> I feel like the plethora of (partially incompatible) extensions make the language very complicated and messy. There is no single Haskell. Each file can be GHC Haskell with OverloadedStrings or GADTs or ....
Aren't macros, especially proc macros these days in Rust having the same effect? Personally I feel like this is a tradeoff every language has to play with: you either limit to a special way of writing, or adding some sort of ad-hoc system that enables rewriting syntax and even to a degree, semantics.
Anecdotally, proc macros just aren't that common. Almost every Haskell tutorial I read introduces language extensions, and it seems like many users have a set of extensions that they always enable by default. I don't think proc macros are really comparable in that sense, although maybe they will be in the future?
Overly powerful proc-macros aren't in common use; most common proc-macros are either ones that automatically Derive a trait, or ones that serves as attributes on methods or functions and perform some transformation of the source code (without introducing a DSL)
Aren't macros, especially proc macros these days in Rust having the same effect? Personally I feel like this is a tradeoff every language has to play with: you either limit to a special way of writing, or adding some sort of ad-hoc system that enables rewriting syntax and even to a degree, semantics.