Hello @Kampfkarren, Sorry for pinging you on this old PR, But I couldn't help but wonder why this got closed. Were there any challenges with the current structure of the parser that makes it impossible to decouple stuff?

I'm working on a gradually typed language that compiles to Lua and can target all runtimes. In some sense, it is similar to TypeScript, But it is not really a superset; While most things in the syntax are close to Lua, and Luau, The language comes with its own quirks such as nil safety, pattern matching, if expression among other things.

Since full-moon has support for all of the target runtimes, It would be nice if it was possible to have an extendable system that would allow having multiple AST types simultaneously.

I would happily work on it with you, Was there ever a plan to also make AST extendable? Either way, I'm probably going to base my compiler's parser on this project and I prefer to contribute it back to this project. There are going to be some generalizations to support a higher-level syntax(such as the macro system and other new features). I know at least part of it could be welcomed here with this PR.

If we want to decouple different language features from the parser we should consider also modularizing the AST itself, Which in return needs to have extendable Stmt, Expression, etc. It would introduce some sort of dynamic dispatching into the mix which I'm not sure is the most desirable thing. On the other hand, if we can't make the AST extendable without introducing too much overhead I need to hard fork it for extension and with each Luau update or new Lua release or on the off chance that this language gets some actual users in the wild, we all get to update our versions respectively.

I haven't read the source thoroughly so I need more time before I can have a solid understanding of the project structure, Have you considered extending plugins to AST itself? If it was part of the plan, what was your idea for tackling it? I would appreciate it if you let me know.