title_body: What are some examples of mathematical conlangs?
upvoted_answer: There's a language based on stack-based programming languages (like Forth) that eliminates syntactic ambiguity called Fith. The name is a deliberate pun on Forth.
  
  FrathWiki
  2019 Smiley award page
  Fith grammar (archived)
  
  Basically, when parsing the language you have a stack of objects that you have to keep track of, as well as some global state like the default number that can be explicitly changed.
  The idea of layering a human language on top of a Forth-like grammar is flexible enough that you could extend Fith or make radically different design decisions without losing some of its nice properties.