    # Run CMake with explicit toolchain
+    cmake_cmd = [
+        "cmake",
+        "-B", str(PICO_BUILD_DIR),
+        "-S", ".",
+        f"-DCMAKE_TOOLCHAIN_FILE={PICO_TOOLCHAIN_PATH}"
+    ]
+    run(cmake_cmd)
+    
+    # Build
+    build_cmd = ["cmake", "--build", str(PICO_BUILD_DIR), "-j4"]
+    run(build_cmd)
+    
+    # Show output files
+    uf2_file = PICO_BUILD_DIR / "sls.uf2"
+    if uf2_file.exists():
+        print(f"\nBuild successful! UF2 file: {uf2_file}")
+        print("To flash: Copy this file to your Pico in BOOTSEL mode")
+    
+    return True
+
+
+# ---------------------------------------------------------------------
+# MACOS BUILD
+# ---------------------------------------------------------------------
+def build_macos():
+    """Build for macOS (can be run on macOS or cross-compile on Linux)"""
+    print("\n=== Building for macOS ===\n")
+    
+    if PLATFORM != "macos" and PLATFORM != "linux":
+        print("ERROR: macOS builds require macOS or Linux with osxcross")
+        return False
+    
+    sources = list(SRC_DIR.glob("*.c"))
+    objects = [compile_source(s, is_test=False, target_platform="macos") for s in sources]
+    
+    macos_target = BIN_DIR / "sls_macos"
+    link_executable(objects, macos_target, target_platform="macos")
+    
+    print(f"\nBuild successful! Binary: {macos_target}")
+    return True
+
+
+# ---------------------------------------------------------------------
+# TARGETS
+# ---------------------------------------------------------------------
+def build_main():
+    sources = list(SRC_DIR.glob("*.c"))
+    objects = [compile_source(s, is_test=False) for s in sources if s.name != 'pico_main.c']
+    link_executable(objects, TARGET)
+
+
+def build_tests():
+    generate_tests()
+    test_sources = list(TEST_DIR.glob("*.c"))
+    main_sources = [s for s in SRC_DIR.glob("*.c") if s.name != "main.c"]
+
+    test_objects = [compile_source(s, is_test=True) for s in test_sources]
+    shared_objects = [compile_source(s, is_test=False) for s in main_sources]
+
+    link_executable(test_objects + shared_objects, TEST_TARGET)
+
+
+def clean():
+    shutil.rmtree(OBJ_DIR, ignore_errors=True)
+    shutil.rmtree(BIN_DIR, ignore_errors=True)
+    shutil.rmtree(PICO_BUILD_DIR, ignore_errors=True)
+    cmake_file = Path("CMakeLists.txt")
+    if cmake_file.exists():
+        cmake_file.unlink()
+    toolchain_file = PICO_TOOLCHAIN_PATH
+    if toolchain_file.exists():
+        toolchain_file.unlink()
+    print("Cleaned.")
+
+
+def run_main():
+    build_main()
+    print("\n--- Running program ---\n")
+    subprocess.call([str(TARGET)])
+
+
+def run_tests():
+    build_tests()
+    print("\n--- Running tests ---\n")
+    subprocess.call([str(TEST_TARGET)])
+
+
+def debug_tests():
+    build_tests()
+    if os.name == "nt":
+        print("Debugging on Windows requires Visual Studio debugger.")
+    else:
+        subprocess.call(["gdb", str(TEST_TARGET)])
+
+
+def show_help():
+    help_text = """
+Build Script for Multi-Platform Compilation
+============================================
+
+Usage: python3 build.py [command]
+
+Commands:
+  all, main, build    Build for current platform
+  run                 Build and run program
+  test                Build and run tests
+  debug               Build tests and run debugger
+  clean               Remove build artifacts
+  
+  macos               Build for macOS
+  pico, rp2040        Build for RP2040 (Raspberry Pi Pico)
+  
+  help                Show this help message
+
+Environment Variables:
+  PICO_SDK_PATH       Path to Pico SDK (default: ~/pico/pico-sdk)
+
+Examples:
+  python3 build.py build      # Build for current platform
+  python3 build.py pico       # Build for RP2040
+  python3 build.py macos      # Build for macOS
+  python3 build.py clean      # Clean all build files
+"""
+    print(help_text)
+
+
+# ---------------------------------------------------------------------
+# ENTRY POINT
+# ---------------------------------------------------------------------
+def main():
+    if len(sys.argv) < 2:
+        show_help()
+        return
+
+    cmd = sys.argv[1]
+
+    match cmd:
+        case "all" | "main" | "build":
+            build_main()
+        case "run":
+            run_main()
+        case "test":
+            run_tests()
+        case "debug":
+            debug_tests()
+        case "clean":
+            clean()
+        case "macos":
+            build_macos()
+        case "pico" | "rp2040":
+            build_rp2040()
+        case "help" | "-h" | "--help":
+            show_help()
+        case _:
+            print(f"Unknown target: {cmd}")
+            print("Run 'python3 build.py help' for usage information")
+
+
+if __name__ == "__main__":
+    main()

SLS_C/fib.min.sls

@@ -0,0 +1 @@
+{ 2 - dup 0 <= { drop 1 } { 1 1 rot 0 swap { drop swap 1 pick + } for swap drop } if } lambda ::fib const

SLS_C/fib.sls

@@ -0,0 +1,17 @@
+{
+	// Start with which Fibonacci number we want (Nth Fibonacci number)
+	2 - // We push the first two already
+	dup 0 <= { drop 1 } {
+		1 1 // Starting Fibonacci numbers
+		rot 0 swap // Setting up loop from zero to N
+		{
+			drop // Discard the loop counter
+			swap 1 pick // Swap n-1 and n-2 and copy n-1
+			+ // Add n-2 and the copy of n-1
+			// n and n-1 left on stack
+		} for
+		swap drop // Drop n-1 from the stack
+	} if
+} lambda ::fib const
+
+8 fib

SLS_C/include/sls/builtin.h

@@ -0,0 +1,31 @@
+// Kyler Olsen
+// YREA SLS
+// Builtin Functions Header
+// November 2025
+
+#ifndef SLS_BUILTIN_FUNCTIONS_H
+#define SLS_BUILTIN_FUNCTIONS_H
+
+#include "sls/bool.h"
+#include "sls/interpreter.h"
+
+#if __SIZEOF_POINTER__ == 4
+    // 32-bit system
+    #define SLS_INTEGER_BUILTIN_DEFAULT INTEGER_I32
+    #define SLS_UNSIGNED_INTEGER_BUILTIN_DEFAULT INTEGER_U32
+    #define SLS_FLOAT_BUILTIN_DEFAULT TOKEN_FLOAT
+#elif __SIZEOF_POINTER__ == 8
+    // 64-bit system
+    #define SLS_INTEGER_BUILTIN_DEFAULT INTEGER_I64
+    #define SLS_UNSIGNED_INTEGER_BUILTIN_DEFAULT INTEGER_U64
+    #define SLS_FLOAT_BUILTIN_DEFAULT TOKEN_DOUBLE
+#else
+    // Fallback
+    #define SLS_INTEGER_BUILTIN_DEFAULT INTEGER_I16
+    #define SLS_UNSIGNED_INTEGER_BUILTIN_DEFAULT INTEGER_U16
+    #define SLS_FLOAT_BUILTIN_DEFAULT TOKEN_FLOAT
+#endif
+
+Boolean load_builtins(InterpreterState *interpreter_state);
+
+#endif // SLS_BUILTIN_FUNCTIONS_H

SLS_C/include/sls/file.h

@@ -0,0 +1,16 @@
+// Kyler Olsen
+// YREA SLS
+// File Header
+// November 2025
+
+#ifndef SLS_FILE_H
+#define SLS_FILE_H
+
+#include "sls/bool.h"
+#include "sls/string.h"
+#include "sls/interpreter.h"
+
+Boolean exec_file(InterpreterState *interpreter_state, SlsStr filename);
+int file(SlsStr filename);
+
+#endif // SLS_FILE_H

SLS_C/include/sls/hash_table.h

@@ -0,0 +1,37 @@
+// Kyler Olsen
+// YREA SLS
+// Hash Table Header
+// November 2025
+
+#ifndef SLS_HASH_TABLE_H
+#define SLS_HASH_TABLE_H
+
+#include <stddef.h>
+
+#include "sls/string.h"
+
+typedef struct Bucket {
+    uint32_t hash_a;
+    uint32_t hash_b;
+    void *item;
+    struct Bucket *next;
+} Bucket;
+
+typedef struct {
+    size_t buckets_count;
+    Bucket *buckets[];
+} HashTable;
+
+// Initializes a HashTable with atleast buckets_count number of buckets. Returns NULL on Memory Allocation Error.
+HashTable *init_hash_table(size_t min_buckets_count);
+// Frees memory owned by the HashTable.
+void del_hash_table(HashTable *ht);
+
+// Inserts an item into the HashTable based on its key. Returns FALSE on Memory Allocation Error.
+Boolean hash_table_put(HashTable *ht, SlsStr key, void *item);
+// Gets the item associated with the given key. Returns default item if not found.
+void *hash_table_get(const HashTable *ht, SlsStr key, void *default_item);
+// Deletes the item associated with the given key. Returns FALSE if item is not found.
+Boolean hash_table_del(HashTable *ht, SlsStr key);
+
+#endif // SLS_HASH_TABLE_H

SLS_C/include/sls/interpreter.h

@@ -0,0 +1,85 @@
+// Kyler Olsen
+// YREA SLS
+// Interpreter Header
+// November 2025
+
+#ifndef SLS_INTERPRETER_H
+#define SLS_INTERPRETER_H
+
+#include <stddef.h>
+
+#include "sls/bool.h"
+#include "sls/lexer.h"
+#include "sls/hash_table.h"
+
+typedef enum {
+    STACK_IDENTIFIER,
+    STACK_I64,
+    STACK_I32,
+    STACK_I16,
+    STACK_I8,
+    STACK_U64,
+    STACK_U32,
+    STACK_U16,
+    STACK_U8,
+    STACK_FLOAT,
+    STACK_DOUBLE,
+    STACK_CHARACTER,
+    STACK_BOOLEAN,
+    STACK_TOKEN_STRING,
+    STACK_CALLABLE,
+} StackType;
+
+extern const char *STACK_TYPES_NAMES[];
+extern const char *STACK_TYPES_TYPES[];
+extern const size_t STACK_TYPE_COUNT;
+
+typedef struct StackItem {
+    StackType type;
+    union {
+        Identifier identifier; // type == STACK_IDENTIFIER
+        int64_t i64; // type == STACK_I64
+        int32_t i32; // type == STACK_I32
+        int16_t i16; // type == STACK_I16
+        int8_t i8; // type == STACK_I8
+        uint64_t u64; // type == STACK_U64
+        uint32_t u32; // type == STACK_U32
+        uint16_t u16; // type == STACK_U16
+        uint8_t u8; // type == STACK_U8
+        float f32; // type == STACK_FLOAT
+        double f64; // type == STACK_DOUBLE
+        uint8_t character; // type == STACK_CHARACTER
+        Boolean boolean; // type == STACK_BOOLEAN
+        TokenString token_string; // type == STACK_TOKEN_STRING
+    };
+    struct StackItem *next;
+} StackItem;
+
+typedef struct {
+    StackItem *stack;
+    HashTable *functions;
+} InterpreterState;
+
+typedef enum {
+    FUNCTION_TOKEN_STRING,
+    FUNCTION_BUILTIN,
+} FunctionType;
+
+typedef struct {
+    FunctionType type;
+    union {
+        TokenString token_string; // type == FUNCTION_TOKEN_STRING
+        Boolean (*builtin)(InterpreterState *); // type == FUNCTION_BUILTIN
+    };
+} FunctionItem;
+
+Boolean push_token(InterpreterState *interpreter_state, Token token);
+void clean_stack(StackItem *item);
+
+Boolean execute_func(InterpreterState *interpreter_state, SlsStr key);
+Boolean execute_token_string(InterpreterState *interpreter_state, TokenString token_string);
+Boolean execute(InterpreterState *interpreter_state, LexerTokenResult *token);
+InterpreterState *interpreter_create();
+void interpreter_delete(InterpreterState *interpreter_state);
+
+#endif // SLS_INTERPRETER_H

SLS_C/include/sls/lexer.h

@@ -11,6 +11,20 @@
 #include "sls/bool.h"
 #include "sls/errors.h"
 
+#if __SIZEOF_POINTER__ == 4
+    // 32-bit system
+    #define SLS_INTEGER_TYPE_DEFAULT INTEGER_I32
+    #define SLS_FLOAT_TYPE_DEFAULT NUMERIC_F32
+#elif __SIZEOF_POINTER__ == 8
+    // 64-bit system
+    #define SLS_INTEGER_TYPE_DEFAULT INTEGER_I64
+    #define SLS_FLOAT_TYPE_DEFAULT NUMERIC_F64
+#else
+    // Fallback
+    #define SLS_INTEGER_TYPE_DEFAULT INTEGER_I16
+    #define SLS_FLOAT_TYPE_DEFAULT NUMERIC_F32
+#endif
+
 extern const size_t TYPE_NAMES_SAFE_LENGTH;
 
 typedef struct {
@@ -36,6 +50,7 @@ typedef enum {
 } TokenType;
 
 extern const char *TOKEN_TYPES_NAMES[];
+extern const size_t TOKEN_TYPE_COUNT;
 
 typedef enum {
     ARRAY_IDENTIFIER,
@@ -56,6 +71,7 @@ typedef enum {
 } ArrayType;
 
 extern const char *ARRAY_TYPES_NAMES[];
+extern const size_t ARRAY_TYPE_COUNT;
 
 typedef struct {
     SlsStr name;
@@ -74,6 +90,7 @@ typedef enum {
 } IntegerBuiltInType;
 
 extern const char *INTEGER_TYPES_NAMES[];
+extern const size_t INTEGER_TYPE_COUNT;
 
 typedef struct {
     uint64_t value;
@@ -151,8 +168,10 @@ typedef struct {
     };
 } LexerResult;
 
+TokenString copy_token_string(TokenString token_string);
 void init_lexer(LexerInfo *lexer_info, SlsStr filename, SlsStr source_code);
 LexerTokenResult *get_token(LexerTokenResult *head, size_t i);
+void clean_token_string(TokenString token_string);
 void clean_token_result(LexerTokenResult *head);
 LexerResult lexical_analysis(LexerInfo *lexer_info);
 

SLS_C/include/sls/meta.h

@@ -0,0 +1,35 @@
+// Kyler Olsen
+// YREA SLS
+// Main Header
+// November 2025
+
+#ifndef SLS_MAIN_H
+#define SLS_MAIN_H
+
+#define SLS_NAME "SLS_C"
+#define SLS_VER "0.0.2-alpha"
+
+#ifndef GIT_COMMIT_HASH
+    #define GIT_COMMIT_HASH "UNKNOWN"
+#endif
+
+#if defined(__GNUC__)
+    #define COMPILER_NAME "GCC"
+    #define COMPILER_VER __GNUC__
+
+#elif defined(__clang__)
+    #define COMPILER_NAME "Clang"
+    #define COMPILER_VER __clang_major__
+
+#elif defined(_MSC_VER)
+    #define COMPILER_NAME "MSVC"
+    #define COMPILER_VER _MSC_VER
+
+#else
+    #define COMPILER_NAME "Unknown compiler"
+    #define COMPILER_VER 0
+#endif
+
+void print_version();
+
+#endif // SLS_MAIN_H

SLS_C/include/sls/repl.h

@@ -0,0 +1,11 @@
+// Kyler Olsen
+// YREA SLS
+// REPL Header
+// November 2025
+
+#ifndef SLS_REPL_H
+#define SLS_REPL_H
+
+int repl();
+
+#endif // SLS_REPL_H

SLS_C/include/sls/string.h

@@ -18,8 +18,10 @@ typedef struct {
     Boolean allocated;
 } SlsStr;
 
-#define SLS_STR(s) (SlsStr){ sizeof(s) - 1, (s), FALSE }
-#define SLS_STR_NULL (SlsStr){0, NULL, FALSE}
+#define SLS_STR_CONST(s) {sizeof(s) - 1, (s), FALSE}
+#define SLS_STR_NULL_CONST {0, NULL, FALSE}
+#define SLS_STR(s) (SlsStr) SLS_STR_CONST(s)
+#define SLS_STR_NULL (SlsStr) SLS_STR_NULL_CONST
 
 int sls_isascii(unsigned char c);
 size_t sls_str_nlen(const char *s, size_t maxlen);

SLS_C/include/tests/lexer_test_helpers.h

@@ -124,6 +124,6 @@ Boolean test_array_boolean_value(LexerTest *test, LexerResult result, size_t i,
 Boolean test_array_struct_inline_value(LexerTest *test, LexerResult result, size_t i, TestArrayStructInlineValue *values);
 Boolean test_token_string_value(LexerTest *test, LexerResult result, size_t i, TestTokenStringValue *values);
 Boolean test_type_tuple_value(LexerTest *test, LexerResult result, size_t i, TestTypeTupleValue *values);
-Boolean test_for_error(LexerTest *test, LexerResult result, size_t i, SlsStr error);
+Boolean test_for_error(LexerTest *test, LexerResult result, size_t i, SlsStr *error);
 
 #endif // SLS_LEXER_TEST_HELPERS_H

SLS_C/include/tests/tests.h

@@ -39,6 +39,7 @@ typedef struct {
 
 TestsReport run_string_tests();
 TestsReport run_lexer_tests();
+TestsReport run_hash_table_tests();
 TestsReport run_extra_tests();
 
 #endif // SLS_TESTS_H

SLS_C/src/file.c

@@ -0,0 +1,68 @@
+// Kyler Olsen
+// YREA SLS
+// File
+// November 2025
+
+#include <stdio.h>
+
+#include "sls/file.h"
+#include "sls/bool.h"
+#include "sls/string.h"
+#include "sls/interpreter.h"
+
+Boolean exec_file(InterpreterState *interpreter_state, SlsStr filename) {
+    FILE *file_o = fopen(filename.str, "r");
+    if (file_o == NULL) {
+        printf("Cannot read file: %s\n", filename.str);
+        return FALSE;
+    }
+
+    if (fseek(file_o, 0, SEEK_END)) return FALSE;
+    size_t file_length = ftell(file_o);
+    rewind(file_o);
+
+    LexerInfo lexer_info;
+    SlsStr code = sls_str_new(file_length);
+    for (size_t i = 0; i < file_length; i++) {
+        int character = fgetc(file_o);
+        if (character == EOF) return FALSE;
+        else code.str[i] = (char)character;
+    }
+    init_lexer(&lexer_info, filename, code);
+
+    LexerResult result = lexical_analysis(&lexer_info);
+    if (result.type == SLS_ERROR) {
+        printf("%s\n", result.error.message.str);
+        sls_str_free(&result.error.message);
+        return FALSE;
+    } else {
+        LexerTokenResult *head = result.result;
+        while (head) {
+            if (head->type == SLS_ERROR) {
+                printf("%s\n", head->error.message.str);
+                sls_str_free(&result.error.message);
+                clean_token_result(result.result);
+                return FALSE;
+            } else if (!execute(interpreter_state, head)) {
+                printf("A runtime error occurred!\n");
+                break;
+            }
+            head = head->next;
+        }
+        clean_token_result(result.result);
+    }
+    sls_str_free(&code);
+
+    if (fclose(file_o)) return FALSE;
+    else return TRUE;
+}
+
+int file(SlsStr filename) {
+    printf("Executing file: %s\n", filename.str);
+    InterpreterState *interpreter_state = interpreter_create();
+    if (interpreter_state == NULL) return 1;
+    Boolean success = exec_file(interpreter_state, filename);
+    interpreter_delete(interpreter_state);
+    if (success) return 0;
+    else return 1;
+}

SLS_C/src/hash_table.c

@@ -0,0 +1,155 @@
+// Kyler Olsen
+// YREA SLS
+// Hash Table
+// November 2025
+
+#include <stdlib.h>
+
+#include "sls/hash_table.h"
+#include "sls/string.h"
+
+static size_t next_power_of_two(size_t n) {
+    if (n < 2) return 2;
+    n--;
+    n |= n >> 1;
+    n |= n >> 2;
+    n |= n >> 4;
+    n |= n >> 8;
+    n |= n >> 16;
+    #if SIZE_MAX > UINT32_MAX
+        n |= n >> 32;
+    #endif
+    n++;
+    return n;
+}
+
+HashTable *init_hash_table(size_t min_buckets_count) {
+    size_t buckets_count = next_power_of_two(min_buckets_count);
+    size_t size = sizeof(HashTable) + buckets_count * sizeof(Bucket);
+    HashTable *ht = (HashTable *)malloc(size);
+    if (!ht) return NULL;
+    ht->buckets_count = buckets_count;
+    for (size_t i = 0; i < buckets_count; i++)
+        ht->buckets[i] = NULL;
+    return ht;
+}
+
+void del_hash_table(HashTable *ht) {
+    for (size_t i = 0; i < ht->buckets_count; i++) {
+        Bucket *head = ht->buckets[i];
+        while (head) {
+            Bucket *next = head->next;
+            // TODO: Does item need to be freed?
+            free(head);
+            head = next;
+        }
+    }
+    free(ht);
+}
+
+static inline uint32_t sls_hash_a(SlsStr key) {
+    // FNV-1a
+    uint32_t hash = 2166136261u;
+    const uint8_t *p = (const uint8_t *)key.str;
+    for (size_t i = 0; i < key.len; i++) {
+        hash ^= p[i];
+        hash *= 16777619u;
+    }
+    return hash;
+}
+
+static inline uint32_t sls_hash_b(SlsStr key) {
+    // Murmur2A
+    const uint32_t m = 0x5bd1e995;
+    uint32_t hash = 0;
+
+    while (key.len >= 4) {
+        uint32_t k = (uint32_t)key.str[0]
+            | (uint32_t)key.str[1] << 8
+            | (uint32_t)key.str[2] << 16
+            | (uint32_t)key.str[3] << 24;
+        k *= m;
+        k ^= k >> 24;
+        k *= m;
+
+        hash *= m;
+        hash ^= k;
+
+        key.str += 4;
+        key.len -= 4;
+    }
+
+    if (key.len >= 3)
+        hash ^= key.str[2] << 16;
+    if (key.len >= 2)
+        hash ^= key.str[1] << 8;
+    if (key.len >= 1)
+        hash ^= key.str[0];
+    hash *= m;
+
+    hash ^= hash >> 13;
+    hash *= m;
+    hash ^= hash >> 15;
+
+    return hash;
+}
+
+Boolean hash_table_put(HashTable *ht, SlsStr key, void *item) {
+    uint32_t hash_a = sls_hash_a(key);
+    uint32_t hash_b = sls_hash_b(key);
+    size_t bucket_index = hash_a & (ht->buckets_count - 1);
+
+    for (Bucket *node = ht->buckets[bucket_index]; node; node = node->next) {
+        if (node->hash_a == hash_a && node->hash_b == hash_b) {
+            // TODO: Does item need to be freed before being replaced?
+            node->item = item;
+            return TRUE;
+        }
+    }
+
+    Bucket *bucket = (Bucket *)malloc(sizeof(Bucket));
+    if (!bucket)
+        return FALSE;
+    bucket->hash_a = hash_a;
+    bucket->hash_b = hash_b;
+    bucket->item = item;
+    bucket->next = ht->buckets[bucket_index];
+    ht->buckets[bucket_index] = bucket;
+
+    return TRUE;
+}
+
+void *hash_table_get(const HashTable *ht, SlsStr key, void *default_item) {
+    uint32_t hash_a = sls_hash_a(key);
+    uint32_t hash_b = sls_hash_b(key);
+    size_t bucket_index = hash_a & (ht->buckets_count - 1);
+
+    for (Bucket *node = ht->buckets[bucket_index]; node; node = node->next)
+        if (node->hash_a == hash_a && node->hash_b == hash_b)
+            return node->item;
+
+    return default_item;
+}
+
+Boolean hash_table_del(HashTable *ht, SlsStr key) {
+    uint32_t hash_a = sls_hash_a(key);
+    uint32_t hash_b = sls_hash_b(key);
+    size_t bucket_index = hash_a & (ht->buckets_count - 1);
+
+    Bucket *prev = NULL;
+
+    for (Bucket *node = ht->buckets[bucket_index]; node; node = node->next) {
+        if (node->hash_a == hash_a && node->hash_b == hash_b) {
+            if (prev == NULL)
+                ht->buckets[bucket_index] = node->next;
+            else
+                prev->next = node->next;
+            // TODO: Does item need to be freed?
+            free(node);
+            return TRUE;
+        }
+        prev = node;
+    }
+
+    return FALSE;
+}

SLS_C/src/interpreter.c

@@ -0,0 +1,232 @@
+// Kyler Olsen
+// YREA SLS
+// Interpreter
+// November 2025
+
+#include <stdlib.h>
+
+#include "sls/string.h"
+#include "sls/interpreter.h"
+#include "sls/lexer.h"
+#include "sls/hash_table.h"
+#include "sls/builtin.h"
+
+static const size_t HASH_TABLE_BUCKET_COUNT = 256;
+
+const char *STACK_TYPES_NAMES[] = {
+    "Identifier",
+    "64-bit Integer",
+    "32-bit Integer",
+    "16-bit Integer",
+    "8-bit Integer",
+    "64-bit U Integer",
+    "32-bit U Integer",
+    "16-bit U Integer",
+    "8-bit U Integer",
+    "Float",
+    "Double",
+    "Character",
+    "Boolean",
+    "Token String",
+    "Callable",
+};
+
+const char *STACK_TYPES_TYPES[] = {
+    "Identifier",
+    "i64",
+    "i32",
+    "i16",
+    "i8",
+    "u64",
+    "u32",
+    "u16",
+    "u8",
+    "f32",
+    "f64",
+    "char",
+    "bool",
+    "TokenString",
+    "Callable",
+};
+
+const size_t STACK_TYPE_COUNT = sizeof(STACK_TYPES_NAMES) / sizeof(*STACK_TYPES_NAMES);
+
+static inline Boolean hash_table_put_funcs(HashTable *ht, SlsStr key, FunctionItem *item) {
+    return hash_table_put(ht, key, (void *)item);
+}
+
+static inline FunctionItem *hash_table_get_funcs(const HashTable *ht, SlsStr key, FunctionItem *default_item) {
+    return (FunctionItem*)hash_table_get(ht, key, (void *)default_item);
+}
+
+Boolean push_token(InterpreterState *interpreter_state, Token token) {
+    StackType type;
+    switch (token.type) {
+    case TOKEN_EOF:
+        return TRUE;
+    case TOKEN_IDENTIFIER:
+        type = STACK_IDENTIFIER;
+        break;
+    case TOKEN_INTEGER:
+        switch (token.integer_literal.type) {
+        case INTEGER_I64:
+            type = STACK_I64;
+            break;
+        case INTEGER_I32:
+            type = STACK_I32;
+            break;
+        case INTEGER_I16:
+            type = STACK_I16;
+            break;
+        case INTEGER_I8:
+            type = STACK_I8;
+            break;
+        case INTEGER_U64:
+            type = STACK_U64;
+            break;
+        case INTEGER_U32:
+            type = STACK_U32;
+            break;
+        case INTEGER_U16:
+            type = STACK_U16;
+            break;
+        case INTEGER_U8:
+            type = STACK_U8;
+            break;
+        }
+        break;
+    case TOKEN_FLOAT:
+        type = STACK_FLOAT;
+        break;
+    case TOKEN_DOUBLE:
+        type = STACK_DOUBLE;
+        break;
+    case TOKEN_CHARACTER:
+        type = STACK_CHARACTER;
+        break;
+    case TOKEN_STRING:
+        return FALSE;
+    case TOKEN_BOOLEAN:
+        type = STACK_BOOLEAN;
+        break;
+    case TOKEN_ARRAY:
+        return FALSE;
+    case TOKEN_TOKEN_STRING:
+        type = STACK_TOKEN_STRING;
+        break;
+    case TOKEN_TYPE_TUPLE:
+        return FALSE;
+    }
+
+    StackItem *item = (StackItem *)malloc(sizeof(StackItem));
+    if (item == NULL) return FALSE;
+    item->type = type;
+    item->next = interpreter_state->stack;
+    interpreter_state->stack = item;
+
+    switch (type) {
+    case STACK_IDENTIFIER:
+        item->identifier = token.identifier;
+        break;
+    case STACK_I64:
+        item->i64 = (int64_t)token.integer_literal.value;
+        break;
+    case STACK_I32:
+        item->i32 = (int32_t)token.integer_literal.value;
+        break;
+    case STACK_I16:
+        item->i16 = (int16_t)token.integer_literal.value;
+        break;
+    case STACK_I8:
+        item->i8 = (int8_t)token.integer_literal.value;
+        break;
+    case STACK_U64:
+        item->u64 = (uint64_t)token.integer_literal.value;
+        break;
+    case STACK_U32:
+        item->u32 = (uint32_t)token.integer_literal.value;
+        break;
+    case STACK_U16:
+        item->u16 = (uint16_t)token.integer_literal.value;
+        break;
+    case STACK_U8:
+        item->u8 = (uint8_t)token.integer_literal.value;
+        break;
+    case STACK_FLOAT:
+        item->f32 = token.float_literal;
+        break;
+    case STACK_DOUBLE:
+        item->f64 = token.double_literal;
+        break;
+    case STACK_CHARACTER:
+        item->character = token.character_literal;
+        break;
+    case STACK_BOOLEAN:
+        item->boolean = token.boolean_literal;
+        break;
+    case STACK_TOKEN_STRING:
+    case STACK_CALLABLE:
+        item->token_string = copy_token_string(token.token_string);
+        break;
+    }
+
+    return TRUE;
+}
+
+Boolean execute_func(InterpreterState *interpreter_state, SlsStr key) {
+    FunctionItem *func = hash_table_get_funcs(interpreter_state->functions, key, NULL);
+    if (func == NULL) return FALSE;
+    switch (func->type) {
+    case FUNCTION_BUILTIN:
+        return func->builtin(interpreter_state);
+    case FUNCTION_TOKEN_STRING:
+        return execute_token_string(interpreter_state, func->token_string);
+    }
+    return FALSE;
+}
+
+Boolean execute_token_string(InterpreterState *interpreter_state, TokenString token_string) {
+    Boolean return_value = FALSE;
+    for (size_t i = 0; i < token_string.length; i++) {
+        if (token_string.tokens[i].type == TOKEN_IDENTIFIER && !token_string.tokens[i].identifier.is_literal)
+            return_value = execute_func(interpreter_state, token_string.tokens[i].identifier.name);
+        else
+            return_value = push_token(interpreter_state, token_string.tokens[i]);
+        if (!return_value) break;
+    }
+    return return_value;
+}
+
+Boolean execute(InterpreterState *interpreter_state, LexerTokenResult *token) {
+    if (token->result.type == TOKEN_IDENTIFIER && !token->result.identifier.is_literal)
+        return execute_func(interpreter_state, token->result.identifier.name);
+    else
+        return push_token(interpreter_state, token->result);
+}
+
+InterpreterState *interpreter_create() {
+    InterpreterState *interpreter_state = (InterpreterState *)malloc(sizeof(InterpreterState));
+    if (interpreter_state == NULL)
+        return NULL;
+    interpreter_state->stack = NULL;
+    interpreter_state->functions = init_hash_table(HASH_TABLE_BUCKET_COUNT);
+    if (!load_builtins(interpreter_state)) {
+        interpreter_delete(interpreter_state);
+        return NULL;
+    }
+    return interpreter_state;
+}
+
+void clean_stack(StackItem *item) {
+    if (item == NULL) return;
+    if (item->type == STACK_TOKEN_STRING)
+        clean_token_string(item->token_string);
+    clean_stack(item->next);
+    free(item);
+}
+
+void interpreter_delete(InterpreterState *interpreter_state) {
+    clean_stack(interpreter_state->stack);
+    del_hash_table(interpreter_state->functions);
+    free(interpreter_state);
+}

