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lib.rs
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linux-6.19.14/rust/proc-macro2/lib.rs
1// SPDX-License-Identifier: Apache-2.0 OR MIT 2 3// When fixdep scans this, it will find this string `CONFIG_RUSTC_VERSION_TEXT` 4// and thus add a dependency on `include/config/RUSTC_VERSION_TEXT`, which is 5// touched by Kconfig when the version string from the compiler changes. 6 7//! [![github]](https://github.com/dtolnay/proc-macro2) [![crates-io]](https://crates.io/crates/proc-macro2) [![docs-rs]](crate) 8//! 9//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github 10//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust 11//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs 12//! 13//! <br> 14//! 15//! A wrapper around the procedural macro API of the compiler's [`proc_macro`] 16//! crate. This library serves two purposes: 17//! 18//! - **Bring proc-macro-like functionality to other contexts like build.rs and 19//! main.rs.** Types from `proc_macro` are entirely specific to procedural 20//! macros and cannot ever exist in code outside of a procedural macro. 21//! Meanwhile `proc_macro2` types may exist anywhere including non-macro code. 22//! By developing foundational libraries like [syn] and [quote] against 23//! `proc_macro2` rather than `proc_macro`, the procedural macro ecosystem 24//! becomes easily applicable to many other use cases and we avoid 25//! reimplementing non-macro equivalents of those libraries. 26//! 27//! - **Make procedural macros unit testable.** As a consequence of being 28//! specific to procedural macros, nothing that uses `proc_macro` can be 29//! executed from a unit test. In order for helper libraries or components of 30//! a macro to be testable in isolation, they must be implemented using 31//! `proc_macro2`. 32//! 33//! [syn]: https://github.com/dtolnay/syn 34//! [quote]: https://github.com/dtolnay/quote 35//! 36//! # Usage 37//! 38//! The skeleton of a typical procedural macro typically looks like this: 39//! 40//! ``` 41//! extern crate proc_macro; 42//! 43//! # const IGNORE: &str = stringify! { 44//! #[proc_macro_derive(MyDerive)] 45//! # }; 46//! # #[cfg(wrap_proc_macro)] 47//! pub fn my_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream { 48//! let input = proc_macro2::TokenStream::from(input); 49//! 50//! let output: proc_macro2::TokenStream = { 51//! /* transform input */ 52//! # input 53//! }; 54//! 55//! proc_macro::TokenStream::from(output) 56//! } 57//! ``` 58//! 59//! If parsing with [Syn], you'll use [`parse_macro_input!`] instead to 60//! propagate parse errors correctly back to the compiler when parsing fails. 61//! 62//! [`parse_macro_input!`]: https://docs.rs/syn/2.0/syn/macro.parse_macro_input.html 63//! 64//! # Unstable features 65//! 66//! The default feature set of proc-macro2 tracks the most recent stable 67//! compiler API. Functionality in `proc_macro` that is not yet stable is not 68//! exposed by proc-macro2 by default. 69//! 70//! To opt into the additional APIs available in the most recent nightly 71//! compiler, the `procmacro2_semver_exempt` config flag must be passed to 72//! rustc. We will polyfill those nightly-only APIs back to Rust 1.56.0. As 73//! these are unstable APIs that track the nightly compiler, minor versions of 74//! proc-macro2 may make breaking changes to them at any time. 75//! 76//! ```sh 77//! RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo build 78//! ``` 79//! 80//! Note that this must not only be done for your crate, but for any crate that 81//! depends on your crate. This infectious nature is intentional, as it serves 82//! as a reminder that you are outside of the normal semver guarantees. 83//! 84//! Semver exempt methods are marked as such in the proc-macro2 documentation. 85//! 86//! # Thread-Safety 87//! 88//! Most types in this crate are `!Sync` because the underlying compiler 89//! types make use of thread-local memory, meaning they cannot be accessed from 90//! a different thread. 91 92// Proc-macro2 types in rustdoc of other crates get linked to here. 93#![doc(html_root_url = "https://docs.rs/proc-macro2/1.0.101")] 94#![cfg_attr(any(proc_macro_span, super_unstable), feature(proc_macro_span))] 95#![cfg_attr(super_unstable, feature(proc_macro_def_site))] 96#![cfg_attr(docsrs, feature(doc_cfg))] 97#![deny(unsafe_op_in_unsafe_fn)] 98#![allow( 99 clippy::cast_lossless, 100 clippy::cast_possible_truncation, 101 clippy::checked_conversions, 102 clippy::doc_markdown, 103 clippy::elidable_lifetime_names, 104 clippy::incompatible_msrv, 105 clippy::items_after_statements, 106 clippy::iter_without_into_iter, 107 clippy::let_underscore_untyped, 108 clippy::manual_assert, 109 clippy::manual_range_contains, 110 clippy::missing_panics_doc, 111 clippy::missing_safety_doc, 112 clippy::must_use_candidate, 113 clippy::needless_doctest_main, 114 clippy::needless_lifetimes, 115 clippy::new_without_default, 116 clippy::return_self_not_must_use, 117 clippy::shadow_unrelated, 118 clippy::trivially_copy_pass_by_ref, 119 clippy::unnecessary_wraps, 120 clippy::unused_self, 121 clippy::used_underscore_binding, 122 clippy::vec_init_then_push 123)] 124#![allow(unknown_lints, mismatched_lifetime_syntaxes)] 125 126#[cfg(all(procmacro2_semver_exempt, wrap_proc_macro, not(super_unstable)))] 127compile_error! {"\ 128 Something is not right. If you've tried to turn on \ 129 procmacro2_semver_exempt, you need to ensure that it \ 130 is turned on for the compilation of the proc-macro2 \ 131 build script as well. 132"} 133 134#[cfg(all( 135 procmacro2_nightly_testing, 136 feature = "proc-macro", 137 not(proc_macro_span) 138))] 139compile_error! {"\ 140 Build script probe failed to compile. 