rust-lang / rust-lang/reference
Add an example of using a function-like proc macro in expression position
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A-proc-macro
E-Easy
New Content
- Dominant language
- Rust
- Stars
- 1.6k
- Forks
- 607
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Description
A simple example:
use proc_macro::TokenStream;
#[proc_macro]
fn comptime(_input: TokenStream) -> TokenStream {
"1 + 2".parse().unwrap()
}
fn main() {
println!("1 + 2 = {}", comptime!());
}
This particular example isn't particularly interesting, but I don't know proc macros very well yet :)
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Locate the Rust Reference section covering function-like procedural macros and read its surrounding examples. Add a concise example based on the issue’s proc-macro definition and expression-position invocation, then verify that the documentation builds successfully and clearly demonstrates the requested usage.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100