SLS_C/src/lexer.c

@@ -32,6 +32,8 @@ const char *TOKEN_TYPES_NAMES[] = {
     "Type Tuple",
 };
 
+const size_t TOKEN_TYPE_COUNT = sizeof(TOKEN_TYPES_NAMES) / sizeof(*TOKEN_TYPES_NAMES);
+
 const char *ARRAY_TYPES_NAMES[] = {
     "Identifier",
     "i64",
@@ -50,6 +52,8 @@ const char *ARRAY_TYPES_NAMES[] = {
     "Inline Struct",
 };
 
+const size_t ARRAY_TYPE_COUNT = sizeof(ARRAY_TYPES_NAMES) / sizeof(*ARRAY_TYPES_NAMES);
+
 const char *INTEGER_TYPES_NAMES[] = {
     "i64",
     "i32",
@@ -61,6 +65,8 @@ const char *INTEGER_TYPES_NAMES[] = {
     "u8",
 };
 
+const size_t INTEGER_TYPE_COUNT = sizeof(INTEGER_TYPES_NAMES) / sizeof(*INTEGER_TYPES_NAMES);
+
 void init_lexer(LexerInfo *lexer_info, SlsStr filename, SlsStr source_code) {
     // Initializes a LexerInfo struct with file info and source code
     lexer_info->filename = filename;
@@ -325,40 +331,44 @@ static uint64_t create_hexadecimal_integer(LexerInfo *lexer_info, size_t start)
 static LexerResult create_integer_token(LexerInfo *lexer_info, IntegerBuiltInType type, uint64_t value, size_t start, size_t start_line) {
     switch (type) {
     case INTEGER_I64: break;
-    case INTEGER_U64: break;
     case INTEGER_I32:
-        if (value > (uint64_t)UINT32_MAX) {
+        if ((int64_t)value < INT32_MIN || (int64_t)value > INT32_MAX) {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for i32."), start, start_line);
         }
         break;
     case INTEGER_I16:
-        if (value > (uint64_t)UINT16_MAX) {
+        if ((int64_t)value < INT16_MIN || (int64_t)value > INT16_MAX) {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for i16."), start, start_line);
         }
         break;
     case INTEGER_I8:
-        if (value > (uint64_t)UINT8_MAX) {
+        if ((int64_t)value < INT8_MIN || (int64_t)value > INT8_MAX) {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for i8."), start, start_line);
         }
         break;
+    case INTEGER_U64:
+        if (seek(lexer_info, start) == '-') {
+            return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for u64."), start, start_line);
+        }
+        break;
     case INTEGER_U32:
         if (seek(lexer_info, start) == '-') {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for u32."), start, start_line);
-        } if (value > (uint64_t)UINT32_MAX) {
+        } else if (value > (uint64_t)UINT32_MAX) {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for u32."), start, start_line);
         }
         break;
     case INTEGER_U16:
         if (seek(lexer_info, start) == '-') {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for u16."), start, start_line);
-        } if (value > (uint64_t)UINT16_MAX) {
+        } else if (value > (uint64_t)UINT16_MAX) {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for u16."), start, start_line);
         }
         break;
     case INTEGER_U8:
         if (seek(lexer_info, start) == '-') {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for u8."), start, start_line);
-        } if (value > (uint64_t)UINT8_MAX) {
+        } else if (value > (uint64_t)UINT8_MAX) {
             return lexer_error(lexer_info, SLS_STR("Integer overflow: value exceeds range for u8."), start, start_line);
         }
         break;
@@ -511,7 +521,7 @@ static LexerResult parse_binary_integer(LexerInfo *lexer_info, char c, size_t st
     if (c == ':') return parse_numeric_type(lexer_info, c, start, start_line, NUMERIC_BINARY);
     if (isspace(c) || c == '/' || c == '\0') {
         uint64_t value = create_binary_integer(lexer_info, start);
-        return create_integer_token(lexer_info, INTEGER_I64, value, start, start_line);
+        return create_integer_token(lexer_info, SLS_INTEGER_TYPE_DEFAULT, value, start, start_line);
     }
     SlsStr error_msg = sls_format(SLS_STR("Invalid binary literal: unexpected '%c' in binary integer."), c);
     if (error_msg.str == NULL) return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Out Of Memory Error."), 1}};
@@ -523,7 +533,7 @@ static LexerResult parse_octal_integer(LexerInfo *lexer_info, char c, size_t sta
     if (c == ':') return parse_numeric_type(lexer_info, c, start, start_line, NUMERIC_OCTAL);
     if (isspace(c) || c == '/' || c == '\0') {
         uint64_t value = create_octal_integer(lexer_info, start);
-        return create_integer_token(lexer_info, INTEGER_I64, value, start, start_line);
+        return create_integer_token(lexer_info, SLS_INTEGER_TYPE_DEFAULT, value, start, start_line);
     }
     SlsStr error_msg = sls_format(SLS_STR("Invalid octal literal: unexpected '%c' in octal integer."), c);
     if (error_msg.str == NULL) return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Out Of Memory Error."), 1}};
@@ -540,7 +550,7 @@ static LexerResult parse_float(LexerInfo *lexer_info, char c, size_t start, size
     if (c == 'e' || c == 'E') return parse_exponential(lexer_info, c, start, start_line);
     if (c == ':') return parse_numeric_type(lexer_info, c, start, start_line, NUMERIC_FLOAT);
     if (isspace(c) || c == '/' || c == '\0')
-        return create_float_token(lexer_info, NUMERIC_F64, start, start_line);
+        return create_float_token(lexer_info, SLS_FLOAT_TYPE_DEFAULT, start, start_line);
     SlsStr error_msg = sls_format(SLS_STR("Invalid float literal: unexpected '%c' in float."), c);
     if (error_msg.str == NULL) return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Out Of Memory Error."), 1}};
     return lexer_error(lexer_info, error_msg, start, start_line);
@@ -555,7 +565,7 @@ static LexerResult parse_decimal_integer(LexerInfo *lexer_info, char c, size_t s
     if (c == ':') return parse_numeric_type(lexer_info, c, start, start_line, NUMERIC_DECIMAL);
     if (isspace(c) || c == '/' || c == '\0') {
         uint64_t value = create_decimal_integer(lexer_info, start);
-        return create_integer_token(lexer_info, INTEGER_I64, value, start, start_line);
+        return create_integer_token(lexer_info, SLS_INTEGER_TYPE_DEFAULT, value, start, start_line);
     }
     SlsStr error_msg = sls_format(SLS_STR("Invalid decimal literal: unexpected '%c' in decimal integer."), c);
     if (error_msg.str == NULL) return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Out Of Memory Error."), 1}};
@@ -567,7 +577,7 @@ static LexerResult parse_hexadecimal_integer(LexerInfo *lexer_info, char c, size
     if (c == ':') return parse_numeric_type(lexer_info, c, start, start_line, NUMERIC_HEXADECIMAL);
     if (isspace(c) || c == '/' || c == '\0') {
         uint64_t value = create_hexadecimal_integer(lexer_info, start);
-        return create_integer_token(lexer_info, INTEGER_I64, value, start, start_line);
+        return create_integer_token(lexer_info, SLS_INTEGER_TYPE_DEFAULT, value, start, start_line);
     }
     SlsStr error_msg = sls_format(SLS_STR("Invalid hexadecimal literal: unexpected '%c' in hexadecimal integer."), c);
     if (error_msg.str == NULL) return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Out Of Memory Error."), 1}};
@@ -642,9 +652,136 @@ static LexerResult parse_string_literal(LexerInfo *lexer_info, char c, size_t st
     return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Lexer: String Literals Not Implemented Error."), 1}};
 }
 
+static void skip_comments_and_whitespace(LexerInfo *lexer_info) {
+    while (isspace(peek(lexer_info)) || (peek(lexer_info) == '/' && far_peek(lexer_info, 1) == '/') || peek(lexer_info) == '#') {
+        // Skip Comments
+        if ((peek(lexer_info) == '/' && far_peek(lexer_info, 1) == '/') || peek(lexer_info) == '#')
+            while (!(peek(lexer_info) == '\n' || peek(lexer_info) == '\0'))
+                advance(lexer_info);
+        // Skip whitespace
+        while (isspace(peek(lexer_info))) advance(lexer_info);
+    }
+}
+
+static LexerResult lexer_next(LexerInfo *lexer_info);
+
+TokenString copy_token_string(TokenString token_string) {
+    TokenString new_string = (TokenString){
+        .length = token_string.length,
+        .tokens = (Token *)malloc(sizeof(Token) * token_string.length)
+    };
+
+    for (size_t i = 0; i < token_string.length; i++) {
+        if (token_string.tokens[i].type == TOKEN_STRING) {
+            new_string.tokens[i].type = TOKEN_STRING;
+            new_string.tokens[i].string_literal = sls_str_cpy(token_string.tokens[i].string_literal);
+        } else if (token_string.tokens[i].type == TOKEN_TOKEN_STRING) {
+            new_string.tokens[i].type = TOKEN_TOKEN_STRING;
+            new_string.tokens[i].token_string = copy_token_string(token_string.tokens[i].token_string);
+        } else {
+            new_string.tokens[i] = token_string.tokens[i];
+        }
+    }
+    return new_string;
+}
+
+static LexerResult convert_to_token_string(LexerInfo *lexer_info, LexerTokenResult *head, size_t start, size_t start_line) {
+    TokenString token_string = {
+        .length = 0,
+        .tokens = NULL
+    };
+    LexerTokenResult *current = head;
+
+    while (current != NULL) {
+        token_string.length += 1;
+        current = current->next;
+    }
+
+    current = head;
+    token_string.tokens = (Token *)malloc(sizeof(Token) * token_string.length);
+
+    for (size_t i = 0; i < token_string.length; i++) {
+        if (current->result.type == TOKEN_STRING) {
+            token_string.tokens[i].type = TOKEN_STRING;
+            token_string.tokens[i].string_literal = sls_str_cpy(current->result.string_literal);
+        } else if (current->result.type == TOKEN_TOKEN_STRING) {
+            token_string.tokens[i].type = TOKEN_TOKEN_STRING;
+            token_string.tokens[i].token_string = copy_token_string(current->result.token_string);
+            memcpy(token_string.tokens[i].token_string.tokens, current->result.token_string.tokens, current->result.token_string.length);
+        } else token_string.tokens[i] = current->result;
+        current = current->next;
+    }
+
+    clean_token_result(head);
+
+    return lexer_result(lexer_info, (Token){TOKEN_TOKEN_STRING, .token_string = token_string}, start, start_line);
+}
+
 static LexerResult parse_token_string(LexerInfo *lexer_info, char c, size_t start, size_t start_line) {
-    (void)lexer_info; (void)c; (void)start; (void)start_line;
-    return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Lexer: Token Strings Not Implemented Error."), 1}};
+    // Lexes a token string
+    LexerResult result; // For lexer_next returns
+    LexerTokenResult *head = 0;
+    LexerTokenResult *current = 0;
+
+    size_t watchdog = 0;
+
+    c = advance(lexer_info);
+    while (c != '\0') {
+        skip_comments_and_whitespace(lexer_info);
+        c = peek(lexer_info);
+
+        // Stop at the end of the token string
+        if (c == '}') {
+            advance(lexer_info);
+            return convert_to_token_string(lexer_info, head, start, start_line);
+        }
+
+        // Get next token
+        result = lexer_next(lexer_info);
+
+        // Handle Errors
+        if (result.type == SLS_ERROR) {
+            clean_token_result(head);
+            return result;
+        }
+
+        // Save result
+        if (head == 0) {
+            head = result.result;
+            current = head;
+        } else {
+            current->next = result.result;
+            current = current->next;
+        }
+
+        // Current should not be null_ptr
+        if (current == 0) {
+            clean_token_result(head);
+            return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Unknown Error."), 1}};
+        }
+
+        if (current->type == SLS_ERROR) {
+            LexerTokenResult *e = (LexerTokenResult *)malloc(sizeof(LexerTokenResult));
+            *e = (LexerTokenResult){
+                .type = SLS_ERROR,
+                .error = (SlsError){sls_str_cpy(current->error.message), 1},
+                .file_info = current->file_info,
+                .next = NULL
+            };
+            clean_token_result(head);
+            return (LexerResult){SLS_RESULT, .result = e};
+        }
+        if (current->result.type == TOKEN_EOF) break;
+
+        c = peek(lexer_info);
+
+        if (watchdog++ > 1000000) {
+            clean_token_result(head);
+            return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Watchdog Triggered in Token String."), 1}};
+        }
+    }
+    clean_token_result(head);
+    return lexer_error(lexer_info, SLS_STR("Unclosed token string: missing closing brace '}'."), start, start_line);
 }
 
 static LexerResult parse_array_literal(LexerInfo *lexer_info, char c, size_t start, size_t start_line) {
@@ -658,33 +795,43 @@ static LexerResult parse_type_tuples(LexerInfo *lexer_info, char c, size_t start
 }
 
 Boolean is_identifier_continue(LexerInfo *lexer_info, char c) {
+    // If the current character and its context are a valid identifier character
     if (!isprint(c)) return FALSE;
     if (c == '/' && far_peek(lexer_info, 1) == '/') return FALSE;
     if (c == '{' || c == '}') return FALSE;
     if (c == '[' || c == ']') return FALSE;
     if (c == '(' || c == ')') return FALSE;
-    if (c == '\'' || c == '"') return FALSE;
-    if (c == '.' || c == ':' || c == '#') return FALSE;
+    if (c == '\'' || c == '"' || c == '#') return FALSE;
     if (isspace(c) || c == '\0') return FALSE;
     return TRUE;
 }
 
-Boolean is_identifier_start(LexerInfo *lexer_info, char c) {
+Boolean is_identifier_start(LexerInfo *lexer_info) {
+    // If the current character and its context are a valid identifier start
+    char c = peek(lexer_info);
     if (c == ':' && far_peek(lexer_info, 1) == ':') c = far_peek(lexer_info, 2);
     if ((!isdigit(c)) && is_identifier_continue(lexer_info, c)) return TRUE;
     else return FALSE;
 }
 
 static LexerResult parse_identifiers_and_booleans(LexerInfo *lexer_info, char c, size_t start, size_t start_line) {
+    // Parses identifier, identifier literals, and boolean tokens
+
     Boolean literal = FALSE;
+    // Skip leading `::` for identifier literals
     if (c == ':' && far_peek(lexer_info, 1) == ':') {
         literal = TRUE;
         c = advance(lexer_info);
         c = advance(lexer_info);
     }
 
+    // Read the name of the identifier
     size_t length = 0;
     while (is_identifier_continue(lexer_info, c)) {
+        if (c == ':') // && !literal)
+            return lexer_error(lexer_info, SLS_STR("Invalid identifier: ':' is not allowed in identifiers."), start, start_line);
+        if (c == '.') // && !literal)
+            return lexer_error(lexer_info, SLS_STR("Invalid identifier: '.' is not allowed in identifiers."), start, start_line);
         c = advance(lexer_info);
         length++;
     }
@@ -693,6 +840,8 @@ static LexerResult parse_identifiers_and_booleans(LexerInfo *lexer_info, char c,
         name_value[i] = lexer_info->source_code.str[start + i + (2 * literal)];
     SlsStr name = sls_str_malloc(name_value, length);
     free(name_value);
+
+    // Return as identifier or boolean tokens
     if (sls_str_cmp(name, SLS_STR("false")) == 0)
         return lexer_result(lexer_info, (Token){TOKEN_BOOLEAN, .boolean_literal = FALSE}, start, start_line);
     else if (sls_str_cmp(name, SLS_STR("true")) == 0)
@@ -704,13 +853,7 @@ static LexerResult parse_identifiers_and_booleans(LexerInfo *lexer_info, char c,
 static LexerResult lexer_next(LexerInfo *lexer_info) {
     // Gets the next token from the source
 
-    while (isspace(peek(lexer_info)) || peek(lexer_info) == '/' || peek(lexer_info) == '#') {
-        // Skip Comments
-        if ((peek(lexer_info) == '/' && far_peek(lexer_info, 1) == '/') || peek(lexer_info) == '#')
-            while (peek(lexer_info) != '\n') advance(lexer_info);
-        // Skip whitespace
-        while (isspace(peek(lexer_info))) advance(lexer_info);
-    }
+    skip_comments_and_whitespace(lexer_info);
 
     // Initialize begining variables
     char c = peek(lexer_info);
@@ -731,29 +874,64 @@ static LexerResult lexer_next(LexerInfo *lexer_info) {
     if (c == '\"') return parse_string_literal(lexer_info, c, start, start_line);
     // Token Strings
     if (c == '{') return parse_token_string(lexer_info, c, start, start_line);
+    if (c == '}') {
+        advance(lexer_info);
+        return lexer_error(lexer_info, SLS_STR("Unexpected closing brace '}' without matching opening brace."), start, start_line);
+    }
     // Array Literals
     if (c == '[') return parse_array_literal(lexer_info, c, start, start_line);
+    if (c == ']') {
+        advance(lexer_info);
+        return lexer_error(lexer_info, SLS_STR("Unexpected closing bracket ']' without matching opening bracket."), start, start_line);
+    }
     // Type Tuples
     if (c == '(') return parse_type_tuples(lexer_info, c, start, start_line);
+    if (c == ')') {
+        advance(lexer_info);
+        return lexer_error(lexer_info, SLS_STR("Unexpected closing parentheses ')' without matching opening parentheses."), start, start_line);
+    }
     // Identifiers and Booleans
-    if (is_identifier_start(lexer_info, c))
+    if (is_identifier_start(lexer_info))
         return parse_identifiers_and_booleans(lexer_info, c, start, start_line);
-    // Lexing Error
-    return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Lexer: Unknown Character Error."), 1}};
+    if (c == ':') {
+        advance(lexer_info);
+        if (far_peek(lexer_info, 1) == ':')
+            return lexer_error(lexer_info, SLS_STR("Invalid identifier literal: empty identifier after '::'."), start, start_line);
+        else
+            return lexer_error(lexer_info, SLS_STR("Unexpected single colon ':'."), start, start_line);
+    }
+
+    // Random Characters
+    SlsStr error_msg = sls_format(SLS_STR("Unexpected character: unexpected '%c' during parsing."), c);
+    if (error_msg.str == NULL) return (LexerResult){SLS_ERROR, .error = (SlsError){SLS_STR("Out Of Memory Error."), 1}};
+    return lexer_error(lexer_info, error_msg, start, start_line);
+}
+
+void clean_token_string(TokenString token_string) {
+    if (token_string.tokens == NULL) return;
+    for (size_t i = 0; i < token_string.length; i++) {
+        if (token_string.tokens[i].type == TOKEN_STRING)
+            sls_str_free(&token_string.tokens[i].string_literal);
+        if (token_string.tokens[i].type == TOKEN_TOKEN_STRING)
+            clean_token_string(token_string.tokens[i].token_string);
+    }
+    free(token_string.tokens);
+    token_string.tokens = NULL;
 }
 
 void clean_token_result(LexerTokenResult *head) {
     // Deallocates a LexerTokenResult linked list
-    LexerTokenResult *next;
-    while (head) {
-        next = head->next;
+    if (head == NULL) return;
     if (head->type == SLS_ERROR) sls_str_free(&head->error.message);
     else {
-            if (head->result.type == TOKEN_STRING) sls_str_free(&head->error.message);
+        if (head->result.type == TOKEN_STRING)
+            sls_str_free(&head->result.string_literal);
+        if (head->result.type == TOKEN_TOKEN_STRING)
+            clean_token_string(head->result.token_string);
     }
+    clean_token_result(head->next);
+    head->next = NULL;
     if (head) free(head);
-        head = next;
-    }
 }
 
 LexerTokenResult *get_token(LexerTokenResult *head, size_t i) {

SLS_C/src/main.c

@@ -4,8 +4,37 @@
 // October 2025
 
 #include <stdio.h>
+#include <stddef.h>
+#include <string.h>
 
-int main(void) {
-    printf("Hello, world!\n");
-    return 0;
+#include "sls/meta.h"
+#include "sls/bool.h"
+#include "sls/string.h"
+#include "sls/repl.h"
+#include "sls/file.h"
+
+int main(int argc, char *argv[]) {
+    Boolean version = FALSE;
+    char *filename = NULL;
+
+    if (argc == 2) {
+        if (strcmp(argv[1], "--version") == 0) version = TRUE;
+        else if (strcmp(argv[1], "-v") == 0) version = TRUE;
+        else filename = argv[1];
+    } else if (argc > 2) {
+        printf("To many arguments!");
+        return 1;
+    }
+
+    if (version) {
+        print_version();
+        return 0;
+    } else if (filename != NULL) {
+        SlsStr sls_filename = sls_str_malloc(filename, strlen(filename));
+        int rv = file(sls_filename);
+        sls_str_free(&sls_filename);
+        return rv;
+    } else {
+        return repl();
+    }
 }

SLS_C/src/meta.c

@@ -0,0 +1,13 @@
+// Kyler Olsen
+// YREA SLS
+// MEta File
+// November 2025
+
+#include <stdio.h>
+
+#include "sls/meta.h"
+
+void print_version() {
+    printf("YREA SLS (" SLS_NAME ") " SLS_VER " (" GIT_COMMIT_HASH ")\n");
+    printf("Compiled with " COMPILER_NAME " %d at " __DATE__ " " __TIME__ "\n", COMPILER_VER);
+}

SLS_C/src/pico_main.c

@@ -0,0 +1,205 @@
+// Kyler Olsen
+// YREA SLS
+// Pico Main File
+// December 2025
+
+#include <stdio.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "pico/stdlib.h"
+#include "pico/stdio_usb.h"
+#include "hardware/uart.h"
+#include "hardware/gpio.h"
+
+#include "sls/meta.h"
+#include "sls/bool.h"
+#include "sls/string.h"
+#include "sls/errors.h"
+#include "sls/lexer.h"
+#include "sls/interpreter.h"
+
+// Pico onboard LED
+#define LED_PIN 25
+
+static const SlsStr PICO_REPL_NAME = SLS_STR_CONST("<PICO-REPL>");
+
+void print_top_of_stack(InterpreterState *interpreter_state) {
+    if (interpreter_state->stack == NULL) {
+        printf("#0: <STACK IS EMPTY>\n");
+        return;
+    }
+    switch (interpreter_state->stack->type) {
+    case STACK_IDENTIFIER:
+        printf("#0: ::%s\n", interpreter_state->stack->identifier.name.str);
+        break;
+    case STACK_I64:
+        printf("#0: %ld:i64\n", interpreter_state->stack->i64);
+        break;
+    case STACK_I32:
+        printf("#0: %d\n", interpreter_state->stack->i32);
+        break;
+    case STACK_I16:
+        printf("#0: %d:i16\n", interpreter_state->stack->i16);
+        break;
+    case STACK_I8:
+        printf("#0: %d:i8\n", interpreter_state->stack->i8);
+        break;
+    case STACK_U64:
+        printf("#0: %lu:u64\n", interpreter_state->stack->u64);
+        break;
+    case STACK_U32:
+        printf("#0: %u:u32\n", interpreter_state->stack->u32);
+        break;
+    case STACK_U16:
+        printf("#0: %u:u16\n", interpreter_state->stack->u16);
+        break;
+    case STACK_U8:
+        printf("#0: %u:u8\n", interpreter_state->stack->u8);
+        break;
+    case STACK_FLOAT:
+        printf("#0: %f:f32\n", interpreter_state->stack->f32);
+        break;
+    case STACK_DOUBLE:
+        printf("#0: %f\n", interpreter_state->stack->f64);
+        break;
+    case STACK_CHARACTER:
+        printf("#0: %c\n", interpreter_state->stack->character);
+        break;
+    case STACK_BOOLEAN:
+        if (interpreter_state->stack->boolean) printf("#0: TRUE\n");
+        else printf("#0: FALSE\n");
+        break;
+    case STACK_TOKEN_STRING:
+        printf("#0: <TOKEN STRING>\n");
+        break;
+    case STACK_CALLABLE:
+        printf("#0: <CALLABLE>\n");
+        break;
+    }
+}
+
+void led_blink(int count) {
+    for (int i = 0; i < count; i++) {
+        gpio_put(LED_PIN, 1);
+        sleep_ms(100);
+        gpio_put(LED_PIN, 0);
+        sleep_ms(100);
+    }
+}
+
+int pico_repl() {
+    // Initialize LED
+    gpio_init(LED_PIN);
+    gpio_set_dir(LED_PIN, GPIO_OUT);
+
+    // Blink to show we're ready
+    led_blink(3);
+
+    // Wait for a key press to start the repl
+    while (true) {
+        int c = getchar_timeout_us(100000);
+        if (c == PICO_ERROR_TIMEOUT) {
+            continue;
+        } else if (c == '\r' || c == '\n' || c == 8 || (c >= 32 && c < 128)) {
+            printf("\n");
+            break;
+        }
+    }
+
+    led_blink(1);
+
+    print_version();
+    printf("===== YREA SLS PICO REPL =====\n");
+    printf("Type `#exit` to exit.\n");
+    fflush(stdout);
+
+    LexerInfo lexer_info;
+    InterpreterState *interpreter_state = interpreter_create();
+    if (interpreter_state == NULL) {
+        printf("ERROR: Failed to create interpreter!\n");
+        return 1;
+    }
+
+    char buf[256];
+    int buf_pos = 0;
+
+    while (true) {
+        // Read character by character for better embedded behavior
+        int c = getchar_timeout_us(100000); // 100ms timeout
+
+        if (c == PICO_ERROR_TIMEOUT) {
+            continue;
+        }
+
+        if (c == '\r' || c == '\n') {
+            if (buf_pos == 0) continue; // Empty line
+
+            buf[buf_pos] = '\0';
+            printf("\n"); // Echo newline
+
+            if (strncmp(buf, "#exit", 5) == 0) {
+                printf("Exiting REPL...\n");
+                interpreter_delete(interpreter_state);
+                led_blink(2);
+                return 0;
+            }
+
+            SlsStr code = sls_str_malloc(buf, buf_pos);
+            init_lexer(&lexer_info, PICO_REPL_NAME, code);
+            LexerResult result = lexical_analysis(&lexer_info);
+
+            if (result.type == SLS_ERROR) {
+                printf("%s\n", result.error.message.str);
+                sls_str_free(&result.error.message);
+            } else {
+                LexerTokenResult *head = result.result;
+                while (head) {
+                    if (head->type == SLS_ERROR) {
+                        printf("%s\n", head->error.message.str);
+                        break;
+                    } else if (!execute(interpreter_state, head)) {
+                        printf("A runtime error occurred!\n");
+                        break;
+                    }
+                    head = head->next;
+                }
+                clean_token_result(result.result);
+                print_top_of_stack(interpreter_state);
+            }
+            sls_str_free(&code);
+
+            buf_pos = 0;
+
+        } else if (c == 127 || c == 8) {
+            // Backspace or DEL
+            if (buf_pos > 0) {
+                buf_pos--;
+                printf("\b \b"); // Erase character from terminal
+                fflush(stdout);
+            }
+        } else if (c >= 32 && c < 127 && buf_pos < 255) {
+            // Printable character
+            buf[buf_pos++] = (char)c;
+            putchar(c); // Echo character
+            fflush(stdout);
+        }
+    }
+
+    interpreter_delete(interpreter_state);
+    return 1;
+}
+
+int main() {
+    // Initialize USB/UART stdio
+    stdio_init_all();
+    // Wait a bit for USB to enumerate
+    sleep_ms(5000);
+
+    printf("\n\n=============================\n");
+    printf("YREA SLS on Raspberry Pi Pico\n");
+    printf("=============================\n\n");
+    printf("Press any key to begin...\n");
+
+    return pico_repl();
+}

SLS_C/src/repl.c

@@ -0,0 +1,118 @@
+// Kyler Olsen
+// YREA SLS
+// REPL
+// November 2025
+
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "sls/repl.h"
+#include "sls/meta.h"
+#include "sls/errors.h"
+#include "sls/lexer.h"
+#include "sls/string.h"
+#include "sls/interpreter.h"
+
+static const SlsStr REPL_FILE_NAME = SLS_STR_CONST("<STDIN>");
+
+void print_top_of_stack(InterpreterState *interpreter_state) {
+    if (interpreter_state->stack == NULL) {
+        printf("#0: <STACK IS EMPTY>\n");
+        return;
+    }
+    switch (interpreter_state->stack->type) {
+    case STACK_IDENTIFIER:
+        printf("#0: ::%s\n", interpreter_state->stack->identifier.name.str);
+        break;
+    case STACK_I64:
+        printf("#0: %ld\n", interpreter_state->stack->i64);
+        break;
+    case STACK_I32:
+        printf("#0: %d:i32\n", interpreter_state->stack->i32);
+        break;
+    case STACK_I16:
+        printf("#0: %d:i16\n", interpreter_state->stack->i16);
+        break;
+    case STACK_I8:
+        printf("#0: %d:8\n", interpreter_state->stack->i8);
+        break;
+    case STACK_U64:
+        printf("#0: %lu:u64\n", interpreter_state->stack->u64);
+        break;
+    case STACK_U32:
+        printf("#0: %u:32\n", interpreter_state->stack->u32);
+        break;
+    case STACK_U16:
+        printf("#0: %u:16\n", interpreter_state->stack->u16);
+        break;
+    case STACK_U8:
+        printf("#0: %u:8\n", interpreter_state->stack->u8);
+        break;
+    case STACK_FLOAT:
+        printf("#0: %f:f32\n", interpreter_state->stack->f32);
+        break;
+    case STACK_DOUBLE:
+        printf("#0: %f\n", interpreter_state->stack->f64);
+        break;
+    case STACK_CHARACTER:
+        printf("#0: %c\n", interpreter_state->stack->character);
+        break;
+    case STACK_BOOLEAN:
+        if (interpreter_state->stack->boolean) printf("#0: TRUE\n");
+        else printf("#0: FALSE\n");
+        break;
+    case STACK_TOKEN_STRING:
+        printf("#0: <TOKEN STRING>\n");
+        break;
+    case STACK_CALLABLE:
+        printf("#0: <CALLABLE>\n");
+        break;
+    }
+}
+
+int repl() {
+    print_version();
+    printf("===== YREA SLS REPL =====\n");
+    printf("Type `#exit` to exit.\n");
+    fflush(stdout);
+
+    LexerInfo lexer_info;
+    InterpreterState *interpreter_state = interpreter_create();
+    if (interpreter_state == NULL) return 1;
+    char buf[256];
+    while (fgets(buf, sizeof(buf), stdin)) {
+        size_t len = strlen(buf);
+        if (len && buf[len - 1] == '\n') buf[len - 1] = '\0';
+        if (strncmp(buf, "#exit", 5) == 0) {
+            interpreter_delete(interpreter_state);
+            return 0;
+        }
+
+        SlsStr code = sls_str_malloc(buf, sizeof(buf));
+        init_lexer(&lexer_info, REPL_FILE_NAME, code);
+        LexerResult result = lexical_analysis(&lexer_info);
+        if (result.type == SLS_ERROR) {
+            printf("%s\n", result.error.message.str);
+            sls_str_free(&result.error.message);
+        } else {
+            LexerTokenResult *head = result.result;
+            while (head) {
+                if (head->type == SLS_ERROR) {
+                    printf("%s\n", head->error.message.str);
+                    break;
+                } else if (!execute(interpreter_state, head)) {
+                    printf("A runtime error occurred!\n");
+                    break;
+                }
+                head = head->next;
+            }
+            clean_token_result(result.result);
+            print_top_of_stack(interpreter_state);
+        }
+        sls_str_free(&code);
+    }
+
+    interpreter_delete(interpreter_state);
+    return 1;
+}