141"} 142 143extern crate alloc; 144 145#[cfg(feature = "proc-macro")] 146extern crate proc_macro; 147 148mod marker; 149mod parse; 150mod probe; 151mod rcvec; 152 153#[cfg(wrap_proc_macro)] 154mod detection; 155 156// Public for proc_macro2::fallback::force() and unforce(), but those are quite 157// a niche use case so we omit it from rustdoc. 158#[doc(hidden)] 159pub mod fallback; 160 161pub mod extra; 162 163#[cfg(not(wrap_proc_macro))] 164use crate::fallback as imp; 165#[path = "wrapper.rs"] 166#[cfg(wrap_proc_macro)] 167mod imp; 168 169#[cfg(span_locations)] 170mod location; 171 172use crate::extra::DelimSpan; 173use crate::marker::{ProcMacroAutoTraits, MARKER}; 174use core::cmp::Ordering; 175use core::fmt::{self, Debug, Display}; 176use core::hash::{Hash, Hasher}; 177#[cfg(span_locations)] 178use core::ops::Range; 179use core::ops::RangeBounds; 180use core::str::FromStr; 181use std::error::Error; 182use std::ffi::CStr; 183#[cfg(span_locations)] 184use std::path::PathBuf; 185 186#[cfg(span_locations)] 187#[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))] 188pub use crate::location::LineColumn; 189 190/// An abstract stream of tokens, or more concretely a sequence of token trees. 191/// 192/// This type provides interfaces for iterating over token trees and for 193/// collecting token trees into one stream. 194/// 195/// Token stream is both the input and output of `#[proc_macro]`, 196/// `#[proc_macro_attribute]` and `#[proc_macro_derive]` definitions. 197#[derive(Clone)] 198pub struct TokenStream { 199 inner: imp::TokenStream, 200 _marker: ProcMacroAutoTraits, 201} 202 203/// Error returned from `TokenStream::from_str`. 204pub struct LexError { 205 inner: imp::LexError, 206 _marker: ProcMacroAutoTraits, 207} 208 209impl TokenStream { 210 fn _new(inner: imp::TokenStream) -> Self { 211 TokenStream { 212 inner, 213 _marker: MARKER, 214 } 215 } 216 217 fn _new_fallback(inner: fallback::TokenStream) -> Self { 218 TokenStream { 219 inner: imp::TokenStream::from(inner), 220 _marker: MARKER, 221 } 222 } 223 224 /// Returns an empty `TokenStream` containing no token trees. 225 pub fn new() -> Self { 226 TokenStream::_new(imp::TokenStream::new()) 227 } 228 229 /// Checks if this `TokenStream` is empty. 230 pub fn is_empty(&self) -> bool { 231 self.inner.is_empty() 232 } 233} 234 235/// `TokenStream::default()` returns an empty stream, 236/// i.e. this is equivalent with `TokenStream::new()`. 237impl Default for TokenStream { 238 fn default() -> Self { 239 TokenStream::new() 240 } 241} 242 243/// Attempts to break the string into tokens and parse those tokens into a token 244/// stream. 245/// 246/// May fail for a number of reasons, for example, if the string contains 247/// unbalanced delimiters or characters not existing in the language. 248/// 249/// NOTE: Some errors may cause panics instead of returning `LexError`. We 250/// reserve the right to change these errors into `LexError`s later. 251impl FromStr for TokenStream { 252 type Err = LexError; 253 254 fn from_str(src: &str) -> Result<TokenStream, LexError> { 255 match imp::TokenStream::from_str_checked(src) { 256 Ok(tokens) => Ok(TokenStream::_new(tokens)), 257 Err(lex) => Err(LexError { 258 inner: lex, 259 _marker: MARKER, 260 }), 261 } 262 } 263} 264 265#[cfg(feature = "proc-macro")] 266#[cfg_attr(docsrs, doc(cfg(feature = "proc-macro")))] 267impl From<proc_macro::TokenStream> for TokenStream { 268 fn from(inner: proc_macro::TokenStream) -> Self { 269 TokenStream::_new(imp::TokenStream::from(inner)) 270 } 271} 272 273#[cfg(feature = "proc-macro")] 274#[cfg_attr(docsrs, doc(cfg(feature = "proc-macro")))] 275impl From<TokenStream> for proc_macro::TokenStream { 276 fn from(inner: TokenStream) -> Self { 277 proc_macro::TokenStream::from(inner.inner) 278 } 279} 280 281impl From<TokenTree> for TokenStream { 282 fn from(token: TokenTree) -> Self { 283 TokenStream::_new(imp::TokenStream::from(token)) 284 } 285} 286 287impl Extend<TokenTree> for TokenStream { 288 fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I) { 289 self.inner.extend(streams); 290 } 291} 292 293impl Extend<TokenStream> for TokenStream { 294 fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) { 295 self.inner 296 .extend(streams.into_iter().map(|stream| stream.inner)); 297 } 298} 299 300/// Collects a number of token trees into a single stream. 301impl FromIterator<TokenTree> for TokenStream { 302 fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self { 303 TokenStream::_new(streams.into_iter().collect()) 304 } 305} 306impl FromIterator<TokenStream> for TokenStream { 307 fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self { 308 TokenStream::_new(streams.into_iter().map(|i| i.inner).collect()) 309 } 310} 311 312/// Prints the token stream as a string that is supposed to be losslessly 313/// convertible back into the same token stream (modulo spans), except for 314/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative 315/// numeric literals. 316impl Display for TokenStream { 317 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 318 Display::fmt(&self.inner, f) 319 } 320} 321 322/// Prints token in a form convenient for debugging. 