| commit | 1fc4b67256ef0691d67057231a3f3630be0ef6e6 | [log] [tgz] |
|---|---|---|
| author | Travis Cross <tc@traviscross.com> | Wed May 14 12:39:49 2025 +0000 |
| committer | Eric Huss <eric@huss.org> | Thu May 15 05:56:33 2025 -0700 |
| tree | f44bd01acf2404de88a1c7f2d0656f8e39a22f84 | |
| parent | 048d75aa5f881235c88256b6d3fdaaaeadb5aa32 [diff] |
Fix grammar for `LiteralPattern` regarding `-`
We had documented that only numeric literals in patterns can be
prefixed by `-` (minus), but the Rust parser happily accepts a minus
ahead of all literals in patterns. E.g.:
```rust
match () {
-true | -false => (),
-'x' => (),
-b'x' => (),
-"x" => (),
-r"x" => (),
-br"x" => (),
-c"x" => (),
-cr"x" => (),
-1 => (),
-1.1 => (),
}
```
In the compiler, this happens in `Parser::parse_literal_maybe_minus`
and `Token::can_begin_literal_maybe_minus`.
Let's fix this by defining `LiteralPattern` as a `LiteralExpression`
optionally prefixed by the minus sign. This better matches how the
`rustc` AST models this.
This document is the primary reference for the Rust programming language.
First, ensure that you have a recent copy of the nightly Rust compiler installed, as this is needed in order to run the tests:
rustup toolchain install nightly
Now, ensure you have mdbook installed, as this is needed in order to build the Reference:
cargo install --locked mdbook
To build the Reference, first clone the project:
git clone https://github.com/rust-lang/reference.git
(Alternatively, if you don't want to use git, download a ZIP file of the project, extract it using your preferred tool, and rename the top-level directory to reference.)
Now change your current directory to the working directory:
cd reference
To test all of the code examples in the Reference, run:
mdbook test
For authors, consider using the server functionality which supports automatic reload.
To build the Reference locally (in build/) and open it in a web browser, run:
SPEC_RELATIVE=0 mdbook build --open
This will open a browser with a websocket live-link to automatically reload whenever the source is updated.
You can also use mdbook's live webserver option, which will automatically rebuild the book and reload your web browser whenever a source file is modified:
SPEC_RELATIVE=0 mdbook serve --open
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The published site at https://doc.rust-lang.org/reference/ (or local docs using rustup doc) does not set this, which means it will use relative links which supports offline viewing and links to the correct version (for example, links in https://doc.rust-lang.org/1.81.0/reference/ will stay within the 1.81.0 directory).
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