If Odin Had Macros

Summary

I sometimes get asked if Odin has any plans to add hygienic macros or some other similar construct. My general, and now (in)famous, answer is to many such questions is: No. I am not against macros nor metaprogramming in general, and in fact I do make metaprograms quite often (i.e. programs that make/analyse a program). However my approach with the design of Odin has been extremely pragmatic. I commonly ask people who ask for such things what are they specifically trying to solve? Usually they are not trying to do anything whatsoever and are just thinking about non-existent hypotheticals. However, in the cases when people are trying to do something that they believe they need a macro for, Odin usually has a different approach to doing it and it is usually much better and more suited for the specific need of the problem. This is the surprising thing about designing Odin, I was expecting I would need some form of compile-time metaprogramming at the language level, be it hygienic macros, compile-time execution, or even complete compile-time AST modification. But every problem I came across, I find a better solution that could be solved with a different language construct or idiom. My original hypothesis in general has been shown to be wrong. A Possible Case for Macros in Odin n.b. This is all hypothetical, and the construct is very unlikely to happen in Odin One of the best cases for a macro-like construct that I can think of which Odin does not support would be push-based iterators. Since Go 1.23, it now has a way of doing push-based iterators. I’ve written on this topic before (Why People are Angry over Go 1.23 Iterators) and how they work. The main issue I have with them, and which many other individuals have complaints with too, is that they effectively rely on 3-levels deep of closures. You have a function that returns a closure that in turn takes in a closure which is automatically and implicitly generated from the body of a for range loop. This is honestly not go...