323impl Debug for TokenStream { 324 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 325 Debug::fmt(&self.inner, f) 326 } 327} 328 329impl LexError { 330 pub fn span(&self) -> Span { 331 Span::_new(self.inner.span()) 332 } 333} 334 335impl Debug for LexError { 336 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 337 Debug::fmt(&self.inner, f) 338 } 339} 340 341impl Display for LexError { 342 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 343 Display::fmt(&self.inner, f) 344 } 345} 346 347impl Error for LexError {} 348 349/// A region of source code, along with macro expansion information. 350#[derive(Copy, Clone)] 351pub struct Span { 352 inner: imp::Span, 353 _marker: ProcMacroAutoTraits, 354} 355 356impl Span { 357 fn _new(inner: imp::Span) -> Self { 358 Span { 359 inner, 360 _marker: MARKER, 361 } 362 } 363 364 fn _new_fallback(inner: fallback::Span) -> Self { 365 Span { 366 inner: imp::Span::from(inner), 367 _marker: MARKER, 368 } 369 } 370 371 /// The span of the invocation of the current procedural macro. 372 /// 373 /// Identifiers created with this span will be resolved as if they were 374 /// written directly at the macro call location (call-site hygiene) and 375 /// other code at the macro call site will be able to refer to them as well. 376 pub fn call_site() -> Self { 377 Span::_new(imp::Span::call_site()) 378 } 379 380 /// The span located at the invocation of the procedural macro, but with 381 /// local variables, labels, and `$crate` resolved at the definition site 382 /// of the macro. This is the same hygiene behavior as `macro_rules`. 383 pub fn mixed_site() -> Self { 384 Span::_new(imp::Span::mixed_site()) 385 } 386 387 /// A span that resolves at the macro definition site. 388 /// 389 /// This method is semver exempt and not exposed by default. 390 #[cfg(procmacro2_semver_exempt)] 391 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))] 392 pub fn def_site() -> Self { 393 Span::_new(imp::Span::def_site()) 394 } 395 396 /// Creates a new span with the same line/column information as `self` but 397 /// that resolves symbols as though it were at `other`. 398 pub fn resolved_at(&self, other: Span) -> Span { 399 Span::_new(self.inner.resolved_at(other.inner)) 400 } 401 402 /// Creates a new span with the same name resolution behavior as `self` but 403 /// with the line/column information of `other`. 404 pub fn located_at(&self, other: Span) -> Span { 405 Span::_new(self.inner.located_at(other.inner)) 406 } 407 408 /// Convert `proc_macro2::Span` to `proc_macro::Span`. 409 /// 410 /// This method is available when building with a nightly compiler, or when 411 /// building with rustc 1.29+ *without* semver exempt features. 412 /// 413 /// # Panics 414 /// 415 /// Panics if called from outside of a procedural macro. Unlike 416 /// `proc_macro2::Span`, the `proc_macro::Span` type can only exist within 417 /// the context of a procedural macro invocation. 418 #[cfg(wrap_proc_macro)] 419 pub fn unwrap(self) -> proc_macro::Span { 420 self.inner.unwrap() 421 } 422 423 // Soft deprecated. Please use Span::unwrap. 424 #[cfg(wrap_proc_macro)] 425 #[doc(hidden)] 426 pub fn unstable(self) -> proc_macro::Span { 427 self.unwrap() 428 } 429 430 /// Returns the span's byte position range in the source file. 431 /// 432 /// This method requires the `"span-locations"` feature to be enabled. 433 /// 434 /// When executing in a procedural macro context, the returned range is only 435 /// accurate if compiled with a nightly toolchain. The stable toolchain does 436 /// not have this information available. When executing outside of a 437 /// procedural macro, such as main.rs or build.rs, the byte range is always 438 /// accurate regardless of toolchain. 439 #[cfg(span_locations)] 440 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))] 441 pub fn byte_range(&self) -> Range<usize> { 442 self.inner.byte_range() 443 } 444 445 /// Get the starting line/column in the source file for this span. 446 /// 447 /// This method requires the `"span-locations"` feature to be enabled. 448 /// 449 /// When executing in a procedural macro context, the returned line/column 450 /// are only meaningful if compiled with a nightly toolchain. The stable 451 /// toolchain does not have this information available. When executing 452 /// outside of a procedural macro, such as main.rs or build.rs, the 453 /// line/column are always meaningful regardless of toolchain. 454 #[cfg(span_locations)] 455 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))] 456 pub fn start(&self) -> LineColumn { 457 self.inner.start() 458 } 459 460 /// Get the ending line/column in the source file for this span. 461 /// 462 /// This method requires the `"span-locations"` feature to be enabled. 463 /// 464 /// When executing in a procedural macro context, the returned line/column 465 /// are only meaningful if compiled with a nightly toolchain. The stable 466 /// toolchain does not have this information available. When executing 467 /// outside of a procedural macro, such as main.rs or build.rs, the 468 /// line/column are always meaningful regardless of toolchain. 469 #[cfg(span_locations)] 470 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))] 471 pub fn end(&self) -> LineColumn { 472 self.inner.end() 473 } 474 475 /// The path to the source file in which this span occurs, for display 476 /// purposes. 477 /// 478 /// This might not correspond to a valid file system path. It might be 479 /// remapped, or might be an artificial path such as `"<macro expansion>"`. 