SLS_C/src/string.c

@@ -204,18 +204,30 @@ SlsStr sls_format(const SlsStr s, ...) {
         case 't':
             items[i].type = FORMAT_SLS_TOKEN_TYPE;
             items[i].token_type = va_arg(args, TokenType);
+            if (items[i].token_type >= TOKEN_TYPE_COUNT) {
+                free(items);
+                return SLS_STR_NULL;
+            }
             length += items[i].self_length = sls_str_nlen(TOKEN_TYPES_NAMES[items[i].token_type], TYPE_NAMES_SAFE_LENGTH);
             length -= 2;
             break;
         case 'a':
             items[i].type = FORMAT_SLS_ARRAY_TYPE;
             items[i].array_type = va_arg(args, ArrayType);
+            if (items[i].array_type >= ARRAY_TYPE_COUNT) {
+                free(items);
+                return SLS_STR_NULL;
+            }
             length += items[i].self_length = sls_str_nlen(ARRAY_TYPES_NAMES[items[i].array_type], TYPE_NAMES_SAFE_LENGTH);
             length -= 2;
             break;
         case 'i':
             items[i].type = FORMAT_SLS_BUILTIN_INTEGER;
             items[i].builtin_integer = va_arg(args, IntegerBuiltInType);
+            if (items[i].builtin_integer >= INTEGER_TYPE_COUNT) {
+                free(items);
+                return SLS_STR_NULL;
+            }
             length += items[i].self_length = sls_str_nlen(INTEGER_TYPES_NAMES[items[i].builtin_integer], TYPE_NAMES_SAFE_LENGTH);
             length -= 2;
             break;
@@ -309,7 +321,7 @@ SlsStr sls_format(const SlsStr s, ...) {
         target_i += items[item_i].self_length;
         item_i++;
     }
-    if (s.len > source_i)
+    if (s.len > (size_t)source_i)
         memcpy(str + target_i, s.str + source_i, s.len - source_i);
     str[str_new.len] = '\0';
 

SLS_C/tests/extra_tests.c

@@ -11,9 +11,30 @@
 #include "sls/string.h"
 #include "sls/lexer.h"
 #include "sls/errors.h"
+#include "tests/lexer_test_helpers.h"
 #include "tests/tests.h"
 
-static const size_t NUM_EXTRA_TESTS = 0;
+static const size_t NUM_EXTRA_TESTS = 2;
+
+static TestResult test_Identifier_Addition() {
+    LexerTest test = start_up_test(SLS_STR("Identifier Addition"), SLS_STR("+"));
+    LexerResult result = lexical_analysis(&test.lexer_info);
+    if (result.type == SLS_ERROR) return error_fail_test(&test, result, result.error);
+    size_t i = 0;
+    if (test_identifier_value(&test, result, i++, &(TestIdentifierValue){FALSE, SLS_STR("+")})) return test.result;
+    if (test_eof_value(&test, result, i++, 0)) return test.result;
+    return pass_test(&test, result);
+}
+
+static TestResult test_Identifier_Division() {
+    LexerTest test = start_up_test(SLS_STR("Identifier Division"), SLS_STR("/"));
+    LexerResult result = lexical_analysis(&test.lexer_info);
+    if (result.type == SLS_ERROR) return error_fail_test(&test, result, result.error);
+    size_t i = 0;
+    if (test_identifier_value(&test, result, i++, &(TestIdentifierValue){FALSE, SLS_STR("/")})) return test.result;
+    if (test_eof_value(&test, result, i++, 0)) return test.result;
+    return pass_test(&test, result);
+}
 
 // Run all extra tests
 TestsReport run_extra_tests()
@@ -24,6 +45,8 @@ TestsReport run_extra_tests()
         .tests = malloc(sizeof(TestResult) * NUM_EXTRA_TESTS)};
 
     size_t i = 0;
-    // report.tests[i++] = test_malloc_and_copy();
+    (void)i;
+    report.tests[i++] = test_Identifier_Addition();
+    report.tests[i++] = test_Identifier_Division();
     return report;
 }

SLS_C/tests/hash_table_tests.c

@@ -0,0 +1,383 @@
+// Kyler Olsen
+// YREA SLS
+// Hash Table Tests
+// November 2025
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "sls/string.h"
+#include "sls/hash_table.h"
+#include "tests/tests.h"
+
+static const size_t NUM_HASH_TABLE_TESTS = 12;
+
+static TestResult pass_hash_table_test(SlsStr test_name) {
+    TestResult result = {.name = test_name, .status = TEST_NOT_IMPLEMENTED};
+    result.status = TEST_PASS;
+    return result;
+}
+
+static TestResult fail_hash_table_test(SlsStr test_name, SlsStr message) {
+    TestResult result = { .name = test_name, .status = TEST_NOT_IMPLEMENTED };
+    result.status = TEST_ERROR;
+    result.message = sls_str_cpy(message);
+
+    if (result.message.str == NULL) {
+        result.error = (SlsError){ SLS_STR("Out Of Memory Error."), 1 };
+        result.status = TEST_ERROR;
+    }
+    return result;
+}
+
+// Test init_hash_table and del_hash_table
+static TestResult test_init_and_delete() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_init_and_delete"), SLS_STR("Initialization failed"));
+    
+    if (ht->buckets_count < 10) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_init_and_delete"), SLS_STR("Bucket count less than minimum"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_init_and_delete"));
+}
+
+// Test basic put and get operations
+static TestResult test_put_and_get() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_put_and_get"), SLS_STR("Initialization failed"));
+
+    int value1 = 42;
+    int value2 = 84;
+    SlsStr key1 = SLS_STR("key1");
+    SlsStr key2 = SLS_STR("key2");
+
+    if (!hash_table_put(ht, key1, &value1)) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_put_and_get"), SLS_STR("Put operation failed"));
+    }
+
+    if (!hash_table_put(ht, key2, &value2)) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_put_and_get"), SLS_STR("Second put operation failed"));
+    }
+
+    int *retrieved1 = (int*)hash_table_get(ht, key1, NULL);
+    int *retrieved2 = (int*)hash_table_get(ht, key2, NULL);
+
+    if (!retrieved1 || *retrieved1 != 42) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_put_and_get"), SLS_STR("Get operation failed for key1"));
+    }
+
+    if (!retrieved2 || *retrieved2 != 84) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_put_and_get"), SLS_STR("Get operation failed for key2"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_put_and_get"));
+}
+
+// Test get with non-existent key returns default
+static TestResult test_get_nonexistent_key() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_get_nonexistent_key"), SLS_STR("Initialization failed"));
+
+    int default_value = -1;
+    SlsStr key = SLS_STR("nonexistent");
+
+    int *result = (int*)hash_table_get(ht, key, &default_value);
+    if (result != &default_value) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_get_nonexistent_key"), SLS_STR("Did not return default value"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_get_nonexistent_key"));
+}
+
+// Test updating existing key
+static TestResult test_update_existing_key() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_update_existing_key"), SLS_STR("Initialization failed"));
+
+    int value1 = 100;
+    int value2 = 200;
+    SlsStr key = SLS_STR("update_key");
+
+    hash_table_put(ht, key, &value1);
+    hash_table_put(ht, key, &value2);
+
+    int *result = (int*)hash_table_get(ht, key, NULL);
+    if (!result || *result != 200) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_update_existing_key"), SLS_STR("Update failed"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_update_existing_key"));
+}
+
+// Test delete operation
+static TestResult test_delete_key() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_delete_key"), SLS_STR("Initialization failed"));
+
+    int value = 42;
+    SlsStr key = SLS_STR("delete_key");
+
+    hash_table_put(ht, key, &value);
+
+    if (!hash_table_del(ht, key)) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_delete_key"), SLS_STR("Delete returned FALSE"));
+    }
+
+    int default_val = -1;
+    int *result = (int*)hash_table_get(ht, key, &default_val);
+    if (result != &default_val) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_delete_key"), SLS_STR("Key still exists after delete"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_delete_key"));
+}
+
+// Test delete non-existent key returns FALSE
+static TestResult test_delete_nonexistent_key() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_delete_nonexistent_key"), SLS_STR("Initialization failed"));
+
+    SlsStr key = SLS_STR("nonexistent");
+
+    if (hash_table_del(ht, key)) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_delete_nonexistent_key"), SLS_STR("Delete returned TRUE for nonexistent key"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_delete_nonexistent_key"));
+}
+
+// Test collision handling (multiple keys in same bucket)
+static TestResult test_collision_handling() {
+    HashTable *ht = init_hash_table(1); // Force collisions with single bucket
+    if (!ht) return fail_hash_table_test(SLS_STR("test_collision_handling"), SLS_STR("Initialization failed"));
+
+    int val1 = 1, val2 = 2, val3 = 3;
+    SlsStr key1 = SLS_STR("key1");
+    SlsStr key2 = SLS_STR("key2");
+    SlsStr key3 = SLS_STR("key3");
+
+    hash_table_put(ht, key1, &val1);
+    hash_table_put(ht, key2, &val2);
+    hash_table_put(ht, key3, &val3);
+
+    int *r1 = (int*)hash_table_get(ht, key1, NULL);
+    int *r2 = (int*)hash_table_get(ht, key2, NULL);
+    int *r3 = (int*)hash_table_get(ht, key3, NULL);
+
+    if (!r1 || *r1 != 1 || !r2 || *r2 != 2 || !r3 || *r3 != 3) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_collision_handling"), SLS_STR("Collision handling failed"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_collision_handling"));
+}
+
+// Test empty string key
+static TestResult test_empty_key() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_empty_key"), SLS_STR("Initialization failed"));
+
+    int value = 99;
+    SlsStr key = SLS_STR("");
+
+    if (!hash_table_put(ht, key, &value)) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_empty_key"), SLS_STR("Put with empty key failed"));
+    }
+
+    int *result = (int*)hash_table_get(ht, key, NULL);
+    if (!result || *result != 99) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_empty_key"), SLS_STR("Get with empty key failed"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_empty_key"));
+}
+
+// Test long key
+static TestResult test_long_key() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_long_key"), SLS_STR("Initialization failed"));
+
+    char long_key_str[256];
+    for (size_t i = 0; i < 255; i++) long_key_str[i] = 'A';
+    long_key_str[255] = '\0';
+
+    SlsStr key = sls_str_malloc(long_key_str, 255);
+    int value = 777;
+
+    if (!hash_table_put(ht, key, &value)) {
+        sls_str_free(&key);
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_long_key"), SLS_STR("Put with long key failed"));
+    }
+
+    int *result = (int*)hash_table_get(ht, key, NULL);
+    if (!result || *result != 777) {
+        sls_str_free(&key);
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_long_key"), SLS_STR("Get with long key failed"));
+    }
+
+    sls_str_free(&key);
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_long_key"));
+}
+
+// Test multiple operations sequence
+static TestResult test_multiple_operations() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_multiple_operations"), SLS_STR("Initialization failed"));
+
+    int vals[5] = {10, 20, 30, 40, 50};
+    SlsStr keys[5] = {SLS_STR("k1"), SLS_STR("k2"), SLS_STR("k3"), SLS_STR("k4"), SLS_STR("k5")};
+
+    // Insert all
+    for (int i = 0; i < 5; i++) {
+        if (!hash_table_put(ht, keys[i], &vals[i])) {
+            del_hash_table(ht);
+            return fail_hash_table_test(SLS_STR("test_multiple_operations"), SLS_STR("Insert failed"));
+        }
+    }
+
+    // Delete some
+    hash_table_del(ht, keys[1]);
+    hash_table_del(ht, keys[3]);
+
+    // Verify remaining
+    int *r0 = (int*)hash_table_get(ht, keys[0], NULL);
+    int *r2 = (int*)hash_table_get(ht, keys[2], NULL);
+    int *r4 = (int*)hash_table_get(ht, keys[4], NULL);
+
+    if (!r0 || *r0 != 10 || !r2 || *r2 != 30 || !r4 || *r4 != 50) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_multiple_operations"), SLS_STR("Get after delete failed"));
+    }
+
+    // Verify deleted
+    int def = -1;
+    int *r1 = (int*)hash_table_get(ht, keys[1], &def);
+    int *r3 = (int*)hash_table_get(ht, keys[3], &def);
+
+    if (r1 != &def || r3 != &def) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_multiple_operations"), SLS_STR("Deleted keys still present"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_multiple_operations"));
+}
+
+// Test storing NULL pointers
+static TestResult test_null_value() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_null_value"), SLS_STR("Initialization failed"));
+
+    SlsStr key = SLS_STR("null_key");
+    
+    if (!hash_table_put(ht, key, NULL)) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_null_value"), SLS_STR("Put with NULL value failed"));
+    }
+
+    int default_val = -1;
+    void *result = hash_table_get(ht, key, &default_val);
+    
+    // Should retrieve NULL, not default
+    if (result == &default_val) {
+        del_hash_table(ht);
+        return fail_hash_table_test(SLS_STR("test_null_value"), SLS_STR("NULL value not stored correctly"));
+    }
+
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_null_value"));
+}
+
+// Test large number of entries
+static TestResult test_large_capacity() {
+    HashTable *ht = init_hash_table(10);
+    if (!ht) return fail_hash_table_test(SLS_STR("test_large_capacity"), SLS_STR("Initialization failed"));
+
+    const size_t COUNT = 100;
+    int *values = malloc(sizeof(int) * COUNT);
+    SlsStr *keys = malloc(sizeof(SlsStr) * COUNT);
+
+    for (size_t i = 0; i < COUNT; i++) {
+        values[i] = (int)i;
+        char key_buf[32];
+        snprintf(key_buf, 32, "key_%zu", i);
+        keys[i] = sls_str_malloc(key_buf, strlen(key_buf));
+        
+        if (!hash_table_put(ht, keys[i], &values[i])) {
+            for (size_t j = 0; j <= i; j++) sls_str_free(&keys[j]);
+            free(keys);
+            free(values);
+            del_hash_table(ht);
+            return fail_hash_table_test(SLS_STR("test_large_capacity"), SLS_STR("Put failed in bulk insert"));
+        }
+    }
+
+    // Verify all entries
+    for (size_t i = 0; i < COUNT; i++) {
+        int *result = (int*)hash_table_get(ht, keys[i], NULL);
+        if (!result || *result != (int)i) {
+            for (size_t j = 0; j < COUNT; j++) sls_str_free(&keys[j]);
+            free(keys);
+            free(values);
+            del_hash_table(ht);
+            return fail_hash_table_test(SLS_STR("test_large_capacity"), SLS_STR("Get failed in bulk verify"));
+        }
+    }
+
+    for (size_t i = 0; i < COUNT; i++) sls_str_free(&keys[i]);
+    free(keys);
+    free(values);
+    del_hash_table(ht);
+    return pass_hash_table_test(SLS_STR("test_large_capacity"));
+}
+
+// Run all hash table tests
+TestsReport run_hash_table_tests() {
+    TestsReport report = {
+        .section = SLS_STR("hash_table_tests"),
+        .count = NUM_HASH_TABLE_TESTS,
+        .tests = malloc(sizeof(TestResult) * NUM_HASH_TABLE_TESTS)
+    };
+
+    size_t i = 0;
+    report.tests[i++] = test_init_and_delete();
+    report.tests[i++] = test_put_and_get();
+    report.tests[i++] = test_get_nonexistent_key();
+    report.tests[i++] = test_update_existing_key();
+    report.tests[i++] = test_delete_key();
+    report.tests[i++] = test_delete_nonexistent_key();
+    report.tests[i++] = test_collision_handling();
+    report.tests[i++] = test_empty_key();
+    report.tests[i++] = test_long_key();
+    report.tests[i++] = test_multiple_operations();
+    report.tests[i++] = test_null_value();
+    report.tests[i++] = test_large_capacity();
+    
+    return report;
+}

SLS_C/tests/lexer_test_helpers.c

@@ -116,20 +116,25 @@ static SlsStr expected_end_of_token_stream(size_t i) {
 }
 
 static SlsStr token_should_be(size_t i, TokenType should, TokenType found) {
+    if (found >= TOKEN_TYPE_COUNT)
+        return sls_format(SLS_STR("Token #%z should be a %t, but found invalid enum %u"), i, should, (uint64_t)found);
+    else
         return sls_format(SLS_STR("Token #%z should be a %t, but found a %t"), i, should, found);
 }
 
 static SlsStr integer_type_should_be(size_t i, IntegerBuiltInType should, IntegerBuiltInType found) {
+    if (found >= INTEGER_TYPE_COUNT)
+        return sls_format(SLS_STR("Token #%z integer type should be a %i, but found invalid enum %u"), i, should, (uint64_t)found);
+    else
         return sls_format(SLS_STR("Token #%z integer type should be a %i, but found a %i"), i, should, found);
 }
 
 static SlsStr integer_value_should_be(size_t i, uint64_t should, uint64_t found) {
-    return sls_format(SLS_STR("Token #%z integer value should be %i, but found %i"), i, should, found);
+    return sls_format(SLS_STR("Token #%z integer value should be %u, but found %u"), i, should, found);
 }
 
 static SlsStr character_value_should_be(size_t i, uint8_t should, uint8_t found) {
     return sls_format(SLS_STR("Token #%z integer value should be %i, but found %i"), i, should, found);
-    // return sls_format(SLS_STR("Token #%z character value should be '', but found ''"), i, should[0], found[0]);
 }
 
 static SlsStr float_value_should_be(size_t i, double should, double found) {
@@ -158,6 +163,9 @@ static SlsStr boolean_should_be(size_t i, Boolean value) {
 }
 
 static SlsStr array_type_should_be(size_t i, ArrayType should, ArrayType found) {
+    if (found >= ARRAY_TYPE_COUNT)
+        return sls_format(SLS_STR("Token #%z should be a %a, but found invalid enum %u"), i, should, (uint64_t)found);
+    else
         return sls_format(SLS_STR("Token #%z should be a %a, but found a %a"), i, should, found);
 }
 
@@ -486,9 +494,38 @@ Boolean test_array_struct_inline_value(LexerTest *test, LexerResult result, size
 static LexerResult token_string_to_lexer_result(TokenString token_string, FileInfo file_info) {
     LexerTokenResult *new, *head;
     head = 0;
-    for (size_t i = 0; i> token_string.length; i++) {
+    for (size_t i = token_string.length; i > 0; i--) {
         new = (LexerTokenResult *)malloc(sizeof(LexerTokenResult));
-        *new = (LexerTokenResult) { .type = SLS_RESULT, .result = token_string.tokens[i], .file_info = file_info, .next = head };
+        if (new == 0) return (LexerResult) { .type = SLS_ERROR, .error = (SlsError){SLS_STR("Out Of Memory Error."), 1} };
+        if (token_string.tokens[i-1].type == TOKEN_STRING) {
+            *new = (LexerTokenResult) {
+                .type = SLS_RESULT,
+                .result = (Token){
+                    .type = TOKEN_STRING,
+                    .string_literal = sls_str_cpy(token_string.tokens[i-1].string_literal)
+                },
+                .file_info = file_info,
+                .next = head
+            };
+        } else if (token_string.tokens[i-1].type == TOKEN_TOKEN_STRING) {
+            *new = (LexerTokenResult) {
+                .type = SLS_RESULT,
+                .result = (Token){
+                    .type = TOKEN_TOKEN_STRING,
+                    .token_string = copy_token_string(token_string.tokens[i-1].token_string)
+                },
+                .file_info = file_info,
+                .next = head
+            };
+            memcpy(new->result.token_string.tokens, token_string.tokens[i-1].token_string.tokens, token_string.tokens[i-1].token_string.length);
+        } else {
+            *new = (LexerTokenResult) {
+                .type = SLS_RESULT,
+                .result = token_string.tokens[i-1],
+                .file_info = file_info,
+                .next = head
+            };
+        }
         head = new;
     }
     return (LexerResult) { .type = SLS_RESULT, .result = head };
@@ -506,7 +543,8 @@ Boolean test_token_string_value(LexerTest *test, LexerResult result, size_t i, T
     for (size_t j = 0; j < values->tokens; j++) {
         LexerResult token_string_result = token_string_to_lexer_result(head->result.token_string, head->file_info);
         if (values->values[j].token_handler(test, token_string_result, j, values->values[j].value)) {
-            clean_token_result(token_string_result.result);
+            // We do not clean up here because if token_handler fails the test, it cleans up for us.
+            // clean_token_result(token_string_result.result);
             return TRUE;
         }
         clean_token_result(token_string_result.result);
@@ -551,13 +589,13 @@ Boolean test_type_tuple_value(LexerTest *test, LexerResult result, size_t i, Tes
     return FALSE;
 }
 
-Boolean test_for_error(LexerTest *test, LexerResult result, size_t i, SlsStr error) {
+Boolean test_for_error(LexerTest *test, LexerResult result, size_t i, SlsStr *error) {
     LexerTokenResult *head = get_token(result.result, i);
     if (head->type != SLS_ERROR) {
-        logic_fail_test(test, result, token_should_be_error(i + 1, error, head->result.type));
+        logic_fail_test(test, result, token_should_be_error(i + 1, *error, head->result.type));
         return TRUE;
-    } if (sls_str_cmp(head->error.message, error) != 0) {
-        logic_fail_test(test, result, error_should_be(i + 1, error, head->error));
+    } if (sls_str_cmp(head->error.message, *error) != 0) {
+        logic_fail_test(test, result, error_should_be(i + 1, *error, head->error));
         return TRUE;
     }
     return FALSE;

SLS_C/tests/tests.c

@@ -10,9 +10,9 @@
 #include "sls/errors.h"
 #include "tests/tests.h"
 
-static const Boolean PRINT_SUCCESSFUL_TESTS = TRUE;
+static const Boolean PRINT_SUCCESSFUL_TESTS = FALSE;
 
-const SlsStr TEST_FILE_NAME = SLS_STR("TEST_FILE.SLS");
+const SlsStr TEST_FILE_NAME = SLS_STR_CONST("TEST_FILE.SLS");
 
 typedef struct {
     uint16_t errored;
@@ -85,6 +85,8 @@ int main(void) {
     test_report(run_string_tests(), &counts);
     printf("    ========== Lexer Tests ==========\n");
     test_report(run_lexer_tests(), &counts);
+    printf("    ========== Hash Table Tests ==========\n");
+    test_report(run_hash_table_tests(), &counts);
     printf("    ========== Extra Tests ==========\n");
     test_report(run_extra_tests(), &counts);
 

SLS_Python/.gitignore

@@ -0,0 +1,4 @@
+__pycache__/
+.venv/
+sls_python.egg-info/
+dist/

SLS_Python/README.md

@@ -0,0 +1,19 @@
+# SLS Python
+
+This is the Python implementation for the YREA SLS interpreter.
+
+## Building
+
+```bash
+cd SLS_Python
+python -m venv .venv
+source .venv/bin/activate
+
+pip install build wheel "setuptools>=61.0"
+
+# Install the backend (one-time setup)
+pip install -e sls_build_backend
+
+# Build with --no-isolation (required because backend is local)
+python -m build --no-isolation
+```

SLS_Python/pyproject.toml

@@ -0,0 +1,20 @@
+# Build this file using 'python -m build --no-isolation'
+[build-system]
+requires = ["setuptools>=61.0", "wheel", "sls_build_backend"]
+build-backend = "sls_build_backend"
+
+[project]
+name = "sls_python"
+version = "0.0.2-alpha"
+description = "Python reimplementation of the SLS C project"
+authors = [ { name = "Kyler Olsen" } ]
+readme = "README.md"
+license = { text = "MIT" }
+requires-python = ">=3.10"
+dependencies = []
+
+[tool.setuptools]
+packages = ["sls_py"]
+
+[project.scripts]
+sls_py = "sls_py.__main__:main"

SLS_Python/sls_build_backend/__init__.py

@@ -0,0 +1,5 @@
+"""Build backend for sls_python package."""
+
+from .build_hooks import build_wheel, build_sdist
+
+__all__ = ["build_wheel", "build_sdist"]

SLS_Python/sls_build_backend/_version.py.in

@@ -0,0 +1,4 @@
+# Auto-generated during build
+version = "{version}"
+commit = "{commit}"
+timestamp = "{timestamp}"

SLS_Python/sls_build_backend/_version_dev.py.in

@@ -0,0 +1,23 @@
+import subprocess
+from datetime import datetime, timezone
+version = "{version}"
+try:
+    __result_hash = subprocess.check_output(
+        ["git", "describe", "--always", "--dirty", "--abbrev=7"],
+        cwd=".",
+        stderr=subprocess.DEVNULL,
+        text=True
+    ).strip()
+    __result_date = subprocess.check_output(
+        ["git", "show", "-s", "--format=%ci"],
+        cwd=".",
+        stderr=subprocess.DEVNULL,
+        text=True
+    ).strip()
+    commit = __result_hash + " " + __result_date
+except:
+    commit = "unknown"
+try:
+    timestamp = datetime.now(timezone.utc).isoformat() + "Z"
+except:
+    timestamp = "unknown"

SLS_Python/sls_build_backend/build_hooks.py

@@ -0,0 +1,17 @@
+from setuptools.build_meta import build_wheel as _build_wheel
+from setuptools.build_meta import build_sdist as _build_sdist
+from .write_version import generate_version, generate_version_dev
+
+
+def build_wheel(*args, **kwargs):
+    generate_version()
+    o = _build_wheel(*args, **kwargs)
+    generate_version_dev()
+    return o
+
+
+def build_sdist(*args, **kwargs):
+    generate_version()
+    o = _build_sdist(*args, **kwargs)
+    generate_version_dev()
+    return o

SLS_Python/sls_build_backend/pyproject.toml

@@ -0,0 +1,14 @@
+[build-system]
+requires = ["setuptools>=61.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "sls-build-backend"
+version = "0.1.0"
+description = "Build backend for sls_python"
+authors = [{name = "Kyler Olsen"}]
+requires-python = ">=3.10"
+
+[tool.setuptools]
+packages = ["sls_build_backend"]
+package-dir = {"" = ".."}

SLS_Python/sls_build_backend/write_version.py

@@ -0,0 +1,91 @@
+
+import subprocess
+import datetime
+import pathlib
+
+try:
+    import tomllib  # Python 3.11+
+except Exception:  # pragma: no cover - older Pythons
+    tomllib = None
+
+root = pathlib.Path(__file__).resolve().parents[1]
+# templates live inside the backend package
+template = root / "sls_build_backend" / "_version.py.in"
+template_dev = root / "sls_build_backend" / "_version_dev.py.in"
+output = root / "sls_py" / "_version.py"
+
+
+def get_commit():
+    try:
+        result_hash = subprocess.check_output(
+            ["git", "describe", "--always", "--dirty", "--abbrev=7"],
+            cwd=str(root),
+            stderr=subprocess.DEVNULL,
+            text=True,
+        ).strip()
+        result_date = subprocess.check_output(
+            ["git", "show", "-s", "--format=%ci"],
+            cwd=str(root),
+            stderr=subprocess.DEVNULL,
+            text=True,
+        ).strip()
+        return f"{result_hash} {result_date}"
+    except Exception:
+        return "unknown"
+
+
+def get_timestamp():
+    return datetime.datetime.now(datetime.timezone.utc).isoformat() + "Z"
+
+
+def _get_version_from_pyproject(root_path: pathlib.Path):
+    py = root_path / "pyproject.toml"
+    if not py.exists() or tomllib is None:
+        return None
+    try:
+        data = tomllib.loads(py.read_text())
+    except Exception:
+        return None
+    # PEP 621
+    version = data.get("project", {}).get("version")
+    if version:
+        return version
+    # Some projects put metadata under tool.setuptools
+    version = data.get("tool", {}).get("setuptools", {}).get("version")
+    return version
+
+
+def _determine_version(root_path: pathlib.Path):
+    v = _get_version_from_pyproject(root_path)
+    if v:
+        return v
+    return "unknown"
+
+
+def generate_version_dev():
+    version = _determine_version(root)
+    if not template_dev.exists():
+        # write a minimal generated file if dev template missing
+        output.write_text(f"version = \"{version}\"\ncommit = \"unknown\"\ntimestamp = \"unknown\"\n")
+        return
+    text = template_dev.read_text()
+    text = text.format(version=version)
+    output.write_text(text)
+
+
+def generate_version():
+    version = _determine_version(root)
+
+    commit = get_commit()
+    timestamp = get_timestamp()
+
+    if not template.exists():
+        # fallback: write a minimal file
+        output.write_text(
+            f"version = \"{version}\"\ncommit = \"{commit}\"\ntimestamp = \"{timestamp}\"\n"
+        )
+        return
+
+    text = template.read_text()
+    text = text.format(version=version, commit=commit, timestamp=timestamp)
+    output.write_text(text)

SLS_Python/sls_py.pyi

@@ -0,0 +1,142 @@
+from dataclasses import dataclass, field
+from enum import Enum, auto
+from typing import Callable, Dict, List, Optional
+
+def main() -> int:
+    ...
+
+SLS_NAME: str
+SLS_VERSION: str
+SLS_COMMIT: str
+INTERPRETER_NAME: str
+INTERPRETER_VER: int
+MODULE_TIMESTAMP: str
+SLS_INFO_STRING_1: str
+SLS_INFO_STRING_2: str
+
+
+class LexerInfo:
+    filename: str
+    source_code: str
+    pos: int
+    column: int
+    line: int
+
+    def __init__(self, filename: str = "", source_code: str = ""): ...
+
+
+class TokenType(Enum):
+    EOF = auto()
+    IDENTIFIER = auto()
+    INTEGER = auto()
+    FLOAT = auto()
+    DOUBLE = auto()
+    CHARACTER = auto()
+    STRING = auto()
+    BOOLEAN = auto()
+    ARRAY = auto()
+    TOKEN_STRING = auto()
+    TYPE_TUPLE = auto()
+
+
+@dataclass
+class Identifier:
+    name: str
+    is_literal: bool
+
+
+class IntegerBuiltInType(Enum):
+    I64 = auto()
+    I32 = auto()
+    I16 = auto()
+    I8 = auto()
+    U64 = auto()
+    U32 = auto()
+    U16 = auto()
+    U8 = auto()
+
+
+@dataclass
+class IntegerLiteral:
+    value: int
+    type: IntegerBuiltInType
+
+
+@dataclass
+class TokenString:
+    tokens: List["Token"] = field(default_factory=list)
+
+    def deep_copy(self) -> TokenString: ...
+
+
+@dataclass
+class Token:
+    type: TokenType
+    identifier: Optional[Identifier] = None
+    integer_literal: Optional[IntegerLiteral] = None
+    float_literal: Optional[float] = None
+    double_literal: Optional[float] = None
+    character_literal: Optional[int] = None
+    string_literal: Optional[str] = None
+    boolean_literal: Optional[bool] = None
+    token_string: Optional[TokenString] = None
+
+
+def lexical_analysis(lexer_info: LexerInfo) -> List[Token]:
+    ...
+
+
+class StackType(Enum):
+    IDENTIFIER = auto()
+    I64 = auto()
+    I32 = auto()
+    I16 = auto()
+    I8 = auto()
+    U64 = auto()
+    U32 = auto()
+    U16 = auto()
+    U8 = auto()
+    FLOAT = auto()
+    DOUBLE = auto()
+    CHARACTER = auto()
+    BOOLEAN = auto()
+    TOKEN_STRING = auto()
+    CALLABLE = auto()
+
+@dataclass
+class StackEntry:
+    type: StackType
+    value: object
+
+
+class FunctionType(Enum):
+    TOKEN_STRING = auto()
+    BUILTIN = auto()
+
+
+@dataclass
+class FunctionItem:
+    type: FunctionType
+    token_string: Optional[TokenString] = None
+    builtin: Optional[Callable[["InterpreterState"], bool]] = None
+
+    @classmethod
+    def from_token_string(cls, ts: TokenString) -> "FunctionItem": ...
+    @classmethod
+    def from_builtin(cls, fn: Callable[["InterpreterState"], bool]) -> "FunctionItem": ...
+
+
+class InterpreterState:
+    stack: List[StackEntry]
+    functions: Dict[str, FunctionItem]
+
+    def __init__(self): ...
+    def push(self, entry: StackEntry) -> None: ...
+    def pop(self) -> Optional[StackEntry]: ...
+    def top(self) -> Optional[StackEntry]: ...
+    def add_function(self, name: str, item: FunctionItem) -> None: ...
+    def get_function(self, name: str) -> Optional[FunctionItem]: ...
+    def push_token(self, token: Token) -> bool: ...
+    def execute_func(self, key: str) -> bool: ...
+    def execute_token_string(self, token_string: TokenString) -> bool: ...
+    def execute(self, token: Token) -> bool: ...

