Fix `-` literal matching in patterns grammar.

Open
#580 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Documentation
Clarity
Mostly clear
Activity status
Stale
Tech stack
rust
Domain
documentation

Research direction

Start by reading the literal metavariable in macros-by-example.md and the LiteralPattern rules in the patterns chapter. Compare the possible MaybeMinusLiteral and LiteralPattern approaches, then check the surrounding grammar text. Done means the syntax for a leading - is represented consistently and the semantic restriction to integers and floats is documented.

Written by the indexing model from the issue text.

Description

A-grammar

The way - is handled in some of the grammar rules is a little messy.

The literal metavariable in macros-by-example.md requires special-casing -. There should probably be a MaybeMinusLiteral rule somewhere (maybe in the patterns chapter?). Or maybe LiteralPattern should be rewritten to indicate that - can appear in front of any literal. That is, -"foo" is valid syntactically. The text should then mention the semantic restriction that - may only apply to integers and floats in patterns.

Dominant language
Rust
Stars
1.6k
Forks
607
Avg merge
1d 1h
Merged PRs (30d)
12

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from rust-lang/reference

All issues in rust-lang/reference

Similar issues

More Rust issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.