480 #[cfg(span_locations)] 481 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))] 482 pub fn file(&self) -> String { 483 self.inner.file() 484 } 485 486 /// The path to the source file in which this span occurs on disk. 487 /// 488 /// This is the actual path on disk. It is unaffected by path remapping. 489 /// 490 /// This path should not be embedded in the output of the macro; prefer 491 /// `file()` instead. 492 #[cfg(span_locations)] 493 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))] 494 pub fn local_file(&self) -> Option<PathBuf> { 495 self.inner.local_file() 496 } 497 498 /// Create a new span encompassing `self` and `other`. 499 /// 500 /// Returns `None` if `self` and `other` are from different files. 501 /// 502 /// Warning: the underlying [`proc_macro::Span::join`] method is 503 /// nightly-only. When called from within a procedural macro not using a 504 /// nightly compiler, this method will always return `None`. 505 pub fn join(&self, other: Span) -> Option<Span> { 506 self.inner.join(other.inner).map(Span::_new) 507 } 508 509 /// Compares two spans to see if they're equal. 510 /// 511 /// This method is semver exempt and not exposed by default. 512 #[cfg(procmacro2_semver_exempt)] 513 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))] 514 pub fn eq(&self, other: &Span) -> bool { 515 self.inner.eq(&other.inner) 516 } 517 518 /// Returns the source text behind a span. This preserves the original 519 /// source code, including spaces and comments. It only returns a result if 520 /// the span corresponds to real source code. 521 /// 522 /// Note: The observable result of a macro should only rely on the tokens 523 /// and not on this source text. The result of this function is a best 524 /// effort to be used for diagnostics only. 525 pub fn source_text(&self) -> Option<String> { 526 self.inner.source_text() 527 } 528} 529 530/// Prints a span in a form convenient for debugging. 531impl Debug for Span { 532 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 533 Debug::fmt(&self.inner, f) 534 } 535} 536 537/// A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`). 538#[derive(Clone)] 539pub enum TokenTree { 540 /// A token stream surrounded by bracket delimiters. 541 Group(Group), 542 /// An identifier. 543 Ident(Ident), 544 /// A single punctuation character (`+`, `,`, `$`, etc.). 545 Punct(Punct), 546 /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc. 547 Literal(Literal), 548} 549 550impl TokenTree { 551 /// Returns the span of this tree, delegating to the `span` method of 552 /// the contained token or a delimited stream. 553 pub fn span(&self) -> Span { 554 match self { 555 TokenTree::Group(t) => t.span(), 556 TokenTree::Ident(t) => t.span(), 557 TokenTree::Punct(t) => t.span(), 558 TokenTree::Literal(t) => t.span(), 559 } 560 } 561 562 /// Configures the span for *only this token*. 563 /// 564 /// Note that if this token is a `Group` then this method will not configure 565 /// the span of each of the internal tokens, this will simply delegate to 566 /// the `set_span` method of each variant. 567 pub fn set_span(&mut self, span: Span) { 568 match self { 569 TokenTree::Group(t) => t.set_span(span), 570 TokenTree::Ident(t) => t.set_span(span), 571 TokenTree::Punct(t) => t.set_span(span), 572 TokenTree::Literal(t) => t.set_span(span), 573 } 574 } 575} 576 577impl From<Group> for TokenTree { 578 fn from(g: Group) -> Self { 579 TokenTree::Group(g) 580 } 581} 582 583impl From<Ident> for TokenTree { 584 fn from(g: Ident) -> Self { 585 TokenTree::Ident(g) 586 } 587} 588 589impl From<Punct> for TokenTree { 590 fn from(g: Punct) -> Self { 591 TokenTree::Punct(g) 592 } 593} 594 595impl From<Literal> for TokenTree { 596 fn from(g: Literal) -> Self { 597 TokenTree::Literal(g) 598 } 599} 600 601/// Prints the token tree as a string that is supposed to be losslessly 602/// convertible back into the same token tree (modulo spans), except for 603/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative 604/// numeric literals. 605impl Display for TokenTree { 606 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 607 match self { 608 TokenTree::Group(t) => Display::fmt(t, f), 609 TokenTree::Ident(t) => Display::fmt(t, f), 610 TokenTree::Punct(t) => Display::fmt(t, f), 611 TokenTree::Literal(t) => Display::fmt(t, f), 612 } 613 } 614} 615 616/// Prints token tree in a form convenient for debugging. 617impl Debug for TokenTree { 618 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 619 // Each of these has the name in the struct type in the derived debug, 620 // so don't bother with an extra layer of indirection 621 match self { 622 TokenTree::Group(t) => Debug::fmt(t, f), 623 TokenTree::Ident(t) => { 624 let mut debug = f.debug_struct("Ident"); 625 debug.field("sym", &format_args!("{}", t)); 626 imp::debug_span_field_if_nontrivial(&mut debug, t.span().inner); 627 debug.finish() 628 } 629 TokenTree::Punct(t) => Debug::fmt(t, f), 630 TokenTree::Literal(t) => Debug::fmt(t, f), 631 } 632 } 633} 634 635/// A delimited token stream. 636/// 637/// A `Group` internally contains a `TokenStream` which is surrounded by 638/// `Delimiter`s. 639#[derive(Clone)] 640pub struct Group { 641 inner: imp::Group, 642} 643 644/// Describes how a sequence of token trees is delimited. 645#[derive(Copy, Clone, Debug, Eq, PartialEq)] 646pub enum Delimiter { 647 /// `( ... )` 648 Parenthesis, 649 /// `{ ... }` 650 Brace, 651 /// `[ ... ]` 652 Bracket, 653 /// `∅ ... ∅` 654 /// 655 /// An invisible delimiter, that may, for example, appear around tokens 656 /// coming from a "macro variable" `$var`. It is important to preserve 657 /// operator priorities in cases like `$var * 3` where `$var` is `1 + 2`. 