Support leading pipe in match arms #93
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bors r+ Thanks! This is exactly how I would have done it! The PR description is very useful, I think I'll use this PR as an example of "how to change grammar" when I get to writing a useful contributing md. That said, it probably isn't worth the effort to write such a detailed description every time, though linking to the origninal libsyntax2 is always helpful. |
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93: Support leading pipe in match arms r=matklad a=DJMcNab This adds support for match arms of the form: ```rust <...> | X | Y => <...>, | X => <...>, | 1..2 => <...>, etc ``` # Implementation discussion This just naïvely 'eats' a leading pipe if one is available. The equivalent line in the reference `libsyntax` is in [`parse_arm`](https://github.com/rust-lang/rust/blob/441519536c8bd138e8c651743249acd6814747a1/src/libsyntax/parse/parser.rs#L3552). As noted in the comment linked above, this feature was formally introduced as a result of rust-lang/rfcs#1925. This feature is in active use in the [`rust-analyzer` codebase](https://github.com/matklad/rust-analyzer/blob/c87fcb4ea5874a7307c1d9d1192e923f3ae2c922/crates/ra_syntax/src/syntax_kinds/generated.rs#L231) I have added some tests for this feature, but maybe more would be required EDIT: Always looking for feedback - is this PR description over-engineered? Co-authored-by: Daniel McNab <36049421+djmcnab@users.noreply.github.com>
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This adds support for match arms of the form:
Implementation discussion
This just naïvely 'eats' a leading pipe if one is available. The equivalent line in the reference
libsyntaxis inparse_arm.As noted in the comment linked above, this feature was formally introduced as a result of rust-lang/rfcs#1925. This feature is in active use in the
rust-analyzercodebaseI have added some tests for this feature, but maybe more would be required
EDIT: Always looking for feedback - is this PR description over-engineered?