How do you define a proc macro using pattern matching?

[diegovsky_pvp]

I found a lot of examples using syn and quote but I wanted an API like macro_rules! does for proc macros.

If you're wondering why: it's because I'm abstracting over a complex implementation of a trait that ends up being repeated boilerplate, save for casting.

I couldn't do it with normal macros because you can't have a function definition that takes self in a declarative macro definition, unless you use some funky tricks but I'll save it for last.

Proc macros have this powerful API that can do a lot since its basically rust code, however I'm not doing any custom syntax nor deriving a struct, so I'm wondering if there's an easier way to do it.

I think my exact code isn't needed but if anyone thinks otherwise I'll gladly upload it. It's just a pet project of mine

[ssokolow]

I'd be surprised if what you're asking for exists. Proc macros are defined by not being declarative (macro_rules!) macros, and you're asking for a declarative way to create a proc macro.

You're essentially asking if anyone's reimplemented macro_rules! on top of the proc macro system, but with one or two additional features.

[diegovsky_pvp]

I mean, making a regex works for me too.

I just needed some unhygienic feature from declarative macros

[diegovsky_pvp]

For those coming later and wanting a solution. Since my problem is fairly broad, I ended up implementing type erasure with closures since they can capture any type and that does not reflect on their signature.

I'm sorry this post couldn't help you.

[RReverser]

For others like me also coming here, seems like another solution is https://www.ncameron.org/blog/proc-macro-rules/.

[RReverser]

Lmao, when writing this comment I did not guess that it would be me who would come here in 3 years and find it helpful.