658 /// Invisible delimiters may not survive roundtrip of a token stream through 659 /// a string. 660 /// 661 /// <div class="warning"> 662 /// 663 /// Note: rustc currently can ignore the grouping of tokens delimited by `None` in the output 664 /// of a proc_macro. Only `None`-delimited groups created by a macro_rules macro in the input 665 /// of a proc_macro macro are preserved, and only in very specific circumstances. 666 /// Any `None`-delimited groups (re)created by a proc_macro will therefore not preserve 667 /// operator priorities as indicated above. The other `Delimiter` variants should be used 668 /// instead in this context. This is a rustc bug. For details, see 669 /// [rust-lang/rust#67062](https://github.com/rust-lang/rust/issues/67062). 670 /// 671 /// </div> 672 None, 673} 674 675impl Group { 676 fn _new(inner: imp::Group) -> Self { 677 Group { inner } 678 } 679 680 fn _new_fallback(inner: fallback::Group) -> Self { 681 Group { 682 inner: imp::Group::from(inner), 683 } 684 } 685 686 /// Creates a new `Group` with the given delimiter and token stream. 687 /// 688 /// This constructor will set the span for this group to 689 /// `Span::call_site()`. To change the span you can use the `set_span` 690 /// method below. 691 pub fn new(delimiter: Delimiter, stream: TokenStream) -> Self { 692 Group { 693 inner: imp::Group::new(delimiter, stream.inner), 694 } 695 } 696 697 /// Returns the punctuation used as the delimiter for this group: a set of 698 /// parentheses, square brackets, or curly braces. 699 pub fn delimiter(&self) -> Delimiter { 700 self.inner.delimiter() 701 } 702 703 /// Returns the `TokenStream` of tokens that are delimited in this `Group`. 704 /// 705 /// Note that the returned token stream does not include the delimiter 706 /// returned above. 707 pub fn stream(&self) -> TokenStream { 708 TokenStream::_new(self.inner.stream()) 709 } 710 711 /// Returns the span for the delimiters of this token stream, spanning the 712 /// entire `Group`. 713 /// 714 /// ```text 715 /// pub fn span(&self) -> Span { 716 /// ^^^^^^^ 717 /// ``` 718 pub fn span(&self) -> Span { 719 Span::_new(self.inner.span()) 720 } 721 722 /// Returns the span pointing to the opening delimiter of this group. 723 /// 724 /// ```text 725 /// pub fn span_open(&self) -> Span { 726 /// ^ 727 /// ``` 728 pub fn span_open(&self) -> Span { 729 Span::_new(self.inner.span_open()) 730 } 731 732 /// Returns the span pointing to the closing delimiter of this group. 733 /// 734 /// ```text 735 /// pub fn span_close(&self) -> Span { 736 /// ^ 737 /// ``` 738 pub fn span_close(&self) -> Span { 739 Span::_new(self.inner.span_close()) 740 } 741 742 /// Returns an object that holds this group's `span_open()` and 743 /// `span_close()` together (in a more compact representation than holding 744 /// those 2 spans individually). 745 pub fn delim_span(&self) -> DelimSpan { 746 DelimSpan::new(&self.inner) 747 } 748 749 /// Configures the span for this `Group`'s delimiters, but not its internal 750 /// tokens. 751 /// 752 /// This method will **not** set the span of all the internal tokens spanned 753 /// by this group, but rather it will only set the span of the delimiter 754 /// tokens at the level of the `Group`. 755 pub fn set_span(&mut self, span: Span) { 756 self.inner.set_span(span.inner); 757 } 758} 759 760/// Prints the group as a string that should be losslessly convertible back 761/// into the same group (modulo spans), except for possibly `TokenTree::Group`s 762/// with `Delimiter::None` delimiters. 763impl Display for Group { 764 fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { 765 Display::fmt(&self.inner, formatter) 766 } 767} 768 769impl Debug for Group { 770 fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { 771 Debug::fmt(&self.inner, formatter) 772 } 773} 774 775/// A `Punct` is a single punctuation character like `+`, `-` or `#`. 776/// 777/// Multicharacter operators like `+=` are represented as two instances of 778/// `Punct` with different forms of `Spacing` returned. 779#[derive(Clone)] 780pub struct Punct { 781 ch: char, 782 spacing: Spacing, 783 span: Span, 784} 785 786/// Whether a `Punct` is followed immediately by another `Punct` or followed by 787/// another token or whitespace. 788#[derive(Copy, Clone, Debug, Eq, PartialEq)] 789pub enum Spacing { 790 /// E.g. `+` is `Alone` in `+ =`, `+ident` or `+()`. 791 Alone, 792 /// E.g. `+` is `Joint` in `+=` or `'` is `Joint` in `'#`. 793 /// 794 /// Additionally, single quote `'` can join with identifiers to form 795 /// lifetimes `'ident`. 796 Joint, 797} 798 799impl Punct { 800 /// Creates a new `Punct` from the given character and spacing. 801 /// 802 /// The `ch` argument must be a valid punctuation character permitted by the 803 /// language, otherwise the function will panic. 804 /// 805 /// The returned `Punct` will have the default span of `Span::call_site()` 806 /// which can be further configured with the `set_span` method below. 807 pub fn new(ch: char, spacing: Spacing) -> Self { 808 if let '!' | '#' | '$' | '%' | '&' | '\'' | '*' | '+' | ',' | '-' | '.' | '/' | ':' | ';' 809 | '<' | '=' | '>' | '?' | '@' | '^' | '|' | '~' = ch 810 { 811 Punct { 812 ch, 813 spacing, 814 span: Span::call_site(), 815 } 816 } else { 817 panic!("unsupported proc macro punctuation character {:?}", ch); 818 } 819 } 820 821 /// Returns the value of this punctuation character as `char`. 