diff --git a/SLS_Rust/sls/src/builtin.rs b/SLS_Rust/sls/src/builtin.rs
index e69de29..5a2fed6 100644
--- a/SLS_Rust/sls/src/builtin.rs
+++ b/SLS_Rust/sls/src/builtin.rs
@@ -0,0 +1,5 @@
+use crate::interpreter::InterpreterState;
+
+pub fn load_builtins(_state: &mut InterpreterState) -> bool {
+    false
+}
diff --git a/SLS_Rust/sls/src/file.rs b/SLS_Rust/sls/src/file.rs
index 0d306eb..4b016fd 100644
--- a/SLS_Rust/sls/src/file.rs
+++ b/SLS_Rust/sls/src/file.rs
@@ -14,7 +14,7 @@ pub fn exec_file(interpreter: &mut InterpreterState, filename: &str) -> bool {
         }
     };
 
-    let mut lexer_info = LexerInfo::new(filename.clone(), source.clone());
+    let mut lexer_info = LexerInfo::new(filename, source.clone());
 
     let result = lexical_analysis(&mut lexer_info);
 
@@ -40,6 +40,9 @@ 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
diff --git a/SLS_Rust/sls/src/interpreter.rs b/SLS_Rust/sls/src/interpreter.rs
index bdafc86..ae4ee2d 100644
--- a/SLS_Rust/sls/src/interpreter.rs
+++ b/SLS_Rust/sls/src/interpreter.rs
@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 
 use crate::lexer::*; // Identifier, Token, TokenString, etc.
+use crate::builtin::load_builtins;
 
 pub type BuiltinFn = fn(&mut InterpreterState) -> bool;
 
@@ -49,6 +50,10 @@ impl InterpreterState {
         }
     }
 
+    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,
@@ -127,15 +132,3 @@ impl InterpreterState {
         self.stack.get(self.stack.len() - 1)
     }
 }
-
-pub fn interpreter_create(load_builtins: fn(&mut InterpreterState) -> bool)
-    -> Option<InterpreterState>
-{
-    let mut state = InterpreterState::new();
-
-    if !load_builtins(&mut state) {
-        return None;
-    }
-
-    Some(state)
-}
diff --git a/SLS_Rust/sls/src/lexer.rs b/SLS_Rust/sls/src/lexer.rs
index 0e0ae86..8b6df6f 100644
--- a/SLS_Rust/sls/src/lexer.rs
+++ b/SLS_Rust/sls/src/lexer.rs
@@ -68,29 +68,29 @@ pub struct Identifier {
 
 #[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),
+    _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>,
+    pub _array: ArrayLiteral,
+    pub _shape: Vec<usize>,
 }
 
 #[derive(Debug, Clone)]
@@ -100,25 +100,25 @@ pub struct TokenString {
 
 #[derive(Debug, Clone)]
 pub struct TypeTuple {
-    pub inputs: Vec<Identifier>,
-    pub outputs: Vec<Identifier>,
+    pub _inputs: Vec<Identifier>,
+    pub _outputs: Vec<Identifier>,
 }
 
 #[derive(Debug, Clone)]
 pub struct StructInline {
-    pub name: String,
-    pub values: Vec<StructValue>,
+    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),
+    _Integer(i64),
+    _Float(f32),
+    _Double(f64),
+    _Boolean(bool),
+    _Character(u8),
+    _String(String),
+    _Token(Token),
 }
 
 #[derive(Debug, Clone)]
@@ -190,7 +190,7 @@ impl LexerInfo {
         !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> {
+    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;
 
@@ -259,7 +259,7 @@ impl LexerInfo {
         Ok(Token::Character(value))
     }
 
-    fn parse_token_string(&mut self, start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
+    fn parse_token_string(&mut self, _start: usize, start_line: usize, start_col: usize) -> LexResult<Token> {
         let mut tokens = Vec::new();
         self.advance(); // skip '{'
 
@@ -399,7 +399,7 @@ impl LexerInfo {
 
         let mut is_float = false;
         let mut is_unsigned = false;
-        let mut bit_size = 64; // default
+        let bit_size: u32;
 
         if c == 'f' {
             is_float = true;
diff --git a/SLS_Rust/sls/src/main.rs b/SLS_Rust/sls/src/main.rs
index 8f942ce..f7a871a 100644
--- a/SLS_Rust/sls/src/main.rs
+++ b/SLS_Rust/sls/src/main.rs
@@ -14,11 +14,6 @@ use repl::repl;
 const SLS_NAME: &str = "SLS_RUST";
 const SLS_VER: &str = "a.0.0";
 
-// Environment variables set via build.rs for commit hash / compiler.
-const GIT_COMMIT_HASH: &str = env!("GIT_COMMIT_HASH", "UNKNOWN");
-const COMPILER_NAME: &str = env!("COMPILER_NAME", "Unknown");
-const COMPILER_VER: &str = env!("COMPILER_VER", "0");
-
 pub fn print_version() {
     let git_hash = option_env!("GIT_COMMIT_HASH").unwrap_or("unknown");
     let compiler = option_env!("COMPILER_NAME").unwrap_or("rustc");
@@ -26,7 +21,7 @@ pub fn print_version() {
     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_RUST) a.0.0 ({git_hash})");
+    println!("YREA SLS ({SLS_NAME}) {SLS_VER} ({git_hash})");
     println!("Compiled with {compiler} {compiler_ver} at {build_date} {build_time}");
 }
 
diff --git a/SLS_Rust/sls/src/repl.rs b/SLS_Rust/sls/src/repl.rs
index dd0718a..c78b658 100644
--- a/SLS_Rust/sls/src/repl.rs
+++ b/SLS_Rust/sls/src/repl.rs
@@ -44,6 +44,9 @@ pub fn repl() -> i32 {
     io::stdout().flush().unwrap();
 
     let mut interpreter = InterpreterState::new();
+    if !interpreter.init() {
+        return 1;
+    }
 
     let stdin = io::stdin();
     let mut buf = String::new();