SLS_Python/sls_py/__init__.py

@@ -0,0 +1,56 @@
+from .__main__ import main
+
+from .meta import (
+    SLS_NAME,
+    SLS_VERSION,
+    SLS_COMMIT,
+    INTERPRETER_NAME,
+    INTERPRETER_VER,
+    MODULE_TIMESTAMP,
+    SLS_INFO_STRING_1,
+    SLS_INFO_STRING_2,
+)
+
+from .lexer import (
+    LexerInfo,
+    TokenType,
+    Identifier,
+    IntegerBuiltInType,
+    IntegerLiteral,
+    TokenString,
+    Token,
+    lexical_analysis,
+)
+
+from .interpreter import (
+    StackType,
+    StackEntry,
+    FunctionType,
+    FunctionItem,
+    InterpreterState,
+)
+
+__all__ = [
+    "main",
+    "SLS_NAME",
+    "SLS_VERSION",
+    "SLS_COMMIT",
+    "INTERPRETER_NAME",
+    "INTERPRETER_VER",
+    "MODULE_TIMESTAMP",
+    "SLS_INFO_STRING_1",
+    "SLS_INFO_STRING_2",
+    "LexerInfo",
+    "TokenType",
+    "Identifier",
+    "IntegerBuiltInType",
+    "IntegerLiteral",
+    "TokenString",
+    "Token",
+    "lexical_analysis",
+    "StackType",
+    "StackEntry",
+    "FunctionType",
+    "FunctionItem",
+    "InterpreterState",
+]

SLS_Python/sls_py/__main__.py

@@ -0,0 +1,33 @@
+import sys
+from .meta import print_version
+from .repl import repl
+from .file import run_file
+
+
+def main() -> int:
+    args = sys.argv[1:]
+
+    version = False
+    filename = None
+
+    if len(args) == 1:
+        if args[0] in ("--version", "-v"):
+            version = True
+        else:
+            filename = args[0]
+    elif len(args) > 1:
+        print("Too many arguments!")
+        return 1
+
+    if version:
+        print_version()
+        return 0
+
+    if filename is not None:
+        return run_file(filename)
+
+    return repl()
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

SLS_Python/sls_py/_version.py

@@ -0,0 +1,23 @@
+import subprocess
+from datetime import datetime, timezone
+version = "0.0.2-alpha"
+try:
+    __result_hash = subprocess.check_output(
+        ["git", "describe", "--always", "--dirty", "--abbrev=7"],
+        cwd=".",
+        stderr=subprocess.DEVNULL,
+        text=True
+    ).strip()
+    __result_date = subprocess.check_output(
+        ["git", "show", "-s", "--format=%ci"],
+        cwd=".",
+        stderr=subprocess.DEVNULL,
+        text=True
+    ).strip()
+    commit = __result_hash + " " + __result_date
+except:
+    commit = "unknown"
+try:
+    timestamp = datetime.now(timezone.utc).isoformat() + "Z"
+except:
+    timestamp = "unknown"

SLS_Python/sls_py/calc/__main__.py

@@ -0,0 +1,268 @@
+#!/usr/bin/env python3
+"""
+HP-Style RPN Calculator using Stack Language Backend
+Implements classic HP calculator interface with stack display
+"""
+
+import tkinter as tk
+from tkinter import ttk, font as tkfont
+from .. import (
+    InterpreterState,
+    LexerInfo,
+    lexical_analysis,
+    TokenType,
+    StackType,
+)
+
+class SlsCalculator:
+    def __init__(self, root):
+        self.root = root
+        self.root.title("SLS Calculator")
+        # self.root.geometry("450x650")
+        self.root.resizable(False, False)
+        
+        # Initialize interpreter
+        self.interp = InterpreterState()
+        self.lexer = LexerInfo()
+        
+        # Current entry buffer
+        self.entry_buffer = ""
+        self.is_new_entry = True
+        
+        # Set up UI
+        self.create_widgets()
+        
+    def create_widgets(self):
+        """Create all calculator widgets"""
+        # Main container
+        main_frame = ttk.Frame(self.root, padding="10")
+        main_frame.grid(row=0, column=0, sticky=(tk.W, tk.E, tk.N, tk.S)) # type: ignore
+        
+        self.create_stack_display(main_frame)
+        
+        # Entry display
+        self.create_entry_display(main_frame)
+        
+        # Button grid
+        self.create_button_grid(main_frame)
+        
+    def create_stack_display(self, parent):
+        """Create the 4-level stack display"""
+        stack_frame = ttk.LabelFrame(parent, text="Stack", padding="5")
+        stack_frame.grid(row=0, column=0, columnspan=4, sticky=(tk.W, tk.E), pady=(0, 10)) # type: ignore
+        
+        self.stack_labels = []
+        for i in range(4):
+            label = ttk.Label(stack_frame,
+                            text=f"{3-i}:",
+                            anchor='e',
+                            width=30)
+            label.grid(row=i, column=0, sticky=(tk.W, tk.E), pady=2) # type: ignore
+            self.stack_labels.append(label)
+            
+    def create_entry_display(self, parent):
+        """Create the current entry display"""
+        entry_frame = ttk.Frame(parent)
+        entry_frame.grid(row=1, column=0, columnspan=4, sticky=(tk.W, tk.E), pady=(0, 10)) # type: ignore
+        
+        self.entry_label = ttk.Label(entry_frame,
+                                    text="0",
+                                    anchor='e',
+                                    font=('Courier', 16))
+        self.entry_label.grid(row=0, column=0, sticky=(tk.W, tk.E)) # type: ignore
+        
+    def create_button_grid(self, parent):
+        """Create the calculator button grid"""
+        buttons = [
+            [('√', self.sqrt), ('x²', self.square), ('1/x', self.reciprocal), ('NULL', lambda: None)],
+            [('ENTER', lambda: self.enter(True)), ('SWAP', self.swap), ('<-', self.drop), ('NULL', lambda: None)],
+            [('7', lambda: self.digit('7')), ('8', lambda: self.digit('8')), ('9', lambda: self.digit('9')), ('÷', self.divide)],
+            [('4', lambda: self.digit('4')), ('5', lambda: self.digit('5')), ('6', lambda: self.digit('6')), ('×', self.multiply)],
+            [('1', lambda: self.digit('1')), ('2', lambda: self.digit('2')), ('3', lambda: self.digit('3')), ('−', self.subtract)],
+            [('0', lambda: self.digit('0')), ('.', self.decimal), ('±', self.negate), ('+', self.add)],
+        ]
+        
+        for row_idx, row in enumerate(buttons, start=2):
+            for col_idx, (text, command) in enumerate(row):
+                if text != "NULL":
+                    btn = ttk.Button(parent,
+                                    text=text,
+                                    command=command,
+                                    width=8)
+                    btn.grid(row=row_idx, column=col_idx, padx=2, pady=2, sticky=(tk.W, tk.E, tk.N, tk.S)) # type: ignore
+        
+        # Keyboard bindings
+        self.root.bind('<Delete>', lambda e: self.drop())
+        self.root.bind('<Return>', lambda e: self.enter(True))
+        self.root.bind('<KP_Enter>', lambda e: self.enter(True))
+        for i in range(10):
+            self.root.bind(str(i), lambda e, n=str(i): self.digit(n))
+        self.root.bind('.', lambda e: self.decimal())
+        self.root.bind('+', lambda e: self.add())
+        self.root.bind('-', lambda e: self.subtract())
+        self.root.bind('*', lambda e: self.multiply())
+        self.root.bind('/', lambda e: self.divide())
+        
+    def digit(self, d):
+        """Handle digit button press"""
+        if self.is_new_entry:
+            self.entry_buffer = d
+            self.is_new_entry = False
+        else:
+            self.entry_buffer += d
+        self.update_entry_display()
+        
+    def decimal(self):
+        """Handle decimal point"""
+        if self.is_new_entry:
+            self.entry_buffer = "0."
+            self.is_new_entry = False
+        elif '.' not in self.entry_buffer:
+            self.entry_buffer += '.'
+        self.update_entry_display()
+        
+    def negate(self):
+        """Toggle sign of current entry"""
+        if self.is_new_entry:
+            # Negate top of stack
+            self.execute_code("0 swap -")
+        else:
+            if self.entry_buffer.startswith('-'):
+                self.entry_buffer = self.entry_buffer[1:]
+            else:
+                self.entry_buffer = '-' + self.entry_buffer
+        self.update_entry_display()
+        
+    def enter(self, key=False):
+        """Push current entry onto stack"""
+        if self.entry_buffer:
+            self.execute_code(self.entry_buffer)
+            self.entry_buffer = ""
+            self.is_new_entry = True
+        elif key:
+            self.execute_code("dup")
+        self.update_displays()
+        
+    def add(self):
+        """Addition operation"""
+        self.enter()
+        self.execute_code("+")
+        self.update_displays()
+        
+    def subtract(self):
+        """Subtraction operation"""
+        self.enter()
+        self.execute_code("-")
+        self.update_displays()
+        
+    def multiply(self):
+        """Multiplication operation"""
+        self.enter()
+        self.execute_code("*")
+        self.update_displays()
+        
+    def divide(self):
+        """Division operation"""
+        self.enter()
+        self.execute_code("/")
+        self.update_displays()
+        
+    def sqrt(self):
+        """Square root operation"""
+        self.enter()
+        self.execute_code("sqrt")
+        self.update_displays()
+        
+    def square(self):
+        """Square operation"""
+        self.enter()
+        self.execute_code("dup *")
+        self.update_displays()
+        
+    def reciprocal(self):
+        """Reciprocal (1/x) operation"""
+        self.enter()
+        self.execute_code("1 swap /")
+        self.update_displays()
+        
+    def swap(self):
+        """Swap top two stack items"""
+        self.enter()
+        self.execute_code("swap")
+        self.update_displays()
+        
+    def drop(self):
+        """Drop top stack item"""
+        self.enter()
+        self.execute_code("drop")
+        self.update_displays()
+        
+    def execute_code(self, code):
+        """Execute stack language code"""
+        try:
+            self.lexer.source_code = code
+            self.lexer.pos = 0
+            self.lexer.column = 1
+            self.lexer.line = 1
+            
+            tokens = lexical_analysis(self.lexer)
+            
+            for token in tokens:
+                if token.type == TokenType.EOF:
+                    break
+                if not self.interp.execute(token):
+                    print(f"Error executing: {code}")
+                    break
+        except Exception as e:
+            print(f"Exception: {e}")
+            
+    def update_entry_display(self):
+        """Update the entry display"""
+        display_text = self.entry_buffer if self.entry_buffer else "0"
+        self.entry_label.config(text=display_text)
+        
+    def update_displays(self):
+        """Update both entry and stack displays"""
+        self.update_entry_display()
+        self.update_stack_display()
+        
+    def update_stack_display(self):
+        """Update the 4-level stack display"""
+        stack_size = len(self.interp.stack)
+        
+        for i in range(4):
+            level = 3 - i  # T3, T2, T1, T0
+            if stack_size > level:
+                entry = self.interp.stack[-(level + 1)]
+                value_str = self.format_stack_entry(entry)
+                self.stack_labels[i].config(text=f"{level}: {value_str}")
+            else:
+                self.stack_labels[i].config(text=f"{level}:")
+                
+    def format_stack_entry(self, entry):
+        """Format a stack entry for display"""
+        if entry.type == StackType.I64:
+            return str(entry.value)
+        elif entry.type == StackType.DOUBLE:
+            val = entry.value
+            # Format with appropriate precision
+            if abs(val) < 1e-10 and val != 0:
+                return f"{val:.6e}"
+            elif abs(val) > 1e10:
+                return f"{val:.6e}"
+            else:
+                return f"{val:.10g}"
+        elif entry.type == StackType.BOOLEAN:
+            return str(entry.value)
+        else:
+            return str(entry.value)
+
+
+def main():
+    root = tk.Tk()
+    app = SlsCalculator(root)
+    root.mainloop()
+
+
+if __name__ == "__main__":
+    main()

SLS_Python/sls_py/file.py

@@ -0,0 +1,37 @@
+from pathlib import Path
+from .lexer import LexerInfo, lexical_analysis, Token
+from .interpreter import InterpreterState
+
+
+def exec_file(interpreter_state: InterpreterState, filename: str) -> bool:
+    path = Path(filename)
+
+    if not path.exists():
+        print(f"Cannot read file: {filename}")
+        return False
+
+    try:
+        code = path.read_text()
+    except Exception:
+        print(f"Cannot read file: {filename}")
+        return False
+
+    lexer_info = LexerInfo(filename=filename, source_code=code)
+
+    tokens: list[Token] = lexical_analysis(lexer_info)
+
+    for tok in tokens:
+        if not interpreter_state.execute(tok):
+            print("A runtime error occurred!")
+            return False
+
+    return True
+
+def run_file(filename: str) -> int:
+    print(f"Executing file: {filename}")
+
+    interpreter_state = InterpreterState()
+
+    success = exec_file(interpreter_state, filename)
+
+    return 0 if success else 1

SLS_Python/sls_py/interpreter.py

@@ -0,0 +1,230 @@
+from __future__ import annotations
+from dataclasses import dataclass
+from enum import Enum, auto
+from typing import Callable, Dict, List, Optional
+
+from .lexer import (
+    Token,
+    TokenType,
+    TokenString,
+    IntegerLiteral,
+    IntegerBuiltInType,
+)
+
+from .interpreter_types import StackType
+from .builtin import load_builtins
+
+
+@dataclass
+class StackEntry:
+    type: StackType
+    value: object  # Identifier | int | float | bool | TokenString | FunctionItem etc.
+
+
+class FunctionType(Enum):
+    TOKEN_STRING = auto()
+    BUILTIN = auto()
+
+type FunctionData = TokenString | Callable[["InterpreterState"], bool]
+
+@dataclass
+class FunctionItem:
+    type: FunctionType
+    token_string: Optional[TokenString] = None
+    builtin: Optional[Callable[["InterpreterState"], bool]] = None
+
+    @classmethod
+    def from_item(cls, item: FunctionData) -> "FunctionItem":
+        if isinstance(item, TokenString):
+            return cls.from_token_string(item)
+        else:
+            return cls.from_builtin(item)
+
+    @classmethod
+    def from_token_string(cls, ts: TokenString) -> "FunctionItem":
+        return cls(type=FunctionType.TOKEN_STRING, token_string=ts)
+
+    @classmethod
+    def from_builtin(cls, fn: Callable[["InterpreterState"], bool]) -> "FunctionItem":
+        return cls(type=FunctionType.BUILTIN, builtin=fn)
+
+
+class InterpreterState:
+    """
+    Interpreter state holds:
+        - stack: list of StackEntry (top of stack is stack[-1])
+        - functions: dict mapping names to FunctionItem
+    """
+
+    def __init__(self):
+        self.stack: List[StackEntry] = []
+        self.functions: Dict[str, FunctionItem] = {}
+
+        if load_builtins is not None:
+            ok = load_builtins(self)
+            if not ok:
+                raise RuntimeError("Failed to load builtins")
+
+    # -------------------------
+    # stack helpers
+    # -------------------------
+    def push(self, entry: StackEntry) -> None:
+        self.stack.append(entry)
+
+    def pop(self) -> Optional[StackEntry]:
+        if not self.stack:
+            return None
+        return self.stack.pop()
+
+    def top(self) -> Optional[StackEntry]:
+        if not self.stack:
+            return None
+        return self.stack[-1]
+
+    # -------------------------
+    # function table
+    # -------------------------
+    def add_function(self, name: str, item: FunctionData) -> None:
+        self.functions[name] = FunctionItem.from_item(item)
+
+    def get_function(self, name: str) -> Optional[FunctionItem]:
+        return self.functions.get(name)
+
+    # -------------------------
+    # execution primitives
+    # -------------------------
+    def push_token(self, token: Token) -> bool:
+        """
+        Push a token onto the stack. Returns True on success, False on failure.
+        Mirrors the logic from the C implementation:
+            - disallow TOKEN_STRING, TOKEN_ARRAY, TOKEN_TYPE_TUPLE
+            - return True for TOKEN_EOF (no-op)
+        """
+        ttype = token.type
+
+        if ttype == TokenType.EOF:
+            return True
+
+        # map token -> stack type + extract value
+        if ttype == TokenType.IDENTIFIER:
+            entry = StackEntry(StackType.IDENTIFIER, token.identifier)
+            self.push(entry)
+            return True
+
+        if ttype == TokenType.INTEGER:
+            ilit: IntegerLiteral = token.integer_literal  # type: ignore
+            itype = ilit.type
+            # choose stack type explicitly to mirror C widths
+            if itype == IntegerBuiltInType.I64:
+                st = StackType.I64
+                val = int(ilit.value)
+            elif itype == IntegerBuiltInType.I32:
+                st = StackType.I32
+                val = int(ilit.value) & 0xFFFFFFFF  # mimic truncation if desired
+            elif itype == IntegerBuiltInType.I16:
+                st = StackType.I16
+                val = int(ilit.value) & 0xFFFF
+            elif itype == IntegerBuiltInType.I8:
+                st = StackType.I8
+                val = int(ilit.value) & 0xFF
+            elif itype == IntegerBuiltInType.U64:
+                st = StackType.U64
+                val = int(ilit.value)
+            elif itype == IntegerBuiltInType.U32:
+                st = StackType.U32
+                val = int(ilit.value) & 0xFFFFFFFF
+            elif itype == IntegerBuiltInType.U16:
+                st = StackType.U16
+                val = int(ilit.value) & 0xFFFF
+            elif itype == IntegerBuiltInType.U8:
+                st = StackType.U8
+                val = int(ilit.value) & 0xFF
+            else:
+                return False
+
+            self.push(StackEntry(st, val))
+            return True
+
+        if ttype == TokenType.FLOAT:
+            self.push(StackEntry(StackType.FLOAT, token.float_literal))
+            return True
+
+        if ttype == TokenType.DOUBLE:
+            self.push(StackEntry(StackType.DOUBLE, token.double_literal))
+            return True
+
+        if ttype == TokenType.CHARACTER:
+            self.push(StackEntry(StackType.CHARACTER, token.character_literal))
+            return True
+
+        if ttype == TokenType.STRING:
+            # C returned FALSE for TOKEN_STRING
+            return False
+
+        if ttype == TokenType.BOOLEAN:
+            self.push(StackEntry(StackType.BOOLEAN, token.boolean_literal))
+            return True
+
+        if ttype == TokenType.ARRAY:
+            # C returned FALSE for arrays
+            return False
+
+        if ttype == TokenType.TOKEN_STRING:
+            # copy token string to mimic C copy semantics
+            ts_copy = token.token_string.deep_copy()  # type: ignore
+            self.push(StackEntry(StackType.TOKEN_STRING, ts_copy))
+            return True
+
+        if ttype == TokenType.TYPE_TUPLE:
+            # C returned FALSE for type tuples
+            return False
+
+        # unknown token type
+        return False
+
+    def execute_func(self, key: str) -> bool:
+        """
+        Look up a function by name and execute it.
+        Builtin functions are callables that accept InterpreterState and return bool.
+        Token-string functions are executed via execute_token_string.
+        """
+        func = self.get_function(key)
+        if func is None:
+            return False
+
+        if func.type == FunctionType.BUILTIN:
+            if func.builtin is None:
+                return False
+            return func.builtin(self)
+
+        if func.type == FunctionType.TOKEN_STRING:
+            if func.token_string is None:
+                return False
+            return self.execute_token_string(func.token_string)
+
+        return False
+
+    def execute_token_string(self, token_string: TokenString) -> bool:
+        """
+        Execute each token in a TokenString.
+        If token is an identifier and not `is_literal`, treat it as a function call.
+        Otherwise push token onto the stack.
+        """
+        for tok in token_string.tokens:
+            if tok.type == TokenType.IDENTIFIER and tok.identifier is not None and not tok.identifier.is_literal:
+                rv = self.execute_func(tok.identifier.name)
+            else:
+                rv = self.push_token(tok)
+            if not rv:
+                return False
+        return True
+
+    def execute(self, token: Token) -> bool:
+        """
+        Execute a single Token (this corresponds to processing a single lexer result).
+        If the token is an un-literal identifier -> function call, otherwise push it.
+        """
+        if token.type == TokenType.IDENTIFIER and token.identifier is not None and not token.identifier.is_literal:
+            return self.execute_func(token.identifier.name)
+        else:
+            return self.push_token(token)

SLS_Python/sls_py/interpreter_types.py

@@ -0,0 +1,18 @@
+from enum import Enum, auto
+
+class StackType(Enum):
+    IDENTIFIER = auto()
+    I64 = auto()
+    I32 = auto()
+    I16 = auto()
+    I8 = auto()
+    U64 = auto()
+    U32 = auto()
+    U16 = auto()
+    U8 = auto()
+    FLOAT = auto()
+    DOUBLE = auto()
+    CHARACTER = auto()
+    BOOLEAN = auto()
+    TOKEN_STRING = auto()
+    CALLABLE = auto()

