One of the things I decided to do with finl was to formalize on LaTeX’s syntax. No more shifting category codes, Separating out the lexer definition of commands

One of the things I decided to do with finl was to formalize on LaTeX’s syntax. No more shifting category codes, Separating out the lexer definition of commands from their meaning also means that tooling becomes simpler. Throw in proper variables so there’s no longer the need for redefining macros to emulate variables and it becomes a little more tractable. That said, even with these restrictions, writing a good lexer/parser of a LaTeX-like syntax is still a challenge (and made all the slower by the needs to earn money, spend time with my kids and have other joys in life).