I took a look at that attached PDF and understood the task. I have hand written LALR parsers before, for other projects, and I'm very familiar with language parsing, tokenizing and formulating several syntaxes. In this case I can see that the goal is to try and mimic a "postscript" type syntax and run a repl with the provided code. I'll read through the rest of document, but meanwhile you can message me with with any additional info that I should know about. Thanks.