SLS_Python/sls_py/lexer.py

@@ -0,0 +1,904 @@
+from __future__ import annotations
+from dataclasses import dataclass, field
+from enum import Enum, auto
+from typing import List, Optional, Any, Union
+
+
+# =====================================================================
+#  Basic Types
+# =====================================================================
+
+class LexerInfo:
+    filename: str
+    source_code: str
+    pos: int
+    column: int
+    line: int
+
+    def __init__(self, filename: str = "", source_code: str = ""):
+        self.filename = filename
+        self.source_code = source_code
+        self.pos = 0
+        self.column = 1
+        self.line = 1
+
+
+# =====================================================================
+#  Token Types
+# =====================================================================
+
+class TokenType(Enum):
+    EOF = auto()
+    IDENTIFIER = auto()
+    INTEGER = auto()
+    FLOAT = auto()
+    DOUBLE = auto()
+    CHARACTER = auto()
+    STRING = auto()
+    BOOLEAN = auto()
+    ARRAY = auto()
+    TOKEN_STRING = auto()
+    TYPE_TUPLE = auto()
+
+
+# =====================================================================
+#  Array Literal Types
+# =====================================================================
+
+class ArrayType(Enum):
+    IDENTIFIER = auto()
+    I64 = auto()
+    I32 = auto()
+    I16 = auto()
+    I8 = auto()
+    U64 = auto()
+    U32 = auto()
+    U16 = auto()
+    U8 = auto()
+    FLOAT = auto()
+    DOUBLE = auto()
+    CHARACTER = auto()
+    STRING = auto()
+    BOOLEAN = auto()
+    STRUCT_INLINE = auto()
+
+
+# =====================================================================
+#  Identifier
+# =====================================================================
+
+@dataclass
+class Identifier:
+    name: str
+    is_literal: bool
+
+
+# =====================================================================
+#  Integer Literal Type
+# =====================================================================
+
+class IntegerBuiltInType(Enum):
+    I64 = auto()
+    I32 = auto()
+    I16 = auto()
+    I8 = auto()
+    U64 = auto()
+    U32 = auto()
+    U16 = auto()
+    U8 = auto()
+
+
+@dataclass
+class IntegerLiteral:
+    value: int
+    type: IntegerBuiltInType
+
+
+# =====================================================================
+#  TokenString, TypeTuple, StructInline
+# =====================================================================
+
+@dataclass
+class TokenString:
+    tokens: List["Token"] = field(default_factory=list)
+
+    def deep_copy(self) -> TokenString:
+        copied_tokens = [Token(
+            type=token.type,
+            identifier=token.identifier,
+            integer_literal=token.integer_literal,
+            float_literal=token.float_literal,
+            double_literal=token.double_literal,
+            character_literal=token.character_literal,
+            string_literal=token.string_literal,
+            boolean_literal=token.boolean_literal,
+            array_literal=token.array_literal.deep_copy() if token.array_literal else None,
+            token_string=token.token_string.deep_copy() if token.token_string else None,
+            type_tuple=token.type_tuple.deep_copy() if token.type_tuple else None
+        ) for token in self.tokens]
+        return TokenString(tokens=copied_tokens)
+
+
+@dataclass
+class TypeTuple:
+    input_identifiers: List[Identifier] = field(default_factory=list)
+    output_identifiers: List[Identifier] = field(default_factory=list)
+
+    def deep_copy(self) -> TypeTuple:
+        copied_input_ids = [Identifier(name=id.name, is_literal=id.is_literal) for id in self.input_identifiers]
+        copied_output_ids = [Identifier(name=id.name, is_literal=id.is_literal) for id in self.output_identifiers]
+        return TypeTuple(input_identifiers=copied_input_ids, output_identifiers=copied_output_ids)
+
+
+@dataclass
+class StructInline:
+    values: List[Any]
+    name: str
+
+
+# =====================================================================
+#  ArrayLiteral
+# =====================================================================
+
+@dataclass
+class ArrayLiteral:
+    type: ArrayType
+
+    identifiers: Optional[List[Identifier]] = None
+    integer_literals: Optional[List[int]] = None
+    float_literals: Optional[List[float]] = None
+    double_literals: Optional[List[float]] = None
+    character_literals: Optional[List[int]] = None
+    string_literals: Optional[List[str]] = None
+    boolean_literals: Optional[List[bool]] = None
+    token_strings: Optional[List[TokenString]] = None
+    type_tuples: Optional[List[TypeTuple]] = None
+    struct_inline: Optional[StructInline] = None
+
+    shape: Optional[List[int]] = None
+    dimensions: int = 0
+
+    def deep_copy(self) -> ArrayLiteral:
+        copied_array = ArrayLiteral(type=self.type, dimensions=self.dimensions, shape=list(self.shape) if self.shape else None)
+
+        if self.identifiers is not None:
+            copied_array.identifiers = [Identifier(name=id.name, is_literal=id.is_literal) for id in self.identifiers]
+        if self.integer_literals is not None:
+            copied_array.integer_literals = list(self.integer_literals)
+        if self.float_literals is not None:
+            copied_array.float_literals = list(self.float_literals)
+        if self.double_literals is not None:
+            copied_array.double_literals = list(self.double_literals)
+        if self.character_literals is not None:
+            copied_array.character_literals = list(self.character_literals)
+        if self.string_literals is not None:
+            copied_array.string_literals = list(self.string_literals)
+        if self.boolean_literals is not None:
+            copied_array.boolean_literals = list(self.boolean_literals)
+        if self.token_strings is not None:
+            copied_array.token_strings = [ts.deep_copy() for ts in self.token_strings]
+        if self.type_tuples is not None:
+            copied_array.type_tuples = [tt.deep_copy() for tt in self.type_tuples]
+        if self.struct_inline is not None:
+            copied_array.struct_inline = StructInline(
+                values=list(self.struct_inline.values),
+                name=self.struct_inline.name
+            )
+
+        return copied_array
+
+
+# =====================================================================
+#  Token
+# =====================================================================
+
+@dataclass
+class Token:
+    type: TokenType
+
+    identifier: Optional[Identifier] = None
+    integer_literal: Optional[IntegerLiteral] = None
+    float_literal: Optional[float] = None
+    double_literal: Optional[float] = None
+    character_literal: Optional[int] = None
+    string_literal: Optional[str] = None
+    boolean_literal: Optional[bool] = None
+    array_literal: Optional[ArrayLiteral] = None
+    token_string: Optional[TokenString] = None
+    type_tuple: Optional[TypeTuple] = None
+
+
+# =====================================================================
+#  File Info and Results
+# =====================================================================
+
+@dataclass
+class FileInfo:
+    filename: str
+    line: int
+    column: int
+    length: int = 0
+    lines: int = 0
+
+
+@dataclass
+class LexerError(Exception):
+    message: str
+    file_info: FileInfo
+
+
+# =====================================================================
+#  Numeric Type Flags
+# =====================================================================
+
+class NumericType(Enum):
+    F64 = auto()
+    F32 = auto()
+    I64 = auto()
+    I32 = auto()
+    I16 = auto()
+    I8 = auto()
+    U64 = auto()
+    U32 = auto()
+    U16 = auto()
+    U8 = auto()
+
+
+class NumericLiteralType(Enum):
+    BINARY = auto()
+    OCTAL = auto()
+    DECIMAL = auto()
+    HEXADECIMAL = auto()
+    FLOAT = auto()
+    EXPONENTIAL = auto()
+
+
+# =====================================================================
+#  Lexer Implementation
+# =====================================================================
+
+class Lexer:
+    def __init__(self, info: LexerInfo):
+        self.info = info
+
+    def peek(self) -> str:
+        if self.info.pos >= len(self.info.source_code):
+            return '\0'
+        return self.info.source_code[self.info.pos]
+
+    def far_peek(self, offset: int) -> str:
+        pos = self.info.pos + offset
+        if pos >= len(self.info.source_code):
+            return '\0'
+        return self.info.source_code[pos]
+
+    def seek(self, index: int) -> str:
+        if index >= len(self.info.source_code):
+            return '\0'
+        return self.info.source_code[index]
+
+    def advance(self) -> str:
+        if self.info.pos < len(self.info.source_code):
+            if self.info.source_code[self.info.pos] == '\n':
+                self.info.line += 1
+                self.info.column = 1
+            else:
+                self.info.column += 1
+            self.info.pos += 1
+        return self.peek()
+
+    def get_file_info(self, start: int, start_line: int) -> FileInfo:
+        return FileInfo(
+            filename=self.info.filename,
+            line=self.info.line,
+            column=self.info.column,
+            length=self.info.pos - start,
+            lines=self.info.line - start_line
+        )
+
+    def get_token_text(self, start: int) -> str:
+        return self.info.source_code[start:self.info.pos]
+
+    def skip_comments_and_whitespace(self):
+        while True:
+            c = self.peek()
+            
+            # Skip comments
+            if (c == '/' and self.far_peek(1) == '/') or c == '#':
+                while self.peek() not in ('\n', '\0'):
+                    c = self.advance()
+            
+            # Skip whitespace
+            if c.isspace():
+                self.advance()
+                continue
+            
+            break
+
+    def is_identifier_continue(self, c: str) -> bool:
+        if not c.isprintable():
+            return False
+        if c == '/' and self.far_peek(1) == '/':
+            return False
+        if c in '{}[]()\'\"#':
+            return False
+        if c.isspace() or c == '\0':
+            return False
+        return True
+
+    def is_identifier_start(self) -> bool:
+        c = self.peek()
+        if c == ':' and self.far_peek(1) == ':':
+            c = self.far_peek(2)
+        return not c.isdigit() and self.is_identifier_continue(c)
+
+    # =====================================================================
+    #  Integer Parsing Helpers
+    # =====================================================================
+
+    def create_binary_integer(self, start: int) -> int:
+        token = self.get_token_text(start)
+        negative = token[0] == '-'
+        i = 3 if negative else 2
+        
+        value = 0
+        while i < len(token):
+            c = token[i]
+            if c.isspace() or c in '/:' or c == '\0':
+                break
+            if c in '._':
+                i += 1
+                continue
+            value *= 2
+            if c == '1':
+                value += 1
+            i += 1
+        
+        if negative:
+            # Python handles negative integers naturally
+            value = -value
+        return value
+
+    def create_octal_integer(self, start: int) -> int:
+        token = self.get_token_text(start)
+        negative = token[0] == '-'
+        i = 3 if negative else 2
+        
+        value = 0
+        while i < len(token):
+            c = token[i]
+            if c.isspace() or c in '/:' or c == '\0':
+                break
+            if c in '._':
+                i += 1
+                continue
+            value *= 8
+            if c.isdigit() and c < '8':
+                value += int(c)
+            i += 1
+        
+        if negative:
+            value = -value
+        return value
+
+    def create_decimal_integer(self, start: int) -> int:
+        token = self.get_token_text(start)
+        negative = token[0] == '-'
+        i = 1 if negative else 0
+        
+        value = 0
+        while i < len(token):
+            c = token[i]
+            if c.isspace() or c in '/:' or c == '\0':
+                break
+            if c == '_':
+                i += 1
+                continue
+            if c.isdigit():
+                value *= 10
+                value += int(c)
+            i += 1
+        
+        if negative:
+            value = -value
+        return value
+
+    def create_hexadecimal_integer(self, start: int) -> int:
+        token = self.get_token_text(start)
+        negative = token[0] == '-'
+        i = 3 if negative else 2
+        
+        value = 0
+        while i < len(token):
+            c = token[i]
+            if c.isspace() or c in '/:' or c == '\0':
+                break
+            if c in '._':
+                i += 1
+                continue
+            value *= 16
+            if c.isdigit():
+                value += int(c)
+            elif c.upper() in 'ABCDEF':
+                value += ord(c.upper()) - ord('A') + 10
+            i += 1
+        
+        if negative:
+            value = -value
+        return value
+
+    def create_float(self, start: int) -> float:
+        token = self.get_token_text(start)
+        negative = token[0] == '-'
+        i = 1 if negative else 0
+        
+        value = 0.0
+        fractional = 0
+        
+        while i < len(token):
+            c = token[i]
+            if c.isspace() or c in '/:' or c == '\0':
+                break
+            if c == '_':
+                i += 1
+                continue
+            if c == '.':
+                fractional = 1
+                i += 1
+                continue
+            
+            if fractional == 0:
+                value *= 10
+            else:
+                fractional *= 10
+            
+            if c.isdigit():
+                digit = int(c)
+                if fractional == 0:
+                    value += digit
+                else:
+                    value += digit / fractional
+            i += 1
+        
+        if negative:
+            value = -value
+        return value
+
+    # =====================================================================
+    #  Integer Type Validation
+    # =====================================================================
+
+    def get_integer_type(self, numeric_type: NumericType) -> IntegerBuiltInType:
+        type_map = {
+            NumericType.I64: IntegerBuiltInType.I64,
+            NumericType.I32: IntegerBuiltInType.I32,
+            NumericType.I16: IntegerBuiltInType.I16,
+            NumericType.I8: IntegerBuiltInType.I8,
+            NumericType.U64: IntegerBuiltInType.U64,
+            NumericType.U32: IntegerBuiltInType.U32,
+            NumericType.U16: IntegerBuiltInType.U16,
+            NumericType.U8: IntegerBuiltInType.U8,
+        }
+        
+        if numeric_type not in type_map:
+            raise ValueError("Encountered a Float where there should not be one.")
+        
+        return type_map[numeric_type]
+
+    def validate_integer_range(self, value: int, int_type: IntegerBuiltInType, start: int, start_line: int):
+        ranges = {
+            IntegerBuiltInType.I64: (-2**63, 2**63 - 1),
+            IntegerBuiltInType.I32: (-2**31, 2**31 - 1),
+            IntegerBuiltInType.I16: (-2**15, 2**15 - 1),
+            IntegerBuiltInType.I8: (-2**7, 2**7 - 1),
+            IntegerBuiltInType.U64: (0, 2**64 - 1),
+            IntegerBuiltInType.U32: (0, 2**32 - 1),
+            IntegerBuiltInType.U16: (0, 2**16 - 1),
+            IntegerBuiltInType.U8: (0, 2**8 - 1),
+        }
+        
+        min_val, max_val = ranges[int_type]
+        if value < min_val or value > max_val:
+            type_name = int_type.name.lower()
+            raise LexerError(
+                f"Integer overflow: value exceeds range for {type_name}.",
+                self.get_file_info(start, start_line)
+            )
+
+    def create_integer_token(self, int_type: IntegerBuiltInType, value: int, start: int, start_line: int) -> Token:
+        self.validate_integer_range(value, int_type, start, start_line)
+        return Token(
+            type=TokenType.INTEGER,
+            integer_literal=IntegerLiteral(value=value, type=int_type)
+        )
+
+    def create_float_token(self, numeric_type: NumericType, start: int, start_line: int) -> Token:
+        value = self.create_float(start)
+        if numeric_type == NumericType.F64:
+            return Token(type=TokenType.DOUBLE, double_literal=value)
+        else:
+            return Token(type=TokenType.FLOAT, float_literal=value)
+
+    # =====================================================================
+    #  Numeric Type Parsing
+    # =====================================================================
+
+    def parse_numeric_type(self, start: int, start_line: int, literal_type: NumericLiteralType) -> NumericType:
+        c = self.advance()
+        
+        if c == 'f':
+            if literal_type not in (NumericLiteralType.DECIMAL, NumericLiteralType.FLOAT, NumericLiteralType.EXPONENTIAL):
+                raise LexerError("Invalid numeric literal: float type not allowed.", self.get_file_info(start, start_line))
+            
+            c = self.advance()
+            if c == '6' and self.far_peek(1) == '4':
+                self.advance()
+                self.advance()
+                return NumericType.F64
+            elif c == '3' and self.far_peek(1) == '2':
+                self.advance()
+                self.advance()
+                return NumericType.F32
+            else:
+                raise LexerError("Invalid float type: must be of type 'f64' or 'f32'.", self.get_file_info(start, start_line))
+        
+        elif c in 'iu':
+            if literal_type in (NumericLiteralType.FLOAT, NumericLiteralType.EXPONENTIAL):
+                raise LexerError("Invalid float type: must be of type 'f64' or 'f32'.", self.get_file_info(start, start_line))
+            
+            unsigned = c == 'u'
+            c = self.advance()
+            
+            if c == '6' and self.far_peek(1) == '4':
+                self.advance()
+                self.advance()
+                return NumericType.U64 if unsigned else NumericType.I64
+            elif c == '3' and self.far_peek(1) == '2':
+                self.advance()
+                self.advance()
+                return NumericType.U32 if unsigned else NumericType.I32
+            elif c == '1' and self.far_peek(1) == '6':
+                self.advance()
+                self.advance()
+                return NumericType.U16 if unsigned else NumericType.I16
+            elif c == '8':
+                self.advance()
+                return NumericType.U8 if unsigned else NumericType.I8
+            else:
+                prefix = 'unsigned' if unsigned else 'signed'
+                raise LexerError(f"Invalid {prefix} integer type.", self.get_file_info(start, start_line))
+        
+        else:
+            raise LexerError("Invalid numeric type: type must start with 'f', 'i', or 'u'.", self.get_file_info(start, start_line))
+
+    # =====================================================================
+    #  Numeric Literal Parsing
+    # =====================================================================
+
+    def parse_binary_integer(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        while c in '01_':
+            c = self.advance()
+        
+        if c == ':':
+            numeric_type = self.parse_numeric_type(start, start_line, NumericLiteralType.BINARY)
+            int_type = self.get_integer_type(numeric_type)
+            value = self.create_binary_integer(start)
+            return self.create_integer_token(int_type, value, start, start_line)
+        
+        if c.isspace() or c in '/\0':
+            value = self.create_binary_integer(start)
+            return self.create_integer_token(IntegerBuiltInType.I64, value, start, start_line)
+        
+        raise LexerError(f"Invalid binary literal: unexpected '{c}' in binary integer.", self.get_file_info(start, start_line))
+
+    def parse_octal_integer(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        while c.isdigit() and c not in '89' or c == '_':
+            c = self.advance()
+        
+        if c == ':':
+            numeric_type = self.parse_numeric_type(start, start_line, NumericLiteralType.OCTAL)
+            int_type = self.get_integer_type(numeric_type)
+            value = self.create_octal_integer(start)
+            return self.create_integer_token(int_type, value, start, start_line)
+        
+        if c.isspace() or c in '/\0':
+            value = self.create_octal_integer(start)
+            return self.create_integer_token(IntegerBuiltInType.I64, value, start, start_line)
+        
+        raise LexerError(f"Invalid octal literal: unexpected '{c}' in octal integer.", self.get_file_info(start, start_line))
+
+    def parse_hexadecimal_integer(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        while c in '0123456789ABCDEFabcdef_':
+            c = self.advance()
+        
+        if c == ':':
+            numeric_type = self.parse_numeric_type(start, start_line, NumericLiteralType.HEXADECIMAL)
+            int_type = self.get_integer_type(numeric_type)
+            value = self.create_hexadecimal_integer(start)
+            return self.create_integer_token(int_type, value, start, start_line)
+        
+        if c.isspace() or c in '/\0':
+            value = self.create_hexadecimal_integer(start)
+            return self.create_integer_token(IntegerBuiltInType.I64, value, start, start_line)
+        
+        raise LexerError(f"Invalid hexadecimal literal: unexpected '{c}' in hexadecimal integer.", self.get_file_info(start, start_line))
+
+    def parse_exponential(self, start: int, start_line: int) -> Token:
+        raise NotImplementedError("Float exponential not implemented yet.")
+
+    def parse_float(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        while c.isdigit() or c == '_':
+            c = self.advance()
+        
+        if c in 'eE':
+            return self.parse_exponential(start, start_line)
+        
+        if c == ':':
+            numeric_type = self.parse_numeric_type(start, start_line, NumericLiteralType.FLOAT)
+            return self.create_float_token(numeric_type, start, start_line)
+        
+        if c.isspace() or c in '/\0':
+            return self.create_float_token(NumericType.F64, start, start_line)
+        
+        raise LexerError(f"Invalid float literal: unexpected '{c}' in float.", self.get_file_info(start, start_line))
+
+    def parse_decimal_integer(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        while c.isdigit() or c == '_':
+            c = self.advance()
+        
+        if c == '.':
+            self.advance()
+            return self.parse_float(start, start_line)
+        
+        if c in 'eE':
+            return self.parse_exponential(start, start_line)
+        
+        if c == ':':
+            numeric_type = self.parse_numeric_type(start, start_line, NumericLiteralType.DECIMAL)
+            int_type = self.get_integer_type(numeric_type)
+            value = self.create_decimal_integer(start)
+            return self.create_integer_token(int_type, value, start, start_line)
+        
+        if c.isspace() or c in '/\0':
+            value = self.create_decimal_integer(start)
+            return self.create_integer_token(IntegerBuiltInType.I64, value, start, start_line)
+        
+        raise LexerError(f"Invalid decimal literal: unexpected '{c}' in decimal integer.", self.get_file_info(start, start_line))
+
+    def parse_numeric_literal(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        if c == '-':
+            c = self.advance()
+        
+        if c == '0':
+            c = self.advance()
+            if c in 'bB':
+                self.advance()
+                return self.parse_binary_integer(start, start_line)
+            elif c in 'oO':
+                self.advance()
+                return self.parse_octal_integer(start, start_line)
+            elif c in 'xX':
+                self.advance()
+                return self.parse_hexadecimal_integer(start, start_line)
+        
+        return self.parse_decimal_integer(start, start_line)
+
+    # =====================================================================
+    #  Character Literal Parsing
+    # =====================================================================
+
+    def parse_character_literal(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        
+        if c == '\'':
+            raise LexerError("Invalid character literal: empty character literal.", self.get_file_info(start, start_line))
+        
+        if c == '\\':
+            c = self.advance()
+            escape_map = {
+                'n': '\n',
+                'r': '\r',
+                't': '\t',
+                '\\': '\\',
+                '\'': '\'',
+                '0': '\0'
+            }
+            if c in escape_map:
+                value = ord(escape_map[c])
+            else:
+                raise LexerError(f"Invalid character literal: unknown escape sequence '\\{c}'.", self.get_file_info(start, start_line))
+        elif c in '\n\r':
+            raise LexerError("Invalid character literal: unclosed character literal.", self.get_file_info(start, start_line))
+        else:
+            value = ord(c)
+        
+        c = self.advance()
+        
+        if c.isspace() or c in '/\0':
+            raise LexerError("Invalid character literal: unclosed character literal.", self.get_file_info(start, start_line))
+        elif c != '\'':
+            raise LexerError(f"Invalid character literal: unexpected '{c}' in character.", self.get_file_info(start, start_line))
+        
+        self.advance()
+        return Token(type=TokenType.CHARACTER, character_literal=value)
+
+    # =====================================================================
+    #  String Literal Parsing (stub)
+    # =====================================================================
+
+    def parse_string_literal(self, start: int, start_line: int) -> Token:
+        raise NotImplementedError("String literals not implemented yet.")
+
+    # =====================================================================
+    #  Token String Parsing
+    # =====================================================================
+
+    def parse_token_string(self, start: int, start_line: int) -> Token:
+        tokens = []
+        self.advance()  # Skip opening '{'
+        
+        watchdog = 0
+        while self.peek() != '\0':
+            self.skip_comments_and_whitespace()
+            c = self.peek()
+            
+            if c == '}':
+                self.advance()
+                return Token(type=TokenType.TOKEN_STRING, token_string=TokenString(tokens=tokens))
+            
+            token = self.lexer_next()
+            tokens.append(token)
+            
+            if token.type == TokenType.EOF:
+                break
+            
+            watchdog += 1
+            if watchdog > 1000000:
+                raise LexerError("Watchdog triggered in token string.", self.get_file_info(start, start_line))
+        
+        raise LexerError("Unclosed token string: missing closing brace '}'.", self.get_file_info(start, start_line))
+
+    # =====================================================================
+    #  Array and Type Tuple Parsing (stubs)
+    # =====================================================================
+
+    def parse_array_literal(self, start: int, start_line: int) -> Token:
+        raise NotImplementedError("Array literals not implemented yet.")
+
+    def parse_type_tuple(self, start: int, start_line: int) -> Token:
+        raise NotImplementedError("Type tuples not implemented yet.")
+
+    # =====================================================================
+    #  Identifier and Boolean Parsing
+    # =====================================================================
+
+    def parse_identifiers_and_booleans(self, start: int, start_line: int) -> Token:
+        c = self.peek()
+        is_literal = False
+        
+        # Check for identifier literal (::)
+        if c == ':' and self.far_peek(1) == ':':
+            is_literal = True
+            self.advance()
+            self.advance()
+            c = self.peek()
+        
+        # Read identifier name
+        name_chars = []
+        while self.is_identifier_continue(c):
+            if c == ':':
+                raise LexerError("Invalid identifier: ':' is not allowed in identifiers.", self.get_file_info(start, start_line))
+            if c == '.':
+                raise LexerError("Invalid identifier: '.' is not allowed in identifiers.", self.get_file_info(start, start_line))
+            name_chars.append(c)
+            c = self.advance()
+        
+        name = ''.join(name_chars)
+        
+        # Check for boolean literals
+        if name == 'false':
+            return Token(type=TokenType.BOOLEAN, boolean_literal=False)
+        elif name == 'true':
+            return Token(type=TokenType.BOOLEAN, boolean_literal=True)
+        else:
+            return Token(type=TokenType.IDENTIFIER, identifier=Identifier(name=name, is_literal=is_literal))
+
+    # =====================================================================
+    #  Main Lexer Logic
+    # =====================================================================
+
+    def lexer_next(self) -> Token:
+        self.skip_comments_and_whitespace()
+        
+        c = self.peek()
+        start = self.info.pos
+        start_line = self.info.line
+        
+        # End of file
+        if c == '\0':
+            return Token(type=TokenType.EOF)
+        
+        # Numeric literals (integers and floats)
+        if c.isdigit() or (c == '.' and self.far_peek(1).isdigit()) or (c == '-' and self.far_peek(1).isdigit()):
+            return self.parse_numeric_literal(start, start_line)
+        
+        # Character literals
+        if c == '\'':
+            self.advance()
+            return self.parse_character_literal(start, start_line)
+        
+        # String literals
+        if c == '"':
+            return self.parse_string_literal(start, start_line)
+        
+        # Token strings
+        if c == '{':
+            return self.parse_token_string(start, start_line)
+        
+        if c == '}':
+            self.advance()
+            raise LexerError("Unexpected closing brace '}' without matching opening brace.", self.get_file_info(start, start_line))
+        
+        # Array literals
+        if c == '[':
+            return self.parse_array_literal(start, start_line)
+        
+        if c == ']':
+            self.advance()
+            raise LexerError("Unexpected closing bracket ']' without matching opening bracket.", self.get_file_info(start, start_line))
+        
+        # Type tuples
+        if c == '(':
+            return self.parse_type_tuple(start, start_line)
+        
+        if c == ')':
+            self.advance()
+            raise LexerError("Unexpected closing parentheses ')' without matching opening parentheses.", self.get_file_info(start, start_line))
+        
+        # Identifiers and booleans
+        if self.is_identifier_start():
+            return self.parse_identifiers_and_booleans(start, start_line)
+        
+        # Check for malformed identifier literal
+        if c == ':':
+            self.advance()
+            if self.far_peek(1) == ':':
+                raise LexerError("Invalid identifier literal: empty identifier after '::'.", self.get_file_info(start, start_line))
+            else:
+                raise LexerError("Unexpected single colon ':'.", self.get_file_info(start, start_line))
+        
+        # Unknown character
+        raise LexerError(f"Unexpected character: unexpected '{c}' during parsing.", self.get_file_info(start, start_line))
+
+    def lexical_analysis(self) -> List[Token]:
+        """Main entry point for lexical analysis."""
+        tokens = []
+        
+        while True:
+            try:
+                token = self.lexer_next()
+                tokens.append(token)
+                
+                if token.type == TokenType.EOF:
+                    break
+            except LexerError as e:
+                # Re-raise lexer errors
+                raise
+        
+        return tokens
+
+
+# =====================================================================
+#  Public API
+# =====================================================================
+
+def lexical_analysis(lexer_info: LexerInfo) -> List[Token]:
+    """Convenience function matching the original C API."""
+    lexer = Lexer(lexer_info)
+    return lexer.lexical_analysis()

SLS_Python/sls_py/meta.py

@@ -0,0 +1,25 @@
+import sys
+try:
+    from ._version import version, commit, timestamp # type: ignore
+except ImportError:
+    version = "unknown"
+    commit = "unknown"
+    timestamp = "unknown"
+
+
+SLS_NAME = "SLS_PYTHON"
+SLS_VERSION = version
+SLS_COMMIT = commit
+
+# Runtime interpreter info (Python equivalent of compiler)
+_impl = sys.implementation
+INTERPRETER_NAME = _impl.name.capitalize()
+INTERPRETER_VER = _impl.version.major
+MODULE_TIMESTAMP = timestamp
+
+SLS_INFO_STRING_1 = f"YREA SLS ({SLS_NAME}) {SLS_VERSION} ({SLS_COMMIT})"
+SLS_INFO_STRING_2 = f"Running on {INTERPRETER_NAME} {INTERPRETER_VER} at {MODULE_TIMESTAMP}"
+
+def print_version() -> None:
+    print(SLS_INFO_STRING_1)
+    print(SLS_INFO_STRING_2)

SLS_Python/sls_py/repl.py

@@ -0,0 +1,83 @@
+from .meta import print_version
+from .lexer import LexerInfo, lexical_analysis
+from .interpreter import InterpreterState, StackType
+
+
+REPL_FILE_NAME = "<STDIN>"
+
+
+def print_top_of_stack(interpreter: InterpreterState) -> None:
+    """Pretty-print top of the stack."""
+
+    item = interpreter.top()
+    if item is None:
+        print("#0: <STACK IS EMPTY>")
+        return
+
+    t = item.type
+
+    if t == StackType.IDENTIFIER:
+        print(f"#0: ::{item.value}")
+    elif t == StackType.I64:
+        print(f"#0: {item.value}")
+    elif t in {StackType.I32, StackType.I16, StackType.I8}:
+        print(f"#0: {item.value}:{t}")
+    elif t in {StackType.U64, StackType.U32, StackType.U16, StackType.U8}:
+        print(f"#0: {item.value}:{t}")
+    elif t == StackType.FLOAT:
+        print(f"#0: {item.value}:f32")
+    elif t == StackType.DOUBLE:
+        print(f"#0: {item.value}")
+    elif t == StackType.CHARACTER:
+        print(f"#0: {item.value}")
+    elif t == StackType.BOOLEAN:
+        print("#0: TRUE" if item.value else "#0: FALSE")
+    elif t == StackType.TOKEN_STRING:
+        print("#0: <TOKEN STRING>")
+    elif t == StackType.CALLABLE:
+        print("#0: <CALLABLE>")
+    else:
+        print(f"#0: <UNKNOWN {t}>")
+
+
+def repl() -> int:
+    """Interactive interpreter loop."""
+
+    print_version()
+    print("===== YREA SLS REPL =====")
+    print("Type `#exit` to exit.")
+
+    interpreter = InterpreterState()
+
+    while True:
+        try:
+            line = input("> ")
+        except EOFError:
+            break
+
+        if line.strip() == "#exit":
+            return 0
+
+        # Create a fresh lexer each iteration
+        lexer_info = LexerInfo(filename=REPL_FILE_NAME, source_code=line)
+
+        try:
+            tokens = lexical_analysis(lexer_info)
+        except Exception as err:
+            print(err)
+            continue
+
+        # Execute tokens in order
+        for token in tokens:
+            try:
+                ok = interpreter.execute(token)
+                if not ok:
+                    print("A runtime error occurred!")
+                    break
+            except Exception as err:
+                print(err)
+                break
+
+        print_top_of_stack(interpreter)
+
+    return 1

SLS_Rust/README.md

@@ -0,0 +1,3 @@
+# SLS Rust
+
+This is the Rust implementation for the YREA SLS interpreter.

SLS_Rust/sls/.gitignore

@@ -0,0 +1,3 @@
+/target
+**/*.rs.bk
+Cargo.lock

SLS_Rust/sls/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "sls_rs"
+version = "0.0.2-alpha"
+edition = "2021"
+
+[dependencies]
+bitflags = "2.4"
+rand = "0.8"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+
+[build-dependencies]
+rustc_version = "0.4"
+chrono = "0.4"
+vergen = { version = "8", features = ["build"] }

SLS_Rust/sls/build.rs

@@ -0,0 +1,45 @@
+use std::process::Command;
+use vergen::EmitBuilder;
+
+fn try_cmd(cmd: &mut Command) -> Option<String> {
+    let out = cmd.output().ok()?;
+    if !out.status.success() {
+        return None;
+    }
+    Some(String::from_utf8_lossy(&out.stdout).trim().to_string())
+}
+
+fn main() {
+    // Emit all default vergen build info (BUILD_DATE / BUILD_TIME, etc.)
+    EmitBuilder::builder().all_build();
+
+    // Git describe + commit date (matches your Python logic)
+    let commit_info = (|| {
+        let hash = try_cmd(
+            Command::new("git")
+                .arg("describe")
+                .arg("--always")
+                .arg("--dirty")
+                .arg("--abbrev=7"),
+        )?;
+
+        let date = try_cmd(
+            Command::new("git")
+                .arg("show")
+                .arg("-s")
+                .arg("--format=%ci"),
+        )?;
+
+        Some(format!("{} {}", hash, date))
+    })()
+    .unwrap_or_else(|| "unknown".into());
+
+    println!("cargo:rustc-env=GIT_COMMIT_HASH={}", commit_info);
+
+    // Compiler info
+    println!("cargo:rustc-env=COMPILER_NAME=rustc");
+
+    let rustc_ver = try_cmd(Command::new("rustc").arg("--version"))
+        .unwrap_or_else(|| "unknown".into());
+    println!("cargo:rustc-env=COMPILER_VER={}", rustc_ver);
+}

SLS_Rust/sls/src/file.rs

@@ -0,0 +1,52 @@
+use std::fs;
+
+use crate::interpreter::InterpreterState;
+use crate::lexer::{LexerInfo, lexical_analysis, LexResult};
+
+/// Execute the contents of a script file.
+pub fn exec_file(interpreter: &mut InterpreterState, filename: &str) -> bool {
+    // Read the whole file
+    let source = match fs::read_to_string(filename) {
+        Ok(s) => s,
+        Err(e) => {
+            eprintln!("Cannot read file: {} ({})", filename, e);
+            return false;
+        }
+    };
+
+    let mut lexer_info = LexerInfo::new(filename, source.clone());
+
+    let result = lexical_analysis(&mut lexer_info);
+
+    match result {
+        LexResult::Ok(tokens) => {
+            for token in tokens {
+                if !interpreter.execute(&token) {
+                    return false;
+                }
+            }
+            true
+        }
+
+        LexResult::Err(err) => {
+            dbg!(err);
+            false
+        }
+    }
+}
+
+/// Stand-alone file execution entry point.
+pub fn run_file(filename: &str) -> i32 {
+    println!("Executing file: {}", filename);
+
+    let mut interpreter = InterpreterState::new();
+    if !interpreter.init() {
+        return 1;
+    }
+
+    if exec_file(&mut interpreter, filename) {
+        0
+    } else {
+        1
+    }
+}

SLS_Rust/sls/src/interpreter.rs

@@ -0,0 +1,170 @@
+use std::collections::HashMap;
+use serde::{Serialize, Deserialize};
+
+use crate::lexer::*; // Identifier, Token, TokenString, etc.
+use crate::builtin::{lookup_builtin, load_builtins};
+
+pub type BuiltinFn = fn(&mut InterpreterState) -> bool;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum StackValue {
+    Identifier(Identifier),
+
+    I64(i64),
+    I32(i32),
+    I16(i16),
+    I8(i8),
+
+    U64(u64),
+    U32(u32),
+    U16(u16),
+    U8(u8),
+
+    F32(f32),
+    F64(f64),
+
+    Character(u8),
+    Boolean(bool),
+
+    TokenString(TokenString),
+
+    Callable(TokenString),
+}
+
+#[derive(Debug, Clone)]
+pub struct BuiltinFunction {
+    pub name: String,
+    pub function: BuiltinFn,
+}
+
+impl BuiltinFunction {
+    fn call(&self, interpreter: &mut InterpreterState) -> bool {
+        (self.function)(interpreter)
+    }
+}
+
+impl Serialize for BuiltinFunction {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(&self.name)
+    }
+}
+
+impl<'de> Deserialize<'de> for BuiltinFunction {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let name = String::deserialize(deserializer)?;
+
+        let function = lookup_builtin(&name)
+            .ok_or_else(|| serde::de::Error::custom(format!("Unknown builtin: {}", name)))?;
+
+        Ok(BuiltinFunction { name, function })
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum FunctionItem {
+    TokenString(TokenString),
+    Builtin(BuiltinFunction),
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct InterpreterState {
+    pub stack: Vec<StackValue>,
+    pub functions: HashMap<String, FunctionItem>,
+}
+
+impl InterpreterState {
+    pub fn new() -> Self {
+        Self {
+            stack: Vec::new(),
+            functions: HashMap::new(),
+        }
+    }
+
+    pub fn init(&mut self) -> bool {
+        load_builtins(self)
+    }
+
+    pub fn push_token(&mut self, token: &Token) -> bool {
+        let value = match token {
+            Token::Eof => return true,
+
+            Token::Identifier(id) => {
+                StackValue::Identifier(id.clone())
+            }
+
+            Token::I64(v) => StackValue::I64(*v),
+            Token::I32(v) => StackValue::I32(*v),
+            Token::I16(v) => StackValue::I16(*v),
+            Token::I8(v)  => StackValue::I8(*v),
+
+            Token::U64(v) => StackValue::U64(*v),
+            Token::U32(v) => StackValue::U32(*v),
+            Token::U16(v) => StackValue::U16(*v),
+            Token::U8(v)  => StackValue::U8(*v),
+
+            Token::Float(v)  => StackValue::F32(*v),
+            Token::Double(v) => StackValue::F64(*v),
+
+            Token::Character(c) => StackValue::Character(*c),
+            Token::Boolean(b)   => StackValue::Boolean(*b),
+
+            Token::TokenString(ts) => StackValue::TokenString(ts.clone()),
+
+            Token::StringLiteral(_) |
+            Token::Array(_) |
+            Token::TypeTuple(_) => return false,
+        };
+
+        self.stack.push(value);
+        true
+    }
+
+    pub fn execute_func(&mut self, key: &str) -> bool {
+        let item = match self.functions.get(key) {
+            Some(v) => v.clone(),
+            None => return false,
+        };
+
+        match item {
+            FunctionItem::Builtin(f) => f.call(self),
+            FunctionItem::TokenString(ts) => self.execute_token_string(&ts),
+        }
+    }
+
+    pub fn execute_token_string(&mut self, ts: &TokenString) -> bool {
+        for token in &ts.tokens {
+            if let Token::Identifier(id) = &token {
+                if !id.is_literal {
+                    if !self.execute_func(&id.name) {
+                        return false;
+                    }
+                    continue;
+                }
+            }
+
+            if !self.push_token(&token) {
+                return false;
+            }
+        }
+        true
+    }
+
+    pub fn execute(&mut self, token: &Token) -> bool {
+        match token {
+            Token::Identifier(id) if !id.is_literal => {
+                self.execute_func(&id.name)
+            }
+            _ => self.push_token(token),
+        }
+    }
+
+    pub fn stack_top(&self) -> Option<&StackValue> {
+        self.stack.last()
+    }
+}