822 pub fn as_char(&self) -> char { 823 self.ch 824 } 825 826 /// Returns the spacing of this punctuation character, indicating whether 827 /// it's immediately followed by another `Punct` in the token stream, so 828 /// they can potentially be combined into a multicharacter operator 829 /// (`Joint`), or it's followed by some other token or whitespace (`Alone`) 830 /// so the operator has certainly ended. 831 pub fn spacing(&self) -> Spacing { 832 self.spacing 833 } 834 835 /// Returns the span for this punctuation character. 836 pub fn span(&self) -> Span { 837 self.span 838 } 839 840 /// Configure the span for this punctuation character. 841 pub fn set_span(&mut self, span: Span) { 842 self.span = span; 843 } 844} 845 846/// Prints the punctuation character as a string that should be losslessly 847/// convertible back into the same character. 848impl Display for Punct { 849 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 850 Display::fmt(&self.ch, f) 851 } 852} 853 854impl Debug for Punct { 855 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { 856 let mut debug = fmt.debug_struct("Punct"); 857 debug.field("char", &self.ch); 858 debug.field("spacing", &self.spacing); 859 imp::debug_span_field_if_nontrivial(&mut debug, self.span.inner); 860 debug.finish() 861 } 862} 863 864/// A word of Rust code, which may be a keyword or legal variable name. 865/// 866/// An identifier consists of at least one Unicode code point, the first of 867/// which has the XID_Start property and the rest of which have the XID_Continue 868/// property. 869/// 870/// - The empty string is not an identifier. Use `Option<Ident>`. 871/// - A lifetime is not an identifier. Use `syn::Lifetime` instead. 872/// 873/// An identifier constructed with `Ident::new` is permitted to be a Rust 874/// keyword, though parsing one through its [`Parse`] implementation rejects 875/// Rust keywords. Use `input.call(Ident::parse_any)` when parsing to match the 876/// behaviour of `Ident::new`. 877/// 878/// [`Parse`]: https://docs.rs/syn/2.0/syn/parse/trait.Parse.html 879/// 880/// # Examples 881/// 882/// A new ident can be created from a string using the `Ident::new` function. 883/// A span must be provided explicitly which governs the name resolution 884/// behavior of the resulting identifier. 885/// 886/// ``` 887/// use proc_macro2::{Ident, Span}; 888/// 889/// fn main() { 890/// let call_ident = Ident::new("calligraphy", Span::call_site()); 891/// 892/// println!("{}", call_ident); 893/// } 894/// ``` 895/// 896/// An ident can be interpolated into a token stream using the `quote!` macro. 897/// 898/// ``` 899/// use proc_macro2::{Ident, Span}; 900/// use quote::quote; 901/// 902/// fn main() { 903/// let ident = Ident::new("demo", Span::call_site()); 904/// 905/// // Create a variable binding whose name is this ident. 906/// let expanded = quote! { let #ident = 10; }; 907/// 908/// // Create a variable binding with a slightly different name. 909/// let temp_ident = Ident::new(&format!("new_{}", ident), Span::call_site()); 910/// let expanded = quote! { let #temp_ident = 10; }; 911/// } 912/// ``` 913/// 914/// A string representation of the ident is available through the `to_string()` 915/// method. 916/// 917/// ``` 918/// # use proc_macro2::{Ident, Span}; 919/// # 920/// # let ident = Ident::new("another_identifier", Span::call_site()); 921/// # 922/// // Examine the ident as a string. 923/// let ident_string = ident.to_string(); 924/// if ident_string.len() > 60 { 925/// println!("Very long identifier: {}", ident_string) 926/// } 927/// ``` 928#[derive(Clone)] 929pub struct Ident { 930 inner: imp::Ident, 931 _marker: ProcMacroAutoTraits, 932} 933 934impl Ident { 935 fn _new(inner: imp::Ident) -> Self { 936 Ident { 937 inner, 938 _marker: MARKER, 939 } 940 } 941 942 fn _new_fallback(inner: fallback::Ident) -> Self { 943 Ident { 944 inner: imp::Ident::from(inner), 945 _marker: MARKER, 946 } 947 } 948 949 /// Creates a new `Ident` with the given `string` as well as the specified 950 /// `span`. 951 /// 952 /// The `string` argument must be a valid identifier permitted by the 953 /// language, otherwise the function will panic. 954 /// 955 /// Note that `span`, currently in rustc, configures the hygiene information 956 /// for this identifier. 957 /// 958 /// As of this time `Span::call_site()` explicitly opts-in to "call-site" 959 /// hygiene meaning that identifiers created with this span will be resolved 960 /// as if they were written directly at the location of the macro call, and 961 /// other code at the macro call site will be able to refer to them as well. 962 /// 963 /// Later spans like `Span::def_site()` will allow to opt-in to 964 /// "definition-site" hygiene meaning that identifiers created with this 965 /// span will be resolved at the location of the macro definition and other 966 /// code at the macro call site will not be able to refer to them. 967 /// 968 /// Due to the current importance of hygiene this constructor, unlike other 969 /// tokens, requires a `Span` to be specified at construction. 970 /// 971 /// # Panics 972 /// 973 /// Panics if the input string is neither a keyword nor a legal variable 974 /// name. If you are not sure whether the string contains an identifier and 975 /// need to handle an error case, use 976 /// <a href="https://docs.rs/syn/2.0/syn/fn.parse_str.html"><code 977 /// style="padding-right:0;">syn::parse_str</code></a><code 978 /// style="padding-left:0;">::<Ident></code> 979 /// rather than `Ident::new`. 