# YREA SLS
*Kyler Olsen*  
*October 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.