mozilla-central/third_party/rust/proc-macro2/src
Name Description Size
detection.rs ignore 2703
extra.rs Items which do not have a correspondence to any API in the proc_macro crate, but are necessary to include in proc-macro2. 5164
fallback.rs 32707
lib.rs [![github]](https://github.com/dtolnay/proc-macro2)&ensp;[![crates-io]](https://crates.io/crates/proc-macro2)&ensp;[![docs-rs]](crate) [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs <br> A wrapper around the procedural macro API of the compiler's [`proc_macro`] crate. This library serves two purposes: [`proc_macro`]: https://doc.rust-lang.org/proc_macro/ - **Bring proc-macro-like functionality to other contexts like build.rs and main.rs.** Types from `proc_macro` are entirely specific to procedural macros and cannot ever exist in code outside of a procedural macro. Meanwhile `proc_macro2` types may exist anywhere including non-macro code. By developing foundational libraries like [syn] and [quote] against `proc_macro2` rather than `proc_macro`, the procedural macro ecosystem becomes easily applicable to many other use cases and we avoid reimplementing non-macro equivalents of those libraries. - **Make procedural macros unit testable.** As a consequence of being specific to procedural macros, nothing that uses `proc_macro` can be executed from a unit test. In order for helper libraries or components of a macro to be testable in isolation, they must be implemented using `proc_macro2`. [syn]: https://github.com/dtolnay/syn [quote]: https://github.com/dtolnay/quote # Usage The skeleton of a typical procedural macro typically looks like this: ``` extern crate proc_macro; # const IGNORE: &str = stringify! { #[proc_macro_derive(MyDerive)] # }; # #[cfg(wrap_proc_macro)] pub fn my_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream { let input = proc_macro2::TokenStream::from(input); let output: proc_macro2::TokenStream = { /* transform input */ # input }; proc_macro::TokenStream::from(output) } ``` If parsing with [Syn], you'll use [`parse_macro_input!`] instead to propagate parse errors correctly back to the compiler when parsing fails. [`parse_macro_input!`]: https://docs.rs/syn/2.0/syn/macro.parse_macro_input.html # Unstable features The default feature set of proc-macro2 tracks the most recent stable compiler API. Functionality in `proc_macro` that is not yet stable is not exposed by proc-macro2 by default. To opt into the additional APIs available in the most recent nightly compiler, the `procmacro2_semver_exempt` config flag must be passed to rustc. We will polyfill those nightly-only APIs back to Rust 1.56.0. As these are unstable APIs that track the nightly compiler, minor versions of proc-macro2 may make breaking changes to them at any time. ```sh RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo build ``` Note that this must not only be done for your crate, but for any crate that depends on your crate. This infectious nature is intentional, as it serves as a reminder that you are outside of the normal semver guarantees. Semver exempt methods are marked as such in the proc-macro2 documentation. # Thread-Safety Most types in this crate are `!Sync` because the underlying compiler types make use of thread-local memory, meaning they cannot be accessed from a different thread. 45631
location.rs 871
marker.rs 573
parse.rs /") { s = s.advance(4); continue; } else if s.starts_with("/*") && (!s.starts_with("/**") || s.starts_with("/***")) && !s.starts_with("/*!") { match block_comment(s) { Ok((rest, _)) => { s = rest; continue; } Err(Reject) => return s, } } } match byte { b' ' | 0x09..=0x0d => { s = s.advance(1); continue; } b if b.is_ascii() => {} _ => { let ch = s.chars().next().unwrap(); if is_whitespace(ch) { s = s.advance(ch.len_utf8()); continue; } } } return s; } s } fn block_comment(input: Cursor) -> PResult<&str> { if !input.starts_with("/*") { return Err(Reject); } let mut depth = 0usize; let bytes = input.as_bytes(); let mut i = 0usize; let upper = bytes.len() - 1; while i < upper { if bytes[i] == b'/' && bytes[i + 1] == b'*' { depth += 1; i += 1; // eat '*' } else if bytes[i] == b'*' && bytes[i + 1] == b'/' { depth -= 1; if depth == 0 { return Ok((input.advance(i + 2), &input.rest[..i + 2])); } i += 1; // eat '/' } i += 1; } Err(Reject) } fn is_whitespace(ch: char) -> bool { // Rust treats left-to-right mark and right-to-left mark as whitespace ch.is_whitespace() || ch == '\u{200e}' || ch == '\u{200f}' } fn word_break(input: Cursor) -> Result<Cursor, Reject> { match input.chars().next() { Some(ch) if is_ident_continue(ch) => Err(Reject), Some(_) | None => Ok(input), } } // Rustc's representation of a macro expansion error in expression position or // type position. const ERROR: &str = "(/*ERROR 28597
rcvec.rs 2901
wrapper.rs 30381