980 #[track_caller] 981 pub fn new(string: &str, span: Span) -> Self { 982 Ident::_new(imp::Ident::new_checked(string, span.inner)) 983 } 984 985 /// Same as `Ident::new`, but creates a raw identifier (`r#ident`). The 986 /// `string` argument must be a valid identifier permitted by the language 987 /// (including keywords, e.g. `fn`). Keywords which are usable in path 988 /// segments (e.g. `self`, `super`) are not supported, and will cause a 989 /// panic. 990 #[track_caller] 991 pub fn new_raw(string: &str, span: Span) -> Self { 992 Ident::_new(imp::Ident::new_raw_checked(string, span.inner)) 993 } 994 995 /// Returns the span of this `Ident`. 996 pub fn span(&self) -> Span { 997 Span::_new(self.inner.span()) 998 } 999 1000 /// Configures the span of this `Ident`, possibly changing its hygiene 1001 /// context. 1002 pub fn set_span(&mut self, span: Span) { 1003 self.inner.set_span(span.inner); 1004 } 1005} 1006 1007impl PartialEq for Ident { 1008 fn eq(&self, other: &Ident) -> bool { 1009 self.inner == other.inner 1010 } 1011} 1012 1013impl<T> PartialEq<T> for Ident 1014where 1015 T: ?Sized + AsRef<str>, 1016{ 1017 fn eq(&self, other: &T) -> bool { 1018 self.inner == other 1019 } 1020} 1021 1022impl Eq for Ident {} 1023 1024impl PartialOrd for Ident { 1025 fn partial_cmp(&self, other: &Ident) -> Option<Ordering> { 1026 Some(self.cmp(other)) 1027 } 1028} 1029 1030impl Ord for Ident { 1031 fn cmp(&self, other: &Ident) -> Ordering { 1032 self.to_string().cmp(&other.to_string()) 1033 } 1034} 1035 1036impl Hash for Ident { 1037 fn hash<H: Hasher>(&self, hasher: &mut H) { 1038 self.to_string().hash(hasher); 1039 } 1040} 1041 1042/// Prints the identifier as a string that should be losslessly convertible back 1043/// into the same identifier. 1044impl Display for Ident { 1045 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 1046 Display::fmt(&self.inner, f) 1047 } 1048} 1049 1050impl Debug for Ident { 1051 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 1052 Debug::fmt(&self.inner, f) 1053 } 1054} 1055 1056/// A literal string (`"hello"`), byte string (`b"hello"`), character (`'a'`), 1057/// byte character (`b'a'`), an integer or floating point number with or without 1058/// a suffix (`1`, `1u8`, `2.3`, `2.3f32`). 1059/// 1060/// Boolean literals like `true` and `false` do not belong here, they are 1061/// `Ident`s. 1062#[derive(Clone)] 1063pub struct Literal { 1064 inner: imp::Literal, 1065 _marker: ProcMacroAutoTraits, 1066} 1067 1068macro_rules! suffixed_int_literals { 1069 ($($name:ident => $kind:ident,)*) => ($( 1070 /// Creates a new suffixed integer literal with the specified value. 1071 /// 1072 /// This function will create an integer like `1u32` where the integer 1073 /// value specified is the first part of the token and the integral is 1074 /// also suffixed at the end. Literals created from negative numbers may 1075 /// not survive roundtrips through `TokenStream` or strings and may be 1076 /// broken into two tokens (`-` and positive literal). 1077 /// 1078 /// Literals created through this method have the `Span::call_site()` 1079 /// span by default, which can be configured with the `set_span` method 1080 /// below. 1081 pub fn $name(n: $kind) -> Literal { 1082 Literal::_new(imp::Literal::$name(n)) 1083 } 1084 )*) 1085} 1086 1087macro_rules! unsuffixed_int_literals { 1088 ($($name:ident => $kind:ident,)*) => ($( 1089 /// Creates a new unsuffixed integer literal with the specified value. 1090 /// 1091 /// This function will create an integer like `1` where the integer 1092 /// value specified is the first part of the token. No suffix is 1093 /// specified on this token, meaning that invocations like 1094 /// `Literal::i8_unsuffixed(1)` are equivalent to 1095 /// `Literal::u32_unsuffixed(1)`. Literals created from negative numbers 1096 /// may not survive roundtrips through `TokenStream` or strings and may 1097 /// be broken into two tokens (`-` and positive literal). 1098 /// 1099 /// Literals created through this method have the `Span::call_site()` 1100 /// span by default, which can be configured with the `set_span` method 1101 /// below. 1102 pub fn $name(n: $kind) -> Literal { 1103 Literal::_new(imp::Literal::$name(n)) 1104 } 1105 )*) 1106} 1107 1108impl Literal { 1109 fn _new(inner: imp::Literal) -> Self { 1110 Literal { 1111 inner, 1112 _marker: MARKER, 1113 } 1114 } 1115 1116 fn _new_fallback(inner: fallback::Literal) -> Self { 1117 Literal { 1118 inner: imp::Literal::from(inner), 1119 _marker: MARKER, 1120 } 1121 } 1122 1123 suffixed_int_literals! { 1124 u8_suffixed => u8, 1125 u16_suffixed => u16, 1126 u32_suffixed => u32, 1127 u64_suffixed => u64, 1128 u128_suffixed => u128, 1129 usize_suffixed => usize, 1130 i8_suffixed => i8, 1131 i16_suffixed => i16, 1132 i32_suffixed => i32, 1133 i64_suffixed => i64, 1134 i128_suffixed => i128, 1135 isize_suffixed => isize, 1136 } 1137 1138 unsuffixed_int_literals! { 1139 u8_unsuffixed => u8, 1140 u16_unsuffixed => u16, 1141 u32_unsuffixed => u32, 1142 u64_unsuffixed => u64, 1143 u128_unsuffixed => u128, 1144 usize_unsuffixed => usize, 1145 i8_unsuffixed => i8, 1146 i16_unsuffixed => i16, 1147 i32_unsuffixed => i32, 1148 i64_unsuffixed => i64, 1149 i128_unsuffixed => i128, 1150 isize_unsuffixed => isize, 1151 } 1152 1153 /// Creates a new unsuffixed floating-point literal. 1154 /// 1155 /// This constructor is similar to those like `Literal::i8_unsuffixed` where 1156 /// the float's value is emitted directly into the token but no suffix is 1157 /// used, so it may be inferred to be a `f64` later in the compiler. 