SLS_Rust/sls/src/lexer.rs

@@ -0,0 +1,742 @@
+use serde::{Serialize, Deserialize};
+
+#[derive(Debug, Clone)]
+pub struct LexerInfo {
+    pub filename: String,
+    pub source: String,
+    pub pos: usize,
+    pub column: usize,
+    pub line: usize,
+}
+
+impl LexerInfo {
+    pub fn new(filename: impl Into<String>, source: impl Into<String>) -> Self {
+        Self {
+            filename: filename.into(),
+            source: source.into(),
+            pos: 0,
+            column: 1,
+            line: 1,
+        }
+    }
+
+    fn peek(&self) -> char {
+        self.source.chars().nth(self.pos).unwrap_or('\0')
+    }
+
+    fn far_peek(&self, offset: usize) -> char {
+        self.source.chars().nth(self.pos + offset).unwrap_or('\0')
+    }
+
+    fn advance(&mut self) -> char {
+        if self.peek() == '\n' {
+            self.line += 1;
+            self.column = 1;
+        } else {
+            self.column += 1;
+        }
+        self.pos += 1;
+        self.peek()
+    }
+
+    fn skip_comments_and_whitespace(&mut self) {
+        loop {
+            let c = self.peek();
+            
+            // Skip comments
+            if (c == '/' && self.far_peek(1) == '/') || c == '#' {
+                while self.peek() != '\n' && self.peek() != '\0' {
+                    self.advance();
+                }
+            }
+            
+            // Skip whitespace
+            if self.peek().is_whitespace() {
+                while self.peek().is_whitespace() {
+                    self.advance();
+                }
+            } else {
+                break;
+            }
+        }
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Identifier {
+    pub name: String,
+    pub is_literal: bool,
+}
+
+#[derive(Debug, Clone)]
+pub enum ArrayLiteral {
+    _Identifiers(Vec<Identifier>),
+    _I64(Vec<i64>),
+    _I32(Vec<i32>),
+    _I16(Vec<i16>),
+    _I8(Vec<i8>),
+    _U64(Vec<u64>),
+    _U32(Vec<u32>),
+    _U16(Vec<u16>),
+    _U8(Vec<u8>),
+    _Float(Vec<f32>),
+    _Double(Vec<f64>),
+    _Character(Vec<u8>),
+    _Strings(Vec<String>),
+    _Boolean(Vec<bool>),
+    _TokenStrings(Vec<TokenString>),
+    _TypeTuples(Vec<TypeTuple>),
+    _StructInline(StructInline),
+}
+
+#[derive(Debug, Clone)]
+pub struct ShapedArray {
+    pub _array: ArrayLiteral,
+    pub _shape: Vec<usize>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct TokenString {
+    pub tokens: Vec<Token>,
+}
+
+#[derive(Debug, Clone)]
+pub struct TypeTuple {
+    pub _inputs: Vec<Identifier>,
+    pub _outputs: Vec<Identifier>,
+}
+
+#[derive(Debug, Clone)]
+pub struct StructInline {
+    pub _name: String,
+    pub _values: Vec<StructValue>,
+}
+
+#[derive(Debug, Clone)]
+pub enum StructValue {
+    _Integer(i64),
+    _Float(f32),
+    _Double(f64),
+    _Boolean(bool),
+    _Character(u8),
+    _String(String),
+    _Token(Token),
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum Token {
+    Eof,
+    Identifier(Identifier),
+    I64(i64),
+    I32(i32),
+    I16(i16),
+    I8(i8),
+    U64(u64),
+    U32(u32),
+    U16(u16),
+    U8(u8),
+    Float(f32),
+    Double(f64),
+    Character(u8),
+    #[serde(skip)]
+    StringLiteral(String),
+    Boolean(bool),
+    #[serde(skip)]
+    Array(ShapedArray),
+    TokenString(TokenString),
+    #[serde(skip)]
+    TypeTuple(TypeTuple),
+}
+
+#[derive(Debug, Clone)]
+pub struct LexError {
+    pub message: String,
+    pub file: String,
+    pub line: usize,
+    pub column: usize,
+}
+
+pub type LexResult<T> = Result<T, LexError>;
+
+#[derive(Debug, Clone, Copy)]
+enum NumericLiteralType {
+    Binary,
+    Octal,
+    Decimal,
+    Hexadecimal,
+    Float,
+}
+
+impl LexerInfo {
+    fn make_error(&self, message: impl Into<String>, start_line: usize, start_col: usize) -> LexError {
+        LexError {
+            message: message.into(),
+            file: self.filename.clone(),
+            line: start_line,
+            column: start_col,
+        }
+    }
+
+    fn is_identifier_continue(&self, c: char) -> bool {
+        if !c.is_ascii() || !c.is_ascii_graphic() {
+            return false;
+        }
+        if c == '/' && self.far_peek(1) == '/' {
+            return false;
+        }
+        !matches!(c, '{' | '}' | '[' | ']' | '(' | ')' | '\'' | '"' | '#') && !c.is_whitespace()
+    }
+
+    fn is_identifier_start(&self) -> bool {
+        let mut c = self.peek();
+        if c == ':' && self.far_peek(1) == ':' {
+            c = self.far_peek(2);
+        }
+        !c.is_ascii_digit() && self.is_identifier_continue(c)
+    }
+
+    fn parse_identifiers_and_booleans(&mut self, _start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+        let mut literal = false;
+
+        // Skip leading `::` for identifier literals
+        if c == ':' && self.far_peek(1) == ':' {
+            literal = true;
+            self.advance();
+            c = self.advance();
+        }
+
+        // Read the name
+        let name_start = self.pos;
+        while self.is_identifier_continue(c) {
+            if c == ':' {
+                return Err(self.make_error("Invalid identifier: ':' is not allowed in identifiers.", start_line, start_col));
+            }
+            if c == '.' {
+                return Err(self.make_error("Invalid identifier: '.' is not allowed in identifiers.", start_line, start_col));
+            }
+            c = self.advance();
+        }
+
+        let name = self.source[name_start..self.pos].to_string();
+
+        // Check for booleans
+        match name.as_str() {
+            "false" => Ok(Token::Boolean(false)),
+            "true" => Ok(Token::Boolean(true)),
+            _ => Ok(Token::Identifier(Identifier { name, is_literal: literal })),
+        }
+    }
+
+    fn parse_character_literal(&mut self, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+
+        if c == '\'' {
+            return Err(self.make_error("Invalid character literal: empty character literal.", start_line, start_col));
+        }
+
+        let value = if c == '\\' {
+            c = self.advance();
+            match c {
+                'n' => b'\n',
+                'r' => b'\r',
+                't' => b'\t',
+                '\\' => b'\\',
+                '\'' => b'\'',
+                '0' => b'\0',
+                _ => return Err(self.make_error(format!("Invalid character literal: unknown escape sequence '\\{}'.", c), start_line, start_col)),
+            }
+        } else if c == '\n' || c == '\r' {
+            return Err(self.make_error("Invalid character literal: unclosed character literal.", start_line, start_col));
+        } else {
+            c as u8
+        };
+
+        c = self.advance();
+
+        if c.is_whitespace() || c == '/' || c == '\0' {
+            return Err(self.make_error("Invalid character literal: unclosed character literal.", start_line, start_col));
+        } else if c != '\'' {
+            return Err(self.make_error(format!("Invalid character literal: unexpected '{}' in character.", c), start_line, start_col));
+        }
+
+        self.advance();
+        Ok(Token::Character(value))
+    }
+
+    fn parse_token_string(&mut self, _start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut tokens = Vec::new();
+        self.advance(); // skip '{'
+
+        loop {
+            self.skip_comments_and_whitespace();
+            let c = self.peek();
+
+            if c == '}' {
+                self.advance();
+                return Ok(Token::TokenString(TokenString { tokens }));
+            }
+
+            if c == '\0' {
+                return Err(self.make_error("Unclosed token string: missing closing brace '}'.", start_line, start_col));
+            }
+
+            match get_token(self) {
+                Some(token) => {
+                    if matches!(token, Token::Eof) {
+                        break;
+                    }
+                    tokens.push(token);
+                }
+                None => return Err(self.make_error("Failed to parse token in token string.", start_line, start_col)),
+            }
+        }
+
+        Err(self.make_error("Unclosed token string: missing closing brace '}'.", start_line, start_col))
+    }
+
+    fn parse_numeric_literal(&mut self, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+
+        if c == '-' {
+            c = self.advance();
+        }
+
+        if c == '0' {
+            c = self.advance();
+            match c {
+                'b' | 'B' => {
+                    self.advance();
+                    return self.parse_binary_integer(start, start_line, start_col);
+                }
+                'o' | 'O' => {
+                    self.advance();
+                    return self.parse_octal_integer(start, start_line, start_col);
+                }
+                'x' | 'X' => {
+                    self.advance();
+                    return self.parse_hexadecimal_integer(start, start_line, start_col);
+                }
+                _ => {}
+            }
+        }
+
+        self.parse_decimal_integer(start, start_line, start_col)
+    }
+
+    fn parse_binary_integer(&mut self, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+        while c == '0' || c == '1' || c == '_' {
+            c = self.advance();
+        }
+
+        if c == ':' {
+            return self.parse_numeric_type(start, start_line, start_col, NumericLiteralType::Binary);
+        }
+
+        let value = self.create_binary_integer(start);
+        Ok(Token::I64(value as i64))
+    }
+
+    fn parse_octal_integer(&mut self, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+        while c.is_ascii_digit() && c != '8' && c != '9' || c == '_' {
+            c = self.advance();
+        }
+
+        if c == ':' {
+            return self.parse_numeric_type(start, start_line, start_col, NumericLiteralType::Octal);
+        }
+
+        let value = self.create_octal_integer(start);
+        Ok(Token::I64(value as i64))
+    }
+
+    fn parse_decimal_integer(&mut self, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+        while c.is_ascii_digit() || c == '_' {
+            c = self.advance();
+        }
+
+        if c == '.' {
+            self.advance();
+            return self.parse_float(start, start_line, start_col);
+        }
+
+        if c == ':' {
+            return self.parse_numeric_type(start, start_line, start_col, NumericLiteralType::Decimal);
+        }
+
+        let value = self.create_decimal_integer(start);
+        Ok(Token::I64(value as i64))
+    }
+
+    fn parse_hexadecimal_integer(&mut self, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+        while c.is_ascii_hexdigit() || c == '_' {
+            c = self.advance();
+        }
+
+        if c == ':' {
+            return self.parse_numeric_type(start, start_line, start_col, NumericLiteralType::Hexadecimal);
+        }
+
+        let value = self.create_hexadecimal_integer(start);
+        Ok(Token::I64(value as i64))
+    }
+
+    fn parse_float(&mut self, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let mut c = self.peek();
+        while c.is_ascii_digit() || c == '_' {
+            c = self.advance();
+        }
+
+        if c == ':' {
+            return self.parse_numeric_type(start, start_line, start_col, NumericLiteralType::Float);
+        }
+
+        let value = self.create_float(start);
+        Ok(Token::Double(value))
+    }
+
+    fn parse_numeric_type(&mut self, start: usize, start_line: usize, start_col: usize, literal_type: NumericLiteralType) -> LexResult<Token> {
+        let mut c = self.advance(); // skip ':'
+
+        let mut is_float = false;
+        let mut is_unsigned = false;
+        let bit_size: u32;
+
+        if c == 'f' {
+            is_float = true;
+            if !matches!(literal_type, NumericLiteralType::Decimal | NumericLiteralType::Float) {
+                return Err(self.make_error("Invalid numeric literal: float type not allowed.", start_line, start_col));
+            }
+            c = self.advance();
+            if c == '6' && self.far_peek(1) == '4' {
+                bit_size = 64;
+                self.advance();
+                self.advance();
+            } else if c == '3' && self.far_peek(1) == '2' {
+                bit_size = 32;
+                self.advance();
+                self.advance();
+            } else {
+                return Err(self.make_error("Invalid float type: must be of type 'f64' or 'f32'.", start_line, start_col));
+            }
+        } else if c == 'i' || c == 'u' {
+            if matches!(literal_type, NumericLiteralType::Float) {
+                return Err(self.make_error("Invalid float type: must be of type 'f64' or 'f32'.", start_line, start_col));
+            }
+            is_unsigned = c == 'u';
+            c = self.advance();
+            if c == '6' && self.far_peek(1) == '4' {
+                bit_size = 64;
+                self.advance();
+                self.advance();
+            } else if c == '3' && self.far_peek(1) == '2' {
+                bit_size = 32;
+                self.advance();
+                self.advance();
+            } else if c == '1' && self.far_peek(1) == '6' {
+                bit_size = 16;
+                self.advance();
+                self.advance();
+            } else if c == '8' {
+                bit_size = 8;
+                self.advance();
+            } else {
+                let type_name = if is_unsigned { "unsigned" } else { "signed" };
+                return Err(self.make_error(
+                    format!("Invalid {} integer type: must be of type '{}64', '{}32', '{}16', or '{}8'.",
+                        type_name, if is_unsigned { "u" } else { "i" },
+                        if is_unsigned { "u" } else { "i" },
+                        if is_unsigned { "u" } else { "i" },
+                        if is_unsigned { "u" } else { "i" }),
+                    start_line, start_col));
+            }
+        } else {
+            return Err(self.make_error("Invalid numeric type: type must start with 'f', 'i', or 'u'.", start_line, start_col));
+        }
+
+        // Create the token based on the parsed type
+        if is_float {
+            let value = self.create_float(start);
+            match bit_size {
+                32 => Ok(Token::Float(value as f32)),
+                64 => Ok(Token::Double(value)),
+                _ => unreachable!()
+            }
+        } else {
+            let value = match literal_type {
+                NumericLiteralType::Binary => self.create_binary_integer(start),
+                NumericLiteralType::Octal => self.create_octal_integer(start),
+                NumericLiteralType::Decimal => self.create_decimal_integer(start),
+                NumericLiteralType::Hexadecimal => self.create_hexadecimal_integer(start),
+                NumericLiteralType::Float => return Err(self.make_error("Internal error: float literal in integer path", start_line, start_col)),
+            };
+
+            self.create_integer_token(value, is_unsigned, bit_size, start, start_line, start_col)
+        }
+    }
+
+    fn create_integer_token(&self, value: u64, is_unsigned: bool, bit_size: u32, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+        let is_negative = self.source[start..].starts_with('-');
+
+        match (is_unsigned, bit_size) {
+            (false, 64) => Ok(Token::I64(value as i64)),
+            (false, 32) => {
+                let signed = value as i64;
+                if signed < i32::MIN as i64 || signed > i32::MAX as i64 {
+                    return Err(self.make_error("Integer overflow: value exceeds range for i32.", start_line, start_col));
+                }
+                Ok(Token::I32(value as i32))
+            }
+            (false, 16) => {
+                let signed = value as i64;
+                if signed < i16::MIN as i64 || signed > i16::MAX as i64 {
+                    return Err(self.make_error("Integer overflow: value exceeds range for i16.", start_line, start_col));
+                }
+                Ok(Token::I16(value as i16))
+            }
+            (false, 8) => {
+                let signed = value as i64;
+                if signed < i8::MIN as i64 || signed > i8::MAX as i64 {
+                    return Err(self.make_error("Integer overflow: value exceeds range for i8.", start_line, start_col));
+                }
+                Ok(Token::I8(value as i8))
+            }
+            (true, 64) => {
+                if is_negative {
+                    return Err(self.make_error("Integer overflow: value exceeds range for u64.", start_line, start_col));
+                }
+                Ok(Token::U64(value))
+            }
+            (true, 32) => {
+                if is_negative {
+                    return Err(self.make_error("Integer overflow: value exceeds range for u32.", start_line, start_col));
+                }
+                if value > u32::MAX as u64 {
+                    return Err(self.make_error("Integer overflow: value exceeds range for u32.", start_line, start_col));
+                }
+                Ok(Token::U32(value as u32))
+            }
+            (true, 16) => {
+                if is_negative {
+                    return Err(self.make_error("Integer overflow: value exceeds range for u16.", start_line, start_col));
+                }
+                if value > u16::MAX as u64 {
+                    return Err(self.make_error("Integer overflow: value exceeds range for u16.", start_line, start_col));
+                }
+                Ok(Token::U16(value as u16))
+            }
+            (true, 8) => {
+                if is_negative {
+                    return Err(self.make_error("Integer overflow: value exceeds range for u8.", start_line, start_col));
+                }
+                if value > u8::MAX as u64 {
+                    return Err(self.make_error("Integer overflow: value exceeds range for u8.", start_line, start_col));
+                }
+                Ok(Token::U8(value as u8))
+            }
+            _ => Err(self.make_error("Invalid bit size for integer type.", start_line, start_col))
+        }
+    }
+
+    fn create_binary_integer(&self, start: usize) -> u64 {
+        let token = &self.source[start..self.pos];
+        let mut value = 0u64;
+        let mut i = 2;
+
+        if token.starts_with('-') {
+            i += 1;
+        }
+
+        for c in token[i..].chars() {
+            if c == '_' || c == '.' {
+                continue;
+            }
+            if c.is_whitespace() || c == '/' || c == ':' {
+                break;
+            }
+            value *= 2;
+            if c == '1' {
+                value += 1;
+            }
+        }
+
+        if token.starts_with('-') {
+            (!value).wrapping_add(1)
+        } else {
+            value
+        }
+    }
+
+    fn create_octal_integer(&self, start: usize) -> u64 {
+        let token = &self.source[start..self.pos];
+        let mut value = 0u64;
+        let mut i = 2;
+
+        if token.starts_with('-') {
+            i += 1;
+        }
+
+        for c in token[i..].chars() {
+            if c == '_' || c == '.' {
+                continue;
+            }
+            if c.is_whitespace() || c == '/' || c == ':' {
+                break;
+            }
+            value *= 8;
+            value += c.to_digit(8).unwrap_or(0) as u64;
+        }
+
+        if token.starts_with('-') {
+            (!value).wrapping_add(1)
+        } else {
+            value
+        }
+    }
+
+    fn create_decimal_integer(&self, start: usize) -> u64 {
+        let token = &self.source[start..self.pos];
+        let mut value = 0u64;
+        let mut i = 0;
+
+        if token.starts_with('-') {
+            i += 1;
+        }
+
+        for c in token[i..].chars() {
+            if c == '_' {
+                continue;
+            }
+            if c.is_whitespace() || c == '/' || c == ':' {
+                break;
+            }
+            value *= 10;
+            value += c.to_digit(10).unwrap_or(0) as u64;
+        }
+
+        if token.starts_with('-') {
+            (!value).wrapping_add(1)
+        } else {
+            value
+        }
+    }
+
+    fn create_hexadecimal_integer(&self, start: usize) -> u64 {
+        let token = &self.source[start..self.pos];
+        let mut value = 0u64;
+        let mut i = 2;
+
+        if token.starts_with('-') {
+            i += 1;
+        }
+
+        for c in token[i..].chars() {
+            if c == '_' || c == '.' {
+                continue;
+            }
+            if c.is_whitespace() || c == '/' || c == ':' {
+                break;
+            }
+            value *= 16;
+            value += c.to_digit(16).unwrap_or(0) as u64;
+        }
+
+        if token.starts_with('-') {
+            (!value).wrapping_add(1)
+        } else {
+            value
+        }
+    }
+
+    fn create_float(&self, start: usize) -> f64 {
+        let token = &self.source[start..self.pos];
+        let mut value = 0.0;
+        let mut fractional = 0u64;
+        let mut i = 0;
+
+        if token.starts_with('-') {
+            i += 1;
+        }
+
+        for c in token[i..].chars() {
+            if c == '_' {
+                continue;
+            }
+            if c.is_whitespace() || c == '/' || c == ':' {
+                break;
+            }
+            if c == '.' {
+                fractional = 1;
+                continue;
+            }
+
+            if fractional == 0 {
+                value *= 10.0;
+            } else {
+                fractional *= 10;
+            }
+
+            let digit = c.to_digit(10).unwrap_or(0) as f64;
+            if fractional == 0 {
+                value += digit;
+            } else {
+                value += digit / fractional as f64;
+            }
+        }
+
+        if token.starts_with('-') {
+            -value
+        } else {
+            value
+        }
+    }
+}
+
+pub fn get_token(lexer: &mut LexerInfo) -> Option<Token> {
+    lexer.skip_comments_and_whitespace();
+
+    let c = lexer.peek();
+    let start = lexer.pos;
+    let start_line = lexer.line;
+    let start_col = lexer.column;
+
+    if c == '\0' {
+        return Some(Token::Eof);
+    }
+
+    let result = if c.is_ascii_digit() || (c == '.' && lexer.far_peek(1).is_ascii_digit()) || (c == '-' && lexer.far_peek(1).is_ascii_digit()) {
+        lexer.parse_numeric_literal(start, start_line, start_col)
+    } else if c == '\'' {
+        lexer.advance();
+        lexer.parse_character_literal(start_line, start_col)
+    } else if c == '{' {
+        lexer.parse_token_string(start, start_line, start_col)
+    } else if lexer.is_identifier_start() {
+        lexer.parse_identifiers_and_booleans(start, start_line, start_col)
+    } else {
+        Err(lexer.make_error(format!("Unexpected character: '{}'", c), start_line, start_col))
+    };
+
+    result.ok()
+}
+
+pub fn lexical_analysis(lexer: &mut LexerInfo) -> LexResult<Vec<Token>> {
+    let mut tokens = Vec::new();
+
+    loop {
+        match get_token(lexer) {
+            Some(Token::Eof) => {
+                tokens.push(Token::Eof);
+                break;
+            }
+            Some(token) => tokens.push(token),
+            None => break,
+        }
+    }
+
+    Ok(tokens)
+}

SLS_Rust/sls/src/main.rs

@@ -0,0 +1,63 @@
+mod builtin;
+mod file;
+mod interpreter;
+mod lexer;
+mod repl;
+
+use std::env;
+use std::process;
+
+use file::run_file;
+use repl::repl;
+
+// These mirror the C macros.
+const SLS_NAME: &str = "SLS_RUST";
+const SLS_VER: &str = "0.0.2-alpha";
+
+pub fn print_version() {
+    let git_hash = option_env!("GIT_COMMIT_HASH").unwrap_or("unknown");
+    let compiler = option_env!("COMPILER_NAME").unwrap_or("rustc");
+    let compiler_ver = option_env!("COMPILER_VER").unwrap_or("unknown");
+    let build_date = std::env::var("BUILD_DATE").unwrap_or_else(|_| "unknown".into());
+    let build_time = std::env::var("BUILD_TIME").unwrap_or_else(|_| "unknown".into());
+
+    println!("YREA SLS ({SLS_NAME}) {SLS_VER} ({git_hash})");
+    println!("Compiled with {compiler} {compiler_ver} at {build_date} {build_time}");
+}
+
+fn main() {
+    let mut args = env::args().skip(1);
+
+    let mut version_flag = false;
+    let mut filename: Option<String> = None;
+
+    match args.len() {
+        0 => {}
+        1 => {
+            let arg = args.next().unwrap();
+            if arg == "--version" || arg == "-v" {
+                version_flag = true;
+            } else {
+                filename = Some(arg);
+            }
+        }
+        _ => {
+            eprintln!("Too many arguments!");
+            process::exit(1);
+        }
+    }
+
+    if version_flag {
+        print_version();
+        process::exit(0);
+    }
+
+    if let Some(file) = filename {
+        let status = run_file(&file);
+        process::exit(status);
+    }
+
+    // Default to REPL
+    let status = repl();
+    process::exit(status);
+}

SLS_Rust/sls/src/repl.rs

@@ -0,0 +1,116 @@
+use std::io::{self, Write};
+use std::fs;
+use serde_json;
+
+use crate::lexer::{LexerInfo, LexResult, lexical_analysis};
+use crate::print_version;
+use crate::interpreter::{InterpreterState, StackValue};
+
+static REPL_FILE_NAME: &str = "<STDIN>";
+
+fn print_top_of_stack(state: &InterpreterState) {
+    let Some(item) = state.stack_top() else {
+        println!("#0: <STACK IS EMPTY>");
+        return;
+    };
+
+    match &item {
+        StackValue::Identifier(id) => {
+            println!("#0: ::{}", id.name);
+        }
+        StackValue::I64(v) => println!("#0: {}", v),
+        StackValue::I32(v) => println!("#0: {}:i32", v),
+        StackValue::I16(v) => println!("#0: {}:i16", v),
+        StackValue::I8(v)  => println!("#0: {}:i8", v),
+
+        StackValue::U64(v) => println!("#0: {}:u64", v),
+        StackValue::U32(v) => println!("#0: {}:u32", v),
+        StackValue::U16(v) => println!("#0: {}:u16", v),
+        StackValue::U8(v)  => println!("#0: {}:u8", v),
+
+        StackValue::F32(v) => println!("#0: {}:f32", v),
+        StackValue::F64(v) => println!("#0: {}", v),
+
+        StackValue::Character(ch) => println!("#0: {}", ch),
+        StackValue::Boolean(b) => println!("#0: {}", if *b { "TRUE" } else { "FALSE" }),
+
+        StackValue::TokenString(_) => println!("#0: <TOKEN STRING>"),
+        StackValue::Callable(_)    => println!("#0: <CALLABLE>"),
+    };
+}
+
+pub fn repl() -> i32 {
+    print_version();
+    println!("===== YREA SLS REPL =====");
+    println!("Type `#exit` to exit.");
+    io::stdout().flush().unwrap();
+
+    let mut interpreter = InterpreterState::new();
+    if !interpreter.init() {
+        return 1;
+    }
+
+    let stdin = io::stdin();
+    let mut buf = String::new();
+
+    loop {
+        buf.clear();
+
+        if stdin.read_line(&mut buf).is_err() {
+            return 1;
+        }
+
+        if buf.trim_end() == "#exit" {
+            return 0;
+        }
+
+        if let Some(file) = buf.trim_end().strip_prefix("#save ") {
+            match serde_json::to_string(&interpreter) {
+                Ok(json) => {
+                    if let Err(err) = fs::write(file, json) {
+                        eprintln!("Failed to save state: {}", err);
+                    } else {
+                        println!("State saved to {}", file);
+                    }
+                }
+                Err(err) => eprintln!("Serialization error: {}", err),
+            }
+            continue;
+        }
+
+        if let Some(file) = buf.trim_end().strip_prefix("#load ") {
+            match fs::read_to_string(file) {
+                Ok(json) => match serde_json::from_str(&json) {
+                    Ok(state) => {
+                        interpreter = state;
+                        println!("State restored from {}", file);
+                    }
+                    Err(err) => eprintln!("Deserialization error: {}", err),
+                },
+                Err(err) => eprintln!("Failed to read file: {}", err),
+            }
+            continue;
+        }
+
+        let code = buf.clone();
+        let mut lexer_info = LexerInfo::new(REPL_FILE_NAME, code.clone());
+        let result = lexical_analysis(&mut lexer_info);
+
+        match result {
+            LexResult::Ok(tokens) => {
+                for token in tokens {
+                    if !interpreter.execute(&token) {
+                        eprintln!("A runtime error occured!");
+                        break;
+                    }
+                }
+
+                print_top_of_stack(&interpreter);
+            }
+
+            LexResult::Err(err) => {
+                dbg!(err);
+            }
+        }
+    }
+}

SLS_Tests/generate_tests/__init__.py

@@ -5,6 +5,7 @@ from .float_tests import FloatTestGenerator
 from .char_tests import CharTestGenerator
 from .string_tests import StringTestGenerator
 from .idents_and_bools_tests import IdentifierTestGenerator, BooleanTestGenerator
+from .token_strings import TokenStringTestGenerator
 
 __all__ = [
     "BaseTestGenerator",
@@ -15,4 +16,5 @@ __all__ = [
     "StringTestGenerator",
     "IdentifierTestGenerator",
     "BooleanTestGenerator",
+    "TokenStringTestGenerator",
 ]

SLS_Tests/generate_tests/base_tests.py

@@ -54,6 +54,8 @@ class BaseTestGenerator(ABC):
 
     ENABLE_UNICODE = False
     ENABLE_EXPONENTIAL_LITERALS = False
+    ENABLE_CHAR_HEX_ESCAPE = False
+    ENABLE_STRINGS = False
 
     __generators: "ClassVar[List[Type[BaseTestGenerator]]]" = []
 
@@ -365,3 +367,39 @@ class BaseTestGenerator(ABC):
         if not self.validate_test_names_unique():
             duplicates = self.get_duplicate_test_names()
             print(f"  WARNING: Duplicate test names found: {duplicates}")
+
+    # =========================================================================
+    # Token String Helpers
+    # =========================================================================
+
+    def make_token_string_token(self, inner_tokens: List[Token]) -> Token:
+        """
+        Create a token string token containing inner tokens.
+
+        Args:
+            inner_tokens: List of tokens inside the token string
+
+        Returns:
+            Token with type "token_string" and tokens array
+        """
+        return Token(type="token_string", value=[t.__dict__ for t in inner_tokens])
+
+    def make_token_string_test(self, name: str, code: str, inner_tokens: List[Token]):
+        """
+        Create a successful token string test.
+
+        Args:
+            name: Test name
+            code: Source code
+            inner_tokens: Tokens inside the token string
+        """
+        token = self.make_token_string_token(inner_tokens)
+
+        # For operations, we push the token string as a value
+        op_value = {"tokens": [t.__dict__ for t in inner_tokens]}
+        op = self.make_push_op("token_string", op_value)
+
+        # On the stack, it's a token_string value
+        stack = self.make_stack_item("token_string", op_value)
+
+        self.add_test(name, code, [token], [op], [stack])

SLS_Tests/generate_tests/char_tests.py

@@ -28,10 +28,10 @@ class CharTestGenerator(BaseTestGenerator):
     def generate_basic_tests(self):
         """Generate basic character literal tests."""
         # Simple ASCII letters
-        self.make_success_test("Char Simple Letter A", "'A'", "char", 'A')
-        self.make_success_test("Char Simple Letter a", "'a'", "char", 'a')
-        self.make_success_test("Char Simple Letter Z", "'Z'", "char", 'Z')
-        self.make_success_test("Char Simple Letter z", "'z'", "char", 'z')
+        self.make_success_test("Char Simple Letter Uppercase A", "'A'", "char", 'A')
+        self.make_success_test("Char Simple Letter Lowercase a", "'a'", "char", 'a')
+        self.make_success_test("Char Simple Letter Uppercase Z", "'Z'", "char", 'Z')
+        self.make_success_test("Char Simple Letter Lowercase z", "'z'", "char", 'z')
         
         # Digits
         self.make_success_test("Char Digit 0", "'0'", "char", '0')
@@ -74,6 +74,7 @@ class CharTestGenerator(BaseTestGenerator):
     
     def generate_hexadecimal_escape_tests(self):
         """Generate tests for hexadecimal escape sequences."""
+        if self.ENABLE_CHAR_HEX_ESCAPE:
             # Additional specific hex escapes
             self.make_success_test("Char Hex Lowercase A", "'\\\\x61'", "char", 'a')
             self.make_success_test("Char Hex Uppercase A", "'\\\\x41'", "char", 'A')
@@ -165,6 +166,7 @@ class CharTestGenerator(BaseTestGenerator):
                            "Invalid character literal: unknown escape sequence '\\\\q'.")
         
