Warning

This post was published 109 days ago. The information described in this article may have changed.

Info

This post is auto-generated from RSS feed The Rust Programming Language Forum - Latest topics. Source: How to pass a type constructor to a declarative macro?

I'm new to macros, and have a one to which I need to pass a type constructor. This variant works ok:

macro_rules! derive_db_conversions_adl_1 {
    ($decl:ident) => {
        impl<P1: serde::Serialize> crate::db::types::DbConversions 
            for $decl<P1>
        {
...
        }
    };
}

but taking an :ident, only accepts an unscoped name. I need to pass a scoped name. Unfortunately using :path in lieu of :ident does not compile. ie this:

macro_rules! derive_db_conversions_adl_1 {
    ($decl:path) => {
        impl<P1: serde::Serialize> crate::db::types::DbConversions
             for $decl<P1>
        {
...
        }
    };
}

gives the error:

    |            for $decl<P1>
    |                     ^ expected one of `!`, `+`, `where`, or `{`
    |

How can this be done?

Thanks!

3 posts - 3 participants

Read full topic

🏷️ rust_feed