         # Invalid hex escape (not 2 digits)
+        if self.ENABLE_CHAR_HEX_ESCAPE:
             self.make_error_test("Char Hex Escape Too Short",
                             "'\\\\x4'",
                             "Invalid character literal: hexadecimal escape must have exactly 2 digits.")
@@ -215,6 +217,7 @@ class CharTestGenerator(BaseTestGenerator):
     
     def generate_edge_case_tests(self):
         """Generate edge case tests."""
+        if self.ENABLE_CHAR_HEX_ESCAPE:
             # ASCII control characters
             self.make_success_test("Char ASCII Control SOH", "'\\\\x01'", "char", '\x01')
             self.make_success_test("Char ASCII Control BEL", "'\\\\x07'", "char", '\x07')
@@ -245,6 +248,7 @@ class CharTestGenerator(BaseTestGenerator):
     
     def generate_case_sensitivity_tests(self):
         """Generate tests for case sensitivity in escape sequences."""
+        if self.ENABLE_CHAR_HEX_ESCAPE:
             # Hex escapes - lowercase x
             self.make_success_test("Char Hex Lowercase x", "'\\\\x41'", "char", 'A')
             

SLS_Tests/generate_tests/float_tests.py

@@ -221,7 +221,7 @@ class FloatTestGenerator(BaseTestGenerator):
         # Comma separators not allowed
         self.make_error_test("Float Invalid Comma Separator",
                            "1,234.56",
-                           "Invalid float literal: unexpected ',' in float.")
+                           "Invalid decimal literal: unexpected ',' in decimal integer.")
 
     def generate_whitespace_tests(self):
         """Generate tests with whitespace."""

SLS_Tests/generate_tests/idents_and_bools_tests.py

@@ -7,7 +7,7 @@ class IdentifierTestGenerator(BaseTestGenerator):
     
     # Reserved words that might be operators or keywords
     RESERVED_WORDS = [
-        'true', 'false', 'if', 'while', 'for', 'match', 'break', 'continue',
+        'if', 'while', 'for', 'match', 'break', 'continue',
         'fn', 'struct', 'union', 'enum', 'trait', 'impl', 'inher',
         'dup', 'drop', 'swap', 'over', 'rot', 'pick', 'roll', 'depth',
     ]
@@ -66,7 +66,7 @@ class IdentifierTestGenerator(BaseTestGenerator):
         
         # Others
         self.make_success_test("Identifier With Dash", "my-var",
-                              "identifier_literal", "my-var")
+                              "identifier", "my-var")
     
     def generate_identifier_literal_tests(self):
         """Generate identifier literal tests (with :: prefix)."""
@@ -153,17 +153,12 @@ class IdentifierTestGenerator(BaseTestGenerator):
                            "Invalid decimal literal: unexpected 'a' in decimal integer.")
         
         # Invalid characters
-        self.make_error_test("Identifier With Hash",
-                           "my#var",
-                           "Invalid identifier: '#' is not allowed in identifiers.")
+        self.make_success_test("Identifier With Octothorpe", "my#var",
+                           "identifier", "my")
         
-        self.make_error_test("Identifier With Dot",
-                           "my.var",
-                           "Invalid identifier: '.' is not allowed in identifiers.")
-        
-        self.make_error_test("Identifier With Space",
-                           "my var",
-                           "Invalid identifier: whitespace not allowed in identifiers.")
+        # self.make_error_test("Identifier With Space",
+        #                    "my var",
+        #                    "Invalid identifier: whitespace not allowed in identifiers.")
         
         self.make_error_test("Identifier With Colon",
                            "my:var",
@@ -172,47 +167,45 @@ class IdentifierTestGenerator(BaseTestGenerator):
         # Note: :: is allowed only as prefix for identifier literals
         self.make_error_test("Identifier Double Colon Inside",
                            "my::var",
-                           "Invalid identifier: '::' only allowed as prefix for identifier literals.")
+                           "Invalid identifier: ':' is not allowed in identifiers.")
         
         # Special characters
-        self.make_error_test("Identifier With At",
-                           "@variable",
-                           "Invalid identifier: '@' is not allowed in identifiers.")
+        # self.make_error_test("Identifier With At",
+        #                    "@variable",
+        #                    "Invalid identifier: '@' is not allowed in identifiers.")
         
-        self.make_error_test("Identifier With Dollar",
-                           "$variable",
-                           "Invalid identifier: '$' is not allowed in identifiers.")
+        # self.make_error_test("Identifier With Dollar",
+        #                    "$variable",
+        #                    "Invalid identifier: '$' is not allowed in identifiers.")
         
-        self.make_error_test("Identifier With Percent",
-                           "%variable",
-                           "Invalid identifier: '%' is not allowed in identifiers.")
+        # self.make_error_test("Identifier With Percent",
+        #                    "%variable",
+        #                    "Invalid identifier: '%' is not allowed in identifiers.")
         
         # Brackets not allowed
-        self.make_error_test("Identifier With Brackets",
-                           "my[var]",
-                           "Invalid identifier: brackets not allowed in identifiers.")
+        # self.make_error_test("Identifier With Brackets",
+        #                    "my[var]",
+        #                    "Invalid identifier: brackets not allowed in identifiers.")
         
-        self.make_error_test("Identifier With Braces",
-                           "my{var}",
-                           "Invalid identifier: braces not allowed in identifiers.")
+        # self.make_error_test("Identifier With Braces",
+        #                    "my{var}",
+        #                    "Invalid identifier: braces not allowed in identifiers.")
         
-        self.make_error_test("Identifier With Parens",
-                           "my(var)",
-                           "Invalid identifier: parentheses not allowed in identifiers.")
+        # self.make_error_test("Identifier With Parens",
+        #                    "my(var)",
+        #                    "Invalid identifier: parentheses not allowed in identifiers.")
         
         # Quotes not allowed
-        self.make_error_test("Identifier With Single Quote",
-                           "my'var",
-                           "Invalid identifier: quotes not allowed in identifiers.")
+        # self.make_error_test("Identifier With Single Quote",
+        #                    "my'var",
+        #                    "Invalid identifier: quotes not allowed in identifiers.")
         
-        self.make_error_test("Identifier With Double Quote",
-                           'my"var',
-                           "Invalid identifier: quotes not allowed in identifiers.")
+        # self.make_error_test("Identifier With Double Quote",
+        #                    'my"var',
+        #                    "Invalid identifier: quotes not allowed in identifiers.")
         
         # Only numbers (not valid identifier)
-        self.make_error_test("Identifier Only Numbers",
-                           "123",
-                           "Not an identifier: numeric literal.")
+        self.make_success_test("Identifier Only Numbers", "123", "i64", 123)
         
         # Empty identifier literal
         self.make_error_test("Identifier Literal Empty",
@@ -329,6 +322,7 @@ class BooleanTestGenerator(BaseTestGenerator):
         self.make_success_test("Bool Numeric 0", "0", "i64", 0)
         
         # String representations
+        if self.ENABLE_STRINGS:
             self.make_success_test("Bool String True", '"true"',
                             "string", "true")
             

SLS_Tests/generate_tests/integer_tests.py

@@ -141,47 +141,39 @@ class IntegerTestGenerator(BaseTestGenerator):
                            f"{underflow_val}:{type_name}",
                            f"Integer overflow: value exceeds range for {type_name}.")
 
-    def generate_special_typed_tests(self, type_name: str):
-        """Generate special tests for specific types."""
-        min_val, max_val = self.TYPE_RANGES[type_name]
-        is_unsigned = type_name.startswith('u')
-
         # Underscores with type annotation
-        if max_val >= 1000000:
+        if max_range >= 1000000:
             self.make_success_test(f"Integer {type_name} With Underscores",
                                   f"1_000_000:{type_name}", type_name, 1000000)
 
+    def generate_special_typed_tests(self):
+        """Generate special tests for specific types."""
+
         # Special values for specific types
-        if type_name == 'i8':
         self.make_success_test("Integer i8 Hex Max", "0x7F:i8", "i8", 127)
         self.make_success_test("Integer i8 Binary Max", "0b01111111:i8", "i8", 127)
         self.make_success_test("Integer i8 Octal Max", "0o177:i8", "i8", 127)
         self.make_success_test("Integer i8 Negative Hex", "-0x80:i8", "i8", -128)
 
-        elif type_name == 'u8':
         self.make_success_test("Integer u8 Hex Max", "0xFF:u8", "u8", 255)
         self.make_success_test("Integer u8 Binary Max", "0b11111111:u8", "u8", 255)
         self.make_success_test("Integer u8 Octal Max", "0o377:u8", "u8", 255)
 
-        elif type_name == 'i16':
         self.make_success_test("Integer i16 Hex Sample", "0x1234:i16", "i16", 4660)
         self.make_success_test("Integer i16 Binary Sample",
-                                  "0b1111111100000000:i16", "i16", 65280)
+                                "0b1111111100000000:i16", "i16", -256)
         self.make_success_test("Integer i16 Octal Sample", "0o1234:i16", "i16", 668)
 
-        elif type_name == 'u16':
         self.make_success_test("Integer u16 Hex Max", "0xFFFF:u16", "u16", 65535)
         self.make_success_test("Integer u16 Binary Max",
                                 "0b1111111111111111:u16", "u16", 65535)
         self.make_success_test("Integer u16 Octal Max", "0o177777:u16", "u16", 65535)
         self.make_success_test("Integer u16 Decimal Mid", "50000:u16", "u16", 50000)
 
-        elif type_name == 'i32':
         self.make_success_test("Integer i32 Hex Sample", "0xABCD:i32", "i32", 43981)
         self.make_success_test("Integer i32 Binary Sample",
                                 "0b11110000:i32", "i32", 240)
 
-        elif type_name == 'u32':
         self.make_success_test("Integer u32 Hex Max", "0xFFFFFFFF:u32", "u32", 4294967295)
         self.make_success_test("Integer u32 Binary Sample",
                                 "0b11111111000000001111111100000000:u32",
@@ -190,13 +182,11 @@ class IntegerTestGenerator(BaseTestGenerator):
                                 "0o37777777777:u32", "u32", 4294967295)
         self.make_success_test("Integer u32 Decimal Mid", "1000000:u32", "u32", 1000000)
 
-        elif type_name == 'i64':
         self.make_success_test("Integer i64 Decimal Positive 42", "42:i64", "i64", 42)
         self.make_success_test("Integer i64 Hex 0xFF", "0xFF:i64", "i64", 255)
         self.make_success_test("Integer i64 Binary 0b1010", "0b1010:i64", "i64", 10)
         self.make_success_test("Integer i64 Octal 0o755", "0o755:i64", "i64", 493)
 
-        elif type_name == 'u64':
         self.make_success_test("Integer u64 Hex Max",
                                 "0xFFFFFFFFFFFFFFFF:u64",
                                 "u64", "UINT64_MAX")
@@ -227,7 +217,7 @@ class IntegerTestGenerator(BaseTestGenerator):
         # Tests for each specific type
         for type_name in ['i8', 'i16', 'i32', 'i64', 'u8', 'u16', 'u32', 'u64']:
             self.generate_typed_tests(type_name)
-            self.generate_special_typed_tests(type_name)
+        self.generate_special_typed_tests()
 
         # Additional edge cases
         self.generate_underscore_tests()

SLS_Tests/generate_tests/string_tests.py

@@ -436,6 +436,10 @@ class StringTestGenerator(BaseTestGenerator):
     
     def generate_all_tests(self) -> List[Dict[str, Any]]:
         """Generate all string literal test cases."""
+        
+        if not self.ENABLE_STRINGS:
+            return []
+        
         # Basic tests
         self.generate_basic_tests()
         

SLS_Tests/generate_tests/token_strings.py

@@ -0,0 +1,623 @@
+from typing import List, Dict, Any
+from .base_tests import BaseTestGenerator, Token
+
+
+class TokenStringTestGenerator(BaseTestGenerator):
+    """Generate test cases for token strings (unparsed code blocks in braces)."""
+    
+    def generate_basic_tests(self):
+        """Generate basic token string tests."""
+        # Empty token string
+        self.make_token_string_test(
+            "TokenString Empty",
+            "{ }",
+            []
+        )
+        
+        # Single token
+        self.make_token_string_test(
+            "TokenString Single Integer",
+            "{ 42 }",
+            [Token(type="i64", value=42)]
+        )
+        
+        self.make_token_string_test(
+            "TokenString Single Identifier",
+            "{ dup }",
+            [Token(type="identifier", value="dup")]
+        )
+        
+        # Two tokens
+        self.make_token_string_test(
+            "TokenString Two Integers",
+            "{ 2 3 }",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3)
+            ]
+        )
+        
+        # Simple expression
+        self.make_token_string_test(
+            "TokenString Simple Expression",
+            "{ 2 3 + }",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Stack manipulation
+        self.make_token_string_test(
+            "TokenString Stack Ops",
+            "{ dup * }",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="identifier", value="*")
+            ]
+        )
+    
+    def generate_literal_tests(self):
+        """Generate tests with various literal types inside token strings."""
+        # Integer literals
+        self.make_token_string_test(
+            "TokenString Integer Literals",
+            "{ 0 42 -10 1000 }",
+            [
+                Token(type="i64", value=0),
+                Token(type="i64", value=42),
+                Token(type="i64", value=-10),
+                Token(type="i64", value=1000)
+            ]
+        )
+        
+        # Float literals
+        self.make_token_string_test(
+            "TokenString Float Literals",
+            "{ 3.14 -2.5 0.0 }",
+            [
+                Token(type="f64", value=3.14),
+                Token(type="f64", value=-2.5),
+                Token(type="f64", value=0.0)
+            ]
+        )
+        
+        # String literals
+        if self.ENABLE_STRINGS:
+            self.make_token_string_test(
+                "TokenString String Literal",
+                '{ "hello" }',
+                [Token(type="String", value="hello")]
+            )
+            
+            self.make_token_string_test(
+                "TokenString Multiple Strings",
+                '{ "hello" "world" }',
+                [
+                    Token(type="String", value="hello"),
+                    Token(type="String", value="world")
+                ]
+            )
+        
+        # Character literals
+        self.make_token_string_test(
+            "TokenString Char Literal",
+            "{ 'A' }",
+            [Token(type="char", value='A')]
+        )
+        
+        # Boolean literals
+        self.make_token_string_test(
+            "TokenString Boolean Literals",
+            "{ true false }",
+            [
+                Token(type="bool", value=True),
+                Token(type="bool", value=False)
+            ]
+        )
+        
+        # Mixed literals
+        if self.ENABLE_STRINGS:
+            self.make_token_string_test(
+                "TokenString Mixed Literals",
+                '{ 42 3.14 "hello" true \'A\' }',
+                [
+                    Token(type="i64", value=42),
+                    Token(type="f64", value=3.14),
+                    Token(type="String", value="hello"),
+                    Token(type="bool", value=True),
+                    Token(type="char", value='A')
+                ]
+            )
+    
+    def generate_identifier_tests(self):
+        """Generate tests with various identifiers inside token strings."""
+        # Multiple identifiers
+        self.make_token_string_test(
+            "TokenString Multiple Identifiers",
+            "{ dup swap over }",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="identifier", value="swap"),
+                Token(type="identifier", value="over")
+            ]
+        )
+        
+        # Identifier literals (with ::)
+        self.make_token_string_test(
+            "TokenString Identifier Literals",
+            "{ ::x ::y }",
+            [
+                Token(type="identifier_literal", value="x"),
+                Token(type="identifier_literal", value="y")
+            ]
+        )
+        
+        # Mixed identifiers and literals
+        self.make_token_string_test(
+            "TokenString Mixed Identifiers",
+            "{ ::Point get x swap }",
+            [
+                Token(type="identifier_literal", value="Point"),
+                Token(type="identifier", value="get"),
+                Token(type="identifier", value="x"),
+                Token(type="identifier", value="swap")
+            ]
+        )
+    
+    def generate_nested_tests(self):
+        """Generate tests with nested token strings."""
+        # Single nesting
+        inner_tokens = [
+            Token(type="i64", value=2),
+            Token(type="i64", value=3),
+            Token(type="identifier", value="+")
+        ]
+        inner_token_string = self.make_token_string_token(inner_tokens)
+        
+        self.make_token_string_test(
+            "TokenString Nested Single",
+            "{ { 2 3 + } }",
+            [inner_token_string]
+        )
+        
+        # Nested with other tokens
+        self.make_token_string_test(
+            "TokenString Nested With Others",
+            "{ x { dup * } }",
+            [
+                Token(type="identifier", value="x"),
+                self.make_token_string_token([
+                    Token(type="identifier", value="dup"),
+                    Token(type="identifier", value="*")
+                ])
+            ]
+        )
+        
+        # Multiple nested
+        self.make_token_string_test(
+            "TokenString Multiple Nested",
+            "{ { 2 3 + } { 4 5 * } }",
+            [
+                self.make_token_string_token([
+                    Token(type="i64", value=2),
+                    Token(type="i64", value=3),
+                    Token(type="identifier", value="+")
+                ]),
+                self.make_token_string_token([
+                    Token(type="i64", value=4),
+                    Token(type="i64", value=5),
+                    Token(type="identifier", value="*")
+                ])
+            ]
+        )
+        
+        # Double nesting
+        deepest = self.make_token_string_token([Token(type="i64", value=42)])
+        middle = self.make_token_string_token([deepest])
+        
+        self.make_token_string_test(
+            "TokenString Double Nested",
+            "{ { { 42 } } }",
+            [middle]
+        )
+        
+        # Complex nesting with mixed content
+        self.make_token_string_test(
+            "TokenString Complex Nesting",
+            "{ 1 { 2 { 3 } 4 } 5 }",
+            [
+                Token(type="i64", value=1),
+                self.make_token_string_token([
+                    Token(type="i64", value=2),
+                    self.make_token_string_token([
+                        Token(type="i64", value=3)
+                    ]),
+                    Token(type="i64", value=4)
+                ]),
+                Token(type="i64", value=5)
+            ]
+        )
+    
+    def generate_whitespace_tests(self):
+        """Generate tests with various whitespace patterns."""
+        # No whitespace inside
+        self.make_token_string_test(
+            "TokenString No Whitespace",
+            "{2 3 +}",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Extra whitespace
+        self.make_token_string_test(
+            "TokenString Extra Whitespace",
+            "{   2    3     +   }",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Leading whitespace outside
+        self.make_token_string_test(
+            "TokenString Leading Whitespace Outside",
+            "   { 2 3 + }",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Trailing whitespace outside
+        self.make_token_string_test(
+            "TokenString Trailing Whitespace Outside",
+            "{ 2 3 + }   ",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Tabs
+        self.make_token_string_test(
+            "TokenString With Tabs",
+            "{\\t2\\t3\\t+\\t}",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+    
+    def generate_multiline_tests(self):
+        """Generate tests with multiline token strings."""
+        # Simple multiline
+        self.make_token_string_test(
+            "TokenString Multiline Simple",
+            "{\\n    2 3 +\\n}",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Multiple lines with tokens
+        self.make_token_string_test(
+            "TokenString Multiline Multiple",
+            "{\\n    dup\\n    *\\n    2\\n    +\\n}",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="identifier", value="*"),
+                Token(type="i64", value=2),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Mixed line breaks
+        self.make_token_string_test(
+            "TokenString Mixed Line Breaks",
+            "{ 1 2\\n3 4\\n\\n5 6 }",
+            [
+                Token(type="i64", value=1),
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="i64", value=4),
+                Token(type="i64", value=5),
+                Token(type="i64", value=6)
+            ]
+        )
+        
+        # Indented multiline
+        self.make_token_string_test(
+            "TokenString Indented Multiline",
+            "{\\n    dup 0 >\\n        { }\\n        { 0 swap - }\\n    if\\n}",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="i64", value=0),
+                Token(type="identifier", value=">"),
+                self.make_token_string_token([]),
+                self.make_token_string_token([
+                    Token(type="i64", value=0),
+                    Token(type="identifier", value="swap"),
+                    Token(type="identifier", value="-")
+                ]),
+                Token(type="identifier", value="if")
+            ]
+        )
+    
+    def generate_comment_tests(self):
+        """Generate tests with comments inside token strings."""
+        # Comment at end of line inside token string
+        self.make_token_string_test(
+            "TokenString Comment End Of Line",
+            "{ 2 3 + // add them\\n}",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Multiple comments
+        self.make_token_string_test(
+            "TokenString Multiple Comments",
+            "{ 2 // first\\n3 // second\\n+ // add\\n}",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Comment on its own line
+        self.make_token_string_test(
+            "TokenString Comment Own Line",
+            "{\\n    // This is a comment\\n    2 3 +\\n}",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Comment at start
+        self.make_token_string_test(
+            "TokenString Comment At Start",
+            "{ // comment\\n2 3 + }",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Multiple comment lines
+        self.make_token_string_test(
+            "TokenString Multiple Comment Lines",
+            "{\\n    // First comment\\n    // Second comment\\n    2 3 +\\n}",
+            [
+                Token(type="i64", value=2),
+                Token(type="i64", value=3),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Comments in nested token strings
+        self.make_token_string_test(
+            "TokenString Comments Nested",
+            "{ { 2 3 + // inner comment\\n} // outer comment\\n}",
+            [
+                self.make_token_string_token([
+                    Token(type="i64", value=2),
+                    Token(type="i64", value=3),
+                    Token(type="identifier", value="+")
+                ])
+            ]
+        )
+    
+    def generate_error_tests(self):
+        """Generate error test cases."""
+        # Unclosed token string
+        self.make_error_test(
+            "TokenString Unclosed",
+            "{ 2 3 +",
+            "Unclosed token string: missing closing brace '}'."
+        )
+        
+        # Unclosed nested
+        self.make_error_test(
+            "TokenString Unclosed Nested",
+            "{ { 2 3 + }",
+            "Unclosed token string: missing closing brace '}'."
+        )
+        
+        # Extra closing brace (generates two tokens: valid token string + error)
+        token = self.make_token_string_token([
+            Token(type="i64", value=2),
+            Token(type="i64", value=3),
+            Token(type="identifier", value="+")
+        ])
+        error_token = self.make_error_token(
+            "Unexpected closing brace '}' without matching opening brace."
+        )
+        self.add_test(
+            "TokenString Extra Closing Brace",
+            "{ 2 3 + } }",
+            [token, error_token]
+        )
+        
+        # Only closing brace
+        self.make_error_test(
+            "TokenString Only Closing Brace",
+            "}",
+            "Unexpected closing brace '}' without matching opening brace."
+        )
+        
+        # Error inside token string (invalid literal)
+        error_inside = self.make_token_string_token([
+            Token(type="i64", value=2),
+            Token(type="error", value="Invalid decimal literal: unexpected 'a' in decimal integer."),
+            Token(type="identifier", value="+")
+        ])
+        op_value = {"tokens": [
+            {"type": "i64", "value": 2},
+            {"type": "error", "value": "Invalid decimal literal: unexpected 'a' in decimal integer."},
+            {"type": "identifier", "value": "+"}
+        ]}
+        op = self.make_push_op("token_string", op_value)
+        stack = self.make_stack_item("token_string", op_value)
+        
+        self.add_test(
+            "TokenString Error Inside",
+            "{ 2 3a + }",
+            [error_inside],
+            [op],
+            [stack]
+        )
+        
+        # Unclosed string inside token string
+        error_string = self.make_token_string_token([
+            Token(type="error", value="Invalid string literal: unclosed string literal.")
+        ])
+        op_value_str = {"tokens": [
+            {"type": "error", "value": "Invalid string literal: unclosed string literal."}
+        ]}
+        op_str = self.make_push_op("token_string", op_value_str)
+        stack_str = self.make_stack_item("token_string", op_value_str)
+        
+        if self.ENABLE_STRINGS:
+            self.add_test(
+                "TokenString Unclosed String Inside",
+                '{ "hello }',
+                [error_string],
+                [op_str],
+                [stack_str]
+            )
+    
+    def generate_complex_tests(self):
+        """Generate complex realistic test cases."""
+        # Function body
+        self.make_token_string_test(
+            "TokenString Function Body",
+            "{ dup * }",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="identifier", value="*")
+            ]
+        )
+        
+        # If statement branches
+        if self.ENABLE_STRINGS:
+            self.make_token_string_test(
+                "TokenString If Branches",
+                '{ "positive" print }',
+                [
+                    Token(type="String", value="positive"),
+                    Token(type="identifier", value="print")
+                ]
+            )
+        
+        # Loop body
+        self.make_token_string_test(
+            "TokenString Loop Body",
+            "{ dup print 1 + }",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="identifier", value="print"),
+                Token(type="i64", value=1),
+                Token(type="identifier", value="+")
+            ]
+        )
+        
+        # Struct definition
+        self.make_token_string_test(
+            "TokenString Struct Fields",
+            "{ x: y: }",
+            [
+                Token(type="identifier", value="x"),
+                Token(type="identifier", value=":"),
+                Token(type="identifier", value="y"),
+                Token(type="identifier", value=":")
+            ]
+        )
+        
+        # Lambda expression
+        self.make_token_string_test(
+            "TokenString Lambda",
+            "{ 2 * }",
+            [
+                Token(type="i64", value=2),
+                Token(type="identifier", value="*")
+            ]
+        )
+        
+        # Array map operation
+        self.make_token_string_test(
+            "TokenString Array Map",
+            "{ dup * }",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="identifier", value="*")
+            ]
+        )
+        
+        # Conditional with nested token strings
+        self.make_token_string_test(
+            "TokenString Conditional Complex",
+            "{\\n    dup 0 >\\n        { dup * }\\n        { drop 0 }\\n    if\\n}",
+            [
+                Token(type="identifier", value="dup"),
+                Token(type="i64", value=0),
+                Token(type="identifier", value=">"),
+                self.make_token_string_token([
+                    Token(type="identifier", value="dup"),
+                    Token(type="identifier", value="*")
+                ]),
+                self.make_token_string_token([
+                    Token(type="identifier", value="drop"),
+                    Token(type="i64", value=0)
+                ]),
+                Token(type="identifier", value="if")
+            ]
+        )
+    
+    def generate_all_tests(self) -> List[Dict[str, Any]]:
+        """Generate all token string test cases."""
+        # Basic tests
+        self.generate_basic_tests()
+        
+        # Literal types
+        self.generate_literal_tests()
+        
+        # Identifiers
+        self.generate_identifier_tests()
+        
+        # Nested token strings
+        self.generate_nested_tests()
+        
+        # Whitespace handling
+        self.generate_whitespace_tests()
+        
+        # Multiline token strings
+        self.generate_multiline_tests()
+        
+        # Comments inside token strings
+        self.generate_comment_tests()
+        
+        # Error cases
+        self.generate_error_tests()
+        
+        # Complex realistic cases
+        self.generate_complex_tests()
+        
+        return self.get_tests()
+

SLS_Tests/interpreter_tester/README.md

@@ -0,0 +1,124 @@
+# Interpreter Test Runner
+
+Requires `pip install pyyaml`
+
+Test SLS (UNIX):  
+`python3 test_runner.py ../../SLS_C/bin/sls tests.yaml`  
+`python3 test_runner.py "python3 -m ../../SLS_Python/sls" tests.yaml`  
+`python3 test_runner.py ../../SLS_Rust/target/debug/sls tests.yaml`  
+
+Test SLS (Windows):  
+`python test_runner.py ..\..\SLS_C\bin\sls.exe tests.yaml`  
+`python test_runner.py "python -m ..\..\SLS_Python\sls" tests.yaml`  
+`python test_runner.py ..\..\SLS_Rust\target\debug\sls.exe tests.yaml`  
+
+Python Examples:  
+`python test_runner.py python python_tests.yaml`  
+`python test_runner.py pypy python_tests.yaml`  
+
+```
+>python test_runner.py python python_tests.yaml
+✓ PASS: Simple print statement
+
+✓ PASS: Basic arithmetic
+
+✓ PASS: Variable assignment and usage
+
+✗ FAIL: Syntax error detection
+  Reason: stderr mismatch
+Expected:
+SyntaxError: unterminated string literal (detected at line 1)
+
+Got:
+  File "<stdin>", line 1
+    print("missing closing quote)
+          ^
+SyntaxError: unterminated string literal (detected at line 1)
+
+
+✓ PASS: Import and use module
+
+✓ PASS: List operations
+
+✓ PASS: Execute Python file with args
+
+✓ PASS: Division by zero error
+
+✗ FAIL: Check Python version (using args instead of stdin)
+  Reason: stdout mismatch
+Expected:
+Python 3
+Got:
+Python 3.14.0
+
+
+✓ PASS: Multi-line function definition
+
+✓ PASS: Long running operation with custom timeout
+
+============================================================
+TEST SUMMARY
+============================================================
+Total tests: 11
+Passed: 9
+Failed: 2
+
+Failed tests:
+  - Syntax error detection
+  - Check Python version (using args instead of stdin)
+============================================================
+```
+
+```
+>python test_runner.py pypy python_tests.yaml
+✓ PASS: Simple print statement
+
+✓ PASS: Basic arithmetic
+
+✓ PASS: Variable assignment and usage
+
+✗ FAIL: Syntax error detection
+  Reason: stderr mismatch
+Expected:
+SyntaxError: unterminated string literal (detected at line 1)
+
+Got:
+  File "<stdin>", line 1
+    print("missing closing quote)
+          ^^^^^^^^^^^^^^^^^^^^^^^
+SyntaxError: unterminated string literal (detected at line 1)
+
+
+✓ PASS: Import and use module
+
+✓ PASS: List operations
+
+✓ PASS: Execute Python file with args
+
+✓ PASS: Division by zero error
+
+✗ FAIL: Check Python version (using args instead of stdin)
+  Reason: stdout mismatch
+Expected:
+Python 3
+Got:
+Python 3.10.13 (f1607341da97ff5a1e93430b6e8c4af0ad1aa019, Sep 28 2023, 05:42:24)
+[PyPy 7.3.13 with MSC v.1929 64 bit (AMD64)]
+
+
+✓ PASS: Multi-line function definition
+
+✓ PASS: Long running operation with custom timeout
+
+============================================================
+TEST SUMMARY
+============================================================
+Total tests: 11
+Passed: 9
+Failed: 2
+
+Failed tests:
+  - Syntax error detection
+  - Check Python version (using args instead of stdin)
+============================================================
+```

SLS_Tests/interpreter_tester/python_tests.yaml

@@ -0,0 +1,95 @@
+tests:
+  - name: "Simple print statement"
+    stdin: |
+      print("Hello, World!")
+    stdout: |
+      Hello, World!
+    exit: success
+
+  - name: "Basic arithmetic"
+    stdin: |
+      print(2 + 2)
+      print(10 * 5)
+    stdout: |
+      4
+      50
+    exit: success
+
+  - name: "Variable assignment and usage"
+    stdin: |
+      x = 42
+      y = 8
+      print(x + y)
+    stdout: |
+      50
+    exit: success
+
+  - name: "Syntax error detection"
+    stdin: |
+      print("missing closing quote)
+    stderr: |
+      SyntaxError: unterminated string literal (detected at line 1)
+    exit: error
+    error_code: 1
+
+  - name: "Import and use module"
+    stdin: |
+      import math
+      print(math.pi)
+    stdout: |
+      3.141592653589793
+    exit: success
+
+  - name: "List operations"
+    stdin: |
+      numbers = [1, 2, 3, 4, 5]
+      print(sum(numbers))
+      print(len(numbers))
+    stdout: |
+      15
+      5
+    exit: success
+
+  - name: "Execute Python file with args"
+    args: ["-c", "import sys; print(f'Args: {sys.argv[1:]}'); print('Done')", "arg1", "arg2"]
+    stdout: |
+      Args: ['arg1', 'arg2']
+      Done
+    exit: success
+
+  - name: "Division by zero error"
+    stdin: |
+      print(1 / 0)
+    stderr: |
+      Traceback (most recent call last):
+        File "<stdin>", line 1, in <module>
+      ZeroDivisionError: division by zero
+    exit: error
+
+  - name: "Check Python version (using args instead of stdin)"
+    args: ["--version"]
+    stdout: "Python 3"
+    exit: success
+    timeout: 2.0
+
+  - name: "Multi-line function definition"
+    stdin: |
+      def greet(name):
+          return f"Hello, {name}!"
+      
+      print(greet("Alice"))
+      print(greet("Bob"))
+    stdout: |
+      Hello, Alice!
+      Hello, Bob!
+    exit: success
+
+  - name: "Long running operation with custom timeout"
+    stdin: |
+      import time
+      time.sleep(0.5)
+      print("Done sleeping")
+    stdout: |
+      Done sleeping
+    exit: success
+    timeout: 2.0

SLS_Tests/interpreter_tester/test_runner.py

@@ -0,0 +1,212 @@
+#!/usr/bin/env python3
+"""
+CLI Testing Script - Test executables with stdin/stdout/stderr validation
+"""
+
+import argparse
+import subprocess
+import sys
+import yaml
+from pathlib import Path
+from typing import Optional, Dict, Any, List
+from dataclasses import dataclass
+from enum import Enum
+
+
+class ExitBehavior(Enum):
+    NONE = "none"
+    SUCCESS = "success"
+    ERROR = "error"
+
+
+@dataclass
+class TestResult:
+    name: str
+    passed: bool
+    reason: Optional[str] = None
+
+
+class TestRunner:
+    def __init__(self, executable: str, default_timeout: float = 5.0):
+        self.executable = executable
+        self.default_timeout = default_timeout
+        self.results: List[TestResult] = []
+
+    def run_command(self, stdin: Optional[str], args: List[str], timeout: float) -> tuple:
+        """Run the executable and capture output"""
+        try:
+            cmd = [self.executable] + args
+            result = subprocess.run(
+                cmd,
+                input=stdin,
+                capture_output=True,
+                text=True,
+                timeout=timeout
+            )
+            return result.stdout, result.stderr, result.returncode, None
+        except subprocess.TimeoutExpired:
+            return None, None, None, "Timeout"
+        except Exception as e:
+            return None, None, None, f"Error: {str(e)}"
+
+    def normalize_output(self, text: Optional[str]) -> str:
+        """Normalize output by stripping trailing whitespace from each line"""
+        if text is None:
+            return ""
+        lines = text.split('\n')
+        return '\n'.join(line.rstrip() for line in lines)
+
+    def check_exit_behavior(self, returncode: int, expected: Dict[str, Any]) -> tuple[bool, Optional[str]]:
+        """Check if exit behavior matches expectation"""
+        behavior = expected.get("exit", "none")
+        
+        if behavior == "none":
+            return True, None
+        elif behavior == "success":
+            if returncode == 0:
+                return True, None
+            return False, f"Expected success (exit 0), got exit code {returncode}"
+        elif behavior == "error":
+            expected_code = expected.get("error_code")
+            if expected_code is not None:
+                if returncode == expected_code:
+                    return True, None
+                return False, f"Expected error code {expected_code}, got {returncode}"
+            else:
+                if returncode != 0:
+                    return True, None
+                return False, f"Expected error (non-zero exit), got exit code 0"
+        
+        return False, f"Unknown exit behavior: {behavior}"
+
+    def run_test(self, test: Dict[str, Any]) -> TestResult:
+        """Run a single test case"""
+        name = test.get("name", "Unnamed test")
+        timeout = test.get("timeout", self.default_timeout)
+        
+        # Setup phase
+        setup_stdin = test.get("setup")
+        if setup_stdin:
+            setup_args = test.get("setup_args", [])
+            _, _, _, error = self.run_command(setup_stdin, setup_args, timeout)
+            if error:
+                return TestResult(name, False, f"Setup failed: {error}")
+        
+        # Main test execution
+        stdin = test.get("stdin")
+        args = test.get("args", [])
+        stdout, stderr, returncode, error = self.run_command(stdin, args, timeout)
+        
+        if error:
+            # Cleanup even on error
+            self.run_cleanup(test, timeout)
+            return TestResult(name, False, error)
+        
+        # Check stdout
+        expected_stdout = test.get("stdout")
+        if expected_stdout is not None:
+            actual = self.normalize_output(stdout)
+            expected = self.normalize_output(expected_stdout)
+            if actual != expected:
+                self.run_cleanup(test, timeout)
+                return TestResult(name, False, f"stdout mismatch\nExpected:\n{expected}\nGot:\n{actual}")
+        
+        # Check stderr
+        expected_stderr = test.get("stderr")
+        if expected_stderr is not None:
+            actual = self.normalize_output(stderr)
+            expected = self.normalize_output(expected_stderr)
+            if actual != expected:
+                self.run_cleanup(test, timeout)
+                return TestResult(name, False, f"stderr mismatch\nExpected:\n{expected}\nGot:\n{actual}")
+        
+        # Check exit behavior
+        passed, reason = self.check_exit_behavior(returncode, test)
+        if not passed:
+            self.run_cleanup(test, timeout)
+            return TestResult(name, False, reason)
+        
+        # Cleanup phase
+        cleanup_result = self.run_cleanup(test, timeout)
+        if cleanup_result:
+            return TestResult(name, False, f"Cleanup failed: {cleanup_result}")
+        
+        return TestResult(name, True)
+
+    def run_cleanup(self, test: Dict[str, Any], timeout: float) -> Optional[str]:
+        """Run cleanup if specified"""
+        cleanup_stdin = test.get("cleanup")
+        if cleanup_stdin:
+            cleanup_args = test.get("cleanup_args", [])
+            _, _, _, error = self.run_command(cleanup_stdin, cleanup_args, timeout)
+            return error
+        return None
+
+    def run_all_tests(self, tests: List[Dict[str, Any]]):
+        """Run all tests and collect results"""
+        for test in tests:
+            result = self.run_test(test)
+            self.results.append(result)
+            
+            # Print immediate result
+            status = "✓ PASS" if result.passed else "✗ FAIL"
+            print(f"{status}: {result.name}")
+            if not result.passed and result.reason:
+                print(f"  Reason: {result.reason}")
+            print()
+
+    def print_summary(self):
+        """Print test summary"""
+        total = len(self.results)
+        passed = sum(1 for r in self.results if r.passed)
+        failed = total - passed
+        
+        print("=" * 60)
+        print("TEST SUMMARY")
+        print("=" * 60)
+        print(f"Total tests: {total}")
+        print(f"Passed: {passed}")
+        print(f"Failed: {failed}")
+        
+        if failed > 0:
+            print("\nFailed tests:")
+            for result in self.results:
+                if not result.passed:
+                    print(f"  - {result.name}")
+        
+        print("=" * 60)
+        
+        return 0 if failed == 0 else 1
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Test CLI executables with YAML test definitions")
+    parser.add_argument("executable", help="Path to the executable to test")
+    parser.add_argument("tests", help="Path to YAML test file")
+    parser.add_argument("--timeout", type=float, default=5.0, help="Default timeout in seconds (default: 5.0)")
+    
+    args = parser.parse_args()
+    
+    # Load test file
+    try:
+        with open(args.tests, 'r') as f:
+            test_data = yaml.safe_load(f)
+    except Exception as e:
+        print(f"Error loading test file: {e}", file=sys.stderr)
+        return 1
+    
+    tests = test_data.get("tests", [])
+    if not tests:
+        print("No tests found in test file", file=sys.stderr)
+        return 1
+    
+    # Run tests
+    runner = TestRunner(args.executable, args.timeout)
+    runner.run_all_tests(tests)
+    
+    # Print summary and return exit code
+    return runner.print_summary()
+
+
+if __name__ == "__main__":
+    sys.exit(main())

SLS_Tests/interpreter_tester/tests.yaml

@@ -0,0 +1,706 @@
+tests:
+  # Basic Stack Operations
+  - name: "Simple value push"
+    stdin: |
+      42 print
+    stdout: |
+      42
+    exit: success
+
+  - name: "Multiple values and operations"
+    stdin: |
+      3 4 + print
+      10 5 - print
+    stdout: |
+      7
+      5
+    exit: success
+
+  - name: "Stack manipulation - dup"
+    stdin: |
+      5 dup print print
+    stdout: |
+      5
+      5
+    exit: success
+
+  - name: "Stack manipulation - swap"
+    stdin: |
+      10 20 swap print print
+    stdout: |
+      10
+      20
+    exit: success
+
+  - name: "Stack manipulation - over"
+    stdin: |
+      5 10 over print print print
+    stdout: |
+      5
+      10
+      5
+    exit: success
+
+  - name: "Stack manipulation - rot"
+    stdin: |
+      1 2 3 rot print print print
+    stdout: |
+      1
+      2
+      3
+    exit: success
+
+  - name: "Stack depth"
+    stdin: |
+      1 2 3 depth print
+    stdout: |
+      3
+    exit: success
+
+  # Arithmetic Operations
+  - name: "Basic arithmetic - all operators"
+    stdin: |
+      10 3 + print
+      10 3 - print
+      10 3 * print
+      10 3 / print
+      10 3 % print
+    stdout: |
+      13
+      7
+      30
+      3
+      1
+    exit: success
+
+  - name: "Exponentiation"
+    stdin: |
+      2 8 ^ print
+      3 3 ^ print
+    stdout: |
+      256
+      27
+    exit: success
+
+  - name: "Floating point arithmetic"
+    stdin: |
+      3.14 2.0 + print
+      10.5 2.5 * print
+    stdout: |
+      5.14
+      26.25
+    exit: success
+
+  - name: "Mathematical functions"
+    stdin: |
+      16 sqrt print
+      -42 abs print
+      3.7 round print
+      3.14 floor print
+      3.14 ceil print
+    stdout: |
+      4.0
+      42
+      4.0
+      3.0
+      4.0
+    exit: success
+
+  - name: "Min and max"
+    stdin: |
+      3 5 min print
+      3 5 max print
+    stdout: |
+      3
+      5
+    exit: success
+
+  # Comparison Operations
+  - name: "Comparison operators"
+    stdin: |
+      5 3 > print
+      5 3 < print
+      5 5 == print
+      5 3 != print
+      5 5 >= print
+      3 5 <= print
+    stdout: |
+      true
+      false
+      true
+      true
+      true
+      true
+    exit: success
+
+  # Logical Operations
+  - name: "Logical operators"
+    stdin: |
+      true false and print
+      true false or print
+      false not print
+    stdout: |
+      false
+      true
+      true
+    exit: success
+
+  # Bitwise Operations
+  - name: "Bitwise operations"
+    stdin: |
+      0xFF 0x0F bitand print
+      0xF0 0x0F bitor print
+      0xFF 0x0F bitxor print
+      4 2 shl print
+      16 2 shr print
+    stdout: |
+      15
+      255
+      240
+      16
+      4
+    exit: success
+
+  # String Operations
+  - name: "String concatenation"
+    stdin: |
+      "hello" " world" concat print
+    stdout: |
+      hello world
+    exit: success
+
+  - name: "String length and substring"
+    stdin: |
+      "hello" length print
+      "hello" 1 3 substr print
+    stdout: |
+      5
+      el
+    exit: success
+
+  - name: "String split and join"
+    stdin: |
+      "a,b,c" "," split print
+    stdout: |
+      ["a" "b" "c"]
+    exit: success
+
+  - name: "String searching"
+    stdin: |
+      "hello" "hel" starts_with print
+      "hello" "lo" ends_with print
+    stdout: |
+      true
+      true
+    exit: success
+
+  - name: "String trimming and replacement"
+    stdin: |
+      "  hello  " trim print
+      "hello world" "world" "Stack" replace print
+    stdout: |
+      hello
+      hello Stack
+    exit: success
+
+  # Array Operations
+  - name: "Array literals and access"
+    stdin: |
+      [1 2 3 4 5] print
+      [1 2 3 4 5] 2 at print
+      [1 2 3 4 5] length print
+    stdout: |
+      [1 2 3 4 5]
+      3
+      5
+    exit: success
+
+  - name: "Array slice"
+    stdin: |
+      [10 20 30 40 50] 1 3 slice print
+    stdout: |
+      [20 30]
+    exit: success
+
+  - name: "Array map"
+    stdin: |
+      [1 2 3 4] { 2 * } map print
+    stdout: |
+      [2 4 6 8]
+    exit: success
+
+  - name: "Array filter"
+    stdin: |
+      [1 2 3 4 5] { 2 % 0 == } filter print
+    stdout: |
+      [2 4]
+    exit: success
+
+  - name: "Array reduce"
+    stdin: |
+      [1 2 3 4] 0 { + } reduce print
+    stdout: |
+      10
+    exit: success
+
+  - name: "Array sum and mean"
+    stdin: |
+      [1 2 3 4 5] sum print
+      [1 2 3 4 5] mean print
+    stdout: |
+      15
+      3.0
+    exit: success
+
+  - name: "Array zip and enumerate"
+    stdin: |
+      [1 2 3] [4 5 6] zip print
+      ["a" "b" "c"] enumerate print
+    stdout: |
+      [[1 4] [2 5] [3 6]]
+      [[0 "a"] [1 "b"] [2 "c"]]
+    exit: success
+
+  - name: "Array reverse and transpose"
+    stdin: |
+      [1 2 3] reverse print
+      [[1 2] [3 4]] transpose print
+    stdout: |
+      [3 2 1]
+      [[1 3] [2 4]]
+    exit: success
+
+  # Function Definition and Calling
+  - name: "Simple function definition"
+    stdin: |
+      (Number -- Number) { dup * } ::square fn
+      5 square print
+    stdout: |
+      25
+    exit: success
+
+  - name: "Function with multiple operations"
+    stdin: |
+      (Number Number -- Number Number) {
+        over over / swap %
+      } ::divmod fn
+      10 3 divmod print print
+    stdout: |
+      3
+      1
+    exit: success
+
+  - name: "Recursive factorial"
+    stdin: |
+      (Number -- Number) {
+        dup 1 <=
+          { drop 1 }
+          { dup 1 - factorial * }
+        if
+      } ::factorial fn
+      5 factorial print
+    stdout: |
+      120
+    exit: success
+
+  # Control Flow - Conditionals
+  - name: "Simple if statement"
+    stdin: |
+      5 0 > { "positive" print } { "negative" print } if
+    stdout: |
+      positive
+    exit: success
+
+  - name: "If with else branch"
+    stdin: |
+      -3 0 > { "positive" print } { "non-positive" print } if
+    stdout: |
+      non-positive
+    exit: success
+
+  - name: "Nested conditionals"
+    stdin: |
+      5 0 >
+        {
+          5 10 
+            { "between 0 and 10" print }
+            { "greater than 10" print }
+          if
+        }
+        { "negative or zero" print }
+      if
+    stdout: |
+      between 0 and 10
+    exit: success
+
+  # Control Flow - Loops
+  - name: "For loop"
+    stdin: |
+      1 5 { dup print } for
+    stdout: |
+      1
+      2
+      3
+      4
+      5
+    exit: success
+
+  - name: "While loop"
+    stdin: |
+      0
+      { dup 3 < }
+      {
+        dup print
+        1 +
+      }
+      while
+      drop
+    stdout: |
+      0
+      1
+      2
+    exit: success
+
+  - name: "Loop with break"
+    stdin: |
+      1 10 {
+        dup 5 ==
+          { break }
+          { dup print }
+        if
+      } for
+    stdout: |
+      1
+      2
+      3
+      4
+    exit: success
+
+  - name: "Loop with continue"
+    stdin: |
+      1 5 {
+        dup 2 % 0 ==
+          { continue }
+          { dup print }
+        if
+      } for
+    stdout: |
+      1
+      3
+      5
+    exit: success
+
+  # Structs
+  - name: "Struct definition and creation"
+    stdin: |
+      (Number Number --) { x: y: } ::Point struct
+      3.0 4.0 Point print
+    stdout: |
+      Point { x: 3.0, y: 4.0 }
+    exit: success
+
+  - name: "Struct field access"
+    stdin: |
+      (Number Number --) { x: y: } ::Point struct
+      3.0 4.0 Point
+      dup ::x get print
+      ::y get print
+    stdout: |
+      3.0
+      4.0
+    exit: success
+
+  - name: "Struct field modification"
+    stdin: |
+      (Number Number --) { x: y: } ::Point struct
+      3.0 4.0 Point
+      10.0 ::x set
+      ::x get print
+    stdout: |
+      10.0
+    exit: success
+
+  # Unions
+  - name: "Union creation - Option type"
+    stdin: |
+      (T --) { Some(T) None } ::Option union
+      42 Option::Some print
+      Option::None print
+    stdout: |
+      Option::Some(42)
+      Option::None
+    exit: success
+
+  - name: "Pattern matching with Option"
+    stdin: |
+      (T --) { Some(T) None } ::Option union
+      42 Option::Some {
+        Some(x) => { x print }
+        None => { "Nothing" print }
+      } match
+    stdout: |
+      42
+    exit: success
+
+  - name: "Result type pattern matching"
+    stdin: |
+      (T E --) { Ok(T) Err(E) } ::Result union
+      "success" Result::Ok {
+        Ok(val) => { val print }
+        Err(e) => { "Error: " e concat print }
+      } match
+    stdout: |
+      success
+    exit: success
+
+  # Enums
+  - name: "Enum definition and usage"
+    stdin: |
+      { Pending: Active: Complete: } ::Status enum
+      Status::Active print
+    stdout: |
+      Status::Active
+    exit: success
+
+  # Traits
+  - name: "Trait implementation for struct"
+    stdin: |
+      (Number Number --) { x: y: } ::Point struct
+      ::Addable {
+        (Self Self -- Self) {
+          over ::x get over ::x get +
+          swap ::y get swap ::y get +
+          Point
+        } +:
+      } ::Point impl
+      1.0 2.0 Point 3.0 4.0 Point + print
+    stdout: |
+      Point { x: 4.0, y: 6.0 }
+    exit: success
+
+  # Type Conversions
+  - name: "Type conversions"
+    stdin: |
+      42 to_f64 print
+      3.14 to_i32 print
+      42 to_str print
+    stdout: |
+      42.0
+      3
+      "42"
+    exit: success
+
+  - name: "String parsing"
+    stdin: |
+      "123" parse print
+    stdout: |
+      123
+    exit: success
+
+  # Constants
+  - name: "Constant definition and usage"
+    stdin: |
+      3.1415926535 ::pi const
+      5 dup * pi * print
+    stdout: |
+      78.53981633975
+    exit: success
+
+  # Lambda and Eval
+  - name: "Lambda function"
+    stdin: |
+      { dup * } lambda ::square swap
+      5 square eval print
+    stdout: |
+      25
+    exit: success
+
+  - name: "Eval operator"
+    stdin: |
+      "2 3 +" eval print
+    stdout: |
+      5
+    exit: success
+
+  # Reflection
+  - name: "Type checking with type_of"
+    stdin: |
+      42 type_of print
+      "hello" type_of print
+    stdout: |
+      ::i64
+      ::String
+    exit: success
+
+  - name: "Trait checking with implements"
+    stdin: |
+      42 ::Addable implements print
+      42 ::Drawable implements print
+    stdout: |
+      true
+      false
+    exit: success
+
+  # Assertions
+  - name: "Passing assertion"
+    stdin: |
+      { 2 3 + } { 5 == } assert
+      "Test passed" print
+    stdout: |
+      Test passed
+    exit: success
+
+  - name: "Failing assertion"
+    stdin: |
+      { 2 3 + } { 6 == } assert
+    stderr: |
+      Assertion failed
+    exit: error
+
+  # Randomness
+  - name: "Random number generation with seed"
+    stdin: |
+      12345 seed
+      rand 0.0 >= print
+      rand 1.0 < print
+    stdout: |
+      true
+      true
+    exit: success
+
+  # Complex Examples
+  - name: "FizzBuzz (1-15)"
+    stdin: |
+      (Number -- ) {
+        dup 15 % 0 ==
+          { drop "FizzBuzz" print }
+          {
+            dup 3 % 0 ==
+              { drop "Fizz" print }
+              {
+                dup 5 % 0 ==
+                  { drop "Buzz" print }
+                  { print }
+                if
+              }
+            if
+          }
+        if
+      } ::fizzbuzz fn
+      1 15 { fizzbuzz } for
+    stdout: |
+      1
+      2
+      Fizz
+      4
+      Buzz
+      Fizz
+      7
+      8
+      Fizz
+      Buzz
+      11
+      Fizz
+      13
+      14
+      FizzBuzz
+    exit: success
+
+  - name: "Sum of squares of even numbers"
+    stdin: |
+      [1 2 3 4 5 6 7 8 9 10]
+        { 2 % 0 == } filter
+        { dup * } map
+        0 { + } reduce
+      print
+    stdout: |
+      220
+    exit: success
+
+  # Error Cases
+  - name: "Type mismatch error"
+    stdin: |
+      "hello" 5 +
+    stderr: |
+      Type error
+    exit: error
+
+  - name: "Stack underflow"
+    stdin: |
+      +
+    stderr: |
+      Stack underflow
+    exit: error
+
+  - name: "Undefined identifier"
+    stdin: |
+      undefined_function
+    stderr: |
+      Undefined identifier: undefined_function
+    exit: error
+
+  - name: "Division by zero"
+    stdin: |
+      10 0 /
+    stderr: |
+      Division by zero
+    exit: error
+
+  # Character Literals
+  - name: "Character literals"
+    stdin: |
+      'A' print
+      '\n' print
+      '\u{1F600}' print
+    stdout: |
+      'A'
+      '\n'
+      '😀'
+    exit: success
+
+  # Multiple test with timeout
+  - name: "Complex computation with timeout"
+    stdin: |
+      1 100 { dup * } map 0 { + } reduce print
+    stdout: |
+      338350
+    exit: success
+    timeout: 2.0
+
+  # Comments
+  - name: "Comments ignored"
+    stdin: |
+      // This is a comment
+      5 // inline comment
+      3 + // another comment
+      print
+    stdout: |
+      8
+    exit: success
+
+  # Array of structs
+  - name: "Array of structs"
+    stdin: |
+      (Number Number --) { x: y: } ::Point struct
+      [1 2 Point 3 4 Point] print
+    stdout: |
+      [Point { x: 1, y: 2 }, Point { x: 3, y: 4 }]
+    exit: success
+
+  # Format strings
+  - name: "String formatting"
+    stdin: |
+      "x=%d, y=%d" [5 10] format print
+    stdout: |
+      x=5, y=10
+    exit: success
+
+  # Underscore separators in literals
+  - name: "Underscore separators in numbers"
+    stdin: |
+      1_000_000 print
+      3_1415.92_65 print
+    stdout: |
+      1000000
+      3141.9265
+    exit: success

SLS_Tests/yaml_to_c_tests.py

@@ -83,10 +83,150 @@ def _token_to_c_call(token: dict, idx_var="i") -> str:
     elif ttype == "bool":
         return f'test_boolean_value(&test, result, {idx_var}++, &(Boolean){{{"TRUE" if value else "FALSE"}}})' # type: ignore
     elif ttype == "error":
-        return f'test_for_error(&test, result, i++, SLS_STR("{c_string_literal(value)}"))' # type: ignore
+        return f'test_for_error(&test, result, i++, &SLS_STR("{c_string_literal(value)}"))' # type: ignore
+    elif ttype == "token_string":
+        return _token_string_c_call(idx_var, value) # type: ignore
     else:
         raise ValueError(f' Unhandled token type: {ttype}')
 
+def _token_string_c_call(idx_var: str, value: list[dict]) -> str:
+    """Generate C code for testing a token string value."""
+    if not value:  # Empty token string
+        return (
+            f'test_token_string_value(&test, result, {idx_var}++, '
+            f'&(TestTokenStringValue){{0, NULL}})'
+        )
+
+    # Generate token handler calls for each token in the string
+    token_handlers = []
+    for i, inner_token in enumerate(value):
+        inner_type = inner_token.get("type")
+        inner_value = inner_token.get("value")
+
+        # Determine the handler function and value initialization
+        if inner_type == "i64":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_I64, {inner_value}}}'
+        elif inner_type == "i32":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_I32, {inner_value}}}'
+        elif inner_type == "i16":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_I16, {inner_value}}}'
+        elif inner_type == "i8":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_I8, {inner_value}}}'
+        elif inner_type == "u64":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_U64, {inner_value}}}'
+        elif inner_type == "u32":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_U32, {inner_value}}}'
+        elif inner_type == "u16":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_U16, {inner_value}}}'
+        elif inner_type == "u8":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_U8, {inner_value}}}'
+        elif inner_type == "f64":
+            handler = "test_double_value"
+            val_init = f'&(double){{{inner_value}}}'
+        elif inner_type == "f32":
+            handler = "test_float_value"
+            val_init = f'&(float){{{inner_value}}}'
+        elif inner_type == "char":
+            handler = "test_character_value"
+            val_init = f'&(uint8_t){{{ord(inner_value)}}}' # type: ignore
+        elif inner_type == "string":
+            handler = "test_string_value"
+            val_init = f'&SLS_STR("{c_string_literal(inner_value)}")' # type: ignore
+        elif inner_type == "identifier":
+            handler = "test_identifier_value"
+            val_init = f'&(TestIdentifierValue){{FALSE, SLS_STR("{inner_value}")}}'
+        elif inner_type == "identifier_literal":
+            handler = "test_identifier_value"
+            val_init = f'&(TestIdentifierValue){{TRUE, SLS_STR("{inner_value}")}}'
+        elif inner_type == "bool":
+            handler = "test_boolean_value"
+            val_init = f'&(Boolean){{{"TRUE" if inner_value else "FALSE"}}}'
+        elif inner_type == "error":
+            handler = "test_for_error"
+            val_init = f'&SLS_STR("{c_string_literal(inner_value)}")' # type: ignore
+        elif inner_type == "token_string":
+            # Nested token string - recursive call
+            handler = "test_token_string_value"
+            val_init = _token_string_value_init(inner_token.get("value", []))
+        else:
+            raise ValueError(f'Unhandled token type in token string: {inner_type}')
+
+        token_handlers.append(
+            f'{{(Boolean (*)(LexerTest *, LexerResult, size_t, void *)){handler}, '
+            f'{val_init}}}'
+        )
+
+    # Generate the array initialization
+    tokens_array = f'(TestTokenStringToken[]){{{", ".join(token_handlers)}}}'
+
+    return (
+        f'test_token_string_value(&test, result, {idx_var}++, '
+        f'&(TestTokenStringValue){{{len(value)}, {tokens_array}}})'
+    )
+
+def _token_string_value_init(value: list[dict]) -> str:
+    """Generate initialization code for a TestTokenStringValue (for nested token strings)."""
+    if not value:
+        return '&(TestTokenStringValue){0, NULL}'
+
+    token_handlers = []
+    for inner_token in value:
+        inner_type = inner_token.get("type")
+        inner_value = inner_token.get("value")
+
+        if inner_type == "i64":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_I64, {inner_value}}}'
+        elif inner_type == "i32":
+            handler = "test_integer_value"
+            val_init = f'&(TestIntegerValue){{INTEGER_I32, {inner_value}}}'
+        elif inner_type == "f64":
+            handler = "test_double_value"
+            val_init = f'&(double){{{inner_value}}}'
+        elif inner_type == "f32":
+            handler = "test_float_value"
+            val_init = f'&(float){{{inner_value}}}'
+        elif inner_type == "char":
+            handler = "test_character_value"
+            val_init = f'&(uint8_t){{{ord(inner_value)}}}' # type: ignore
+        elif inner_type == "string":
+            handler = "test_string_value"
+            val_init = f'&SLS_STR("{c_string_literal(inner_value)}")' # type: ignore
+        elif inner_type == "identifier":
+            handler = "test_identifier_value"
+            val_init = f'&(TestIdentifierValue){{FALSE, SLS_STR("{inner_value}")}}'
+        elif inner_type == "identifier_literal":
+            handler = "test_identifier_value"
+            val_init = f'&(TestIdentifierValue){{TRUE, SLS_STR("{inner_value}")}}'
+        elif inner_type == "bool":
+            handler = "test_boolean_value"
+            val_init = f'&(Boolean){{{"TRUE" if inner_value else "FALSE"}}}'
+        elif inner_type == "error":
+            handler = "test_for_error"
+            val_init = f'&SLS_STR("{c_string_literal(inner_value)}")' # type: ignore
+        elif inner_type == "token_string":
+            handler = "test_token_string_value"
+            val_init = _token_string_value_init(inner_token.get("value", []))
+        # Add other types as needed
+        else:
+            raise ValueError(f'Unhandled token type in nested token string: {inner_type}')
+
+        token_handlers.append(
+            f'{{(Boolean (*)(LexerTest *, LexerResult, size_t, void *)){handler}, '
+            f'{val_init}}}'
+        )
+
+    tokens_array = f'(TestTokenStringToken[]){{{", ".join(token_handlers)}}}'
+    return f'&(TestTokenStringValue){{{len(value)}, {tokens_array}}}'
+
 def token_to_c_call(token: dict, idx_var="i") -> str:
     """Generate a C 'test_*_value' call based on token type."""
     return f"if ({_token_to_c_call(token, idx_var)}) return test.result;"