1158 /// Literals created from negative numbers may not survive round-trips 1159 /// through `TokenStream` or strings and may be broken into two tokens (`-` 1160 /// and positive literal). 1161 /// 1162 /// # Panics 1163 /// 1164 /// This function requires that the specified float is finite, for example 1165 /// if it is infinity or NaN this function will panic. 1166 pub fn f64_unsuffixed(f: f64) -> Literal { 1167 assert!(f.is_finite()); 1168 Literal::_new(imp::Literal::f64_unsuffixed(f)) 1169 } 1170 1171 /// Creates a new suffixed floating-point literal. 1172 /// 1173 /// This constructor will create a literal like `1.0f64` where the value 1174 /// specified is the preceding part of the token and `f64` is the suffix of 1175 /// the token. This token will always be inferred to be an `f64` in the 1176 /// compiler. Literals created from negative numbers may not survive 1177 /// round-trips through `TokenStream` or strings and may be broken into two 1178 /// tokens (`-` and positive literal). 1179 /// 1180 /// # Panics 1181 /// 1182 /// This function requires that the specified float is finite, for example 1183 /// if it is infinity or NaN this function will panic. 1184 pub fn f64_suffixed(f: f64) -> Literal { 1185 assert!(f.is_finite()); 1186 Literal::_new(imp::Literal::f64_suffixed(f)) 1187 } 1188 1189 /// Creates a new unsuffixed floating-point literal. 1190 /// 1191 /// This constructor is similar to those like `Literal::i8_unsuffixed` where 1192 /// the float's value is emitted directly into the token but no suffix is 1193 /// used, so it may be inferred to be a `f64` later in the compiler. 1194 /// Literals created from negative numbers may not survive round-trips 1195 /// through `TokenStream` or strings and may be broken into two tokens (`-` 1196 /// and positive literal). 1197 /// 1198 /// # Panics 1199 /// 1200 /// This function requires that the specified float is finite, for example 1201 /// if it is infinity or NaN this function will panic. 1202 pub fn f32_unsuffixed(f: f32) -> Literal { 1203 assert!(f.is_finite()); 1204 Literal::_new(imp::Literal::f32_unsuffixed(f)) 1205 } 1206 1207 /// Creates a new suffixed floating-point literal. 1208 /// 1209 /// This constructor will create a literal like `1.0f32` where the value 1210 /// specified is the preceding part of the token and `f32` is the suffix of 1211 /// the token. This token will always be inferred to be an `f32` in the 1212 /// compiler. Literals created from negative numbers may not survive 1213 /// round-trips through `TokenStream` or strings and may be broken into two 1214 /// tokens (`-` and positive literal). 1215 /// 1216 /// # Panics 1217 /// 1218 /// This function requires that the specified float is finite, for example 1219 /// if it is infinity or NaN this function will panic. 1220 pub fn f32_suffixed(f: f32) -> Literal { 1221 assert!(f.is_finite()); 1222 Literal::_new(imp::Literal::f32_suffixed(f)) 1223 } 1224 1225 /// String literal. 1226 pub fn string(string: &str) -> Literal { 1227 Literal::_new(imp::Literal::string(string)) 1228 } 1229 1230 /// Character literal. 1231 pub fn character(ch: char) -> Literal { 1232 Literal::_new(imp::Literal::character(ch)) 1233 } 1234 1235 /// Byte character literal. 1236 pub fn byte_character(byte: u8) -> Literal { 1237 Literal::_new(imp::Literal::byte_character(byte)) 1238 } 1239 1240 /// Byte string literal. 1241 pub fn byte_string(bytes: &[u8]) -> Literal { 1242 Literal::_new(imp::Literal::byte_string(bytes)) 1243 } 1244 1245 /// C string literal. 1246 pub fn c_string(string: &CStr) -> Literal { 1247 Literal::_new(imp::Literal::c_string(string)) 1248 } 1249 1250 /// Returns the span encompassing this literal. 1251 pub fn span(&self) -> Span { 1252 Span::_new(self.inner.span()) 1253 } 1254 1255 /// Configures the span associated for this literal. 1256 pub fn set_span(&mut self, span: Span) { 1257 self.inner.set_span(span.inner); 1258 } 1259 1260 /// Returns a `Span` that is a subset of `self.span()` containing only 1261 /// the source bytes in range `range`. Returns `None` if the would-be 1262 /// trimmed span is outside the bounds of `self`. 1263 /// 1264 /// Warning: the underlying [`proc_macro::Literal::subspan`] method is 1265 /// nightly-only. When called from within a procedural macro not using a 1266 /// nightly compiler, this method will always return `None`. 1267 pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> { 1268 self.inner.subspan(range).map(Span::_new) 1269 } 1270 1271 // Intended for the `quote!` macro to use when constructing a proc-macro2 1272 // token out of a macro_rules $:literal token, which is already known to be 1273 // a valid literal. This avoids reparsing/validating the literal's string 1274 // representation. This is not public API other than for quote. 1275 #[doc(hidden)] 1276 pub unsafe fn from_str_unchecked(repr: &str) -> Self { 1277 Literal::_new(unsafe { imp::Literal::from_str_unchecked(repr) }) 1278 } 1279} 1280 1281impl FromStr for Literal { 1282 type Err = LexError; 1283 1284 fn from_str(repr: &str) -> Result<Self, LexError> { 1285 match imp::Literal::from_str_checked(repr) { 1286 Ok(lit) => Ok(Literal::_new(lit)), 1287 Err(lex) => Err(LexError { 1288 inner: lex, 1289 _marker: MARKER, 1290 }), 1291 } 1292 } 1293} 1294 1295impl Debug for Literal { 1296 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 1297 Debug::fmt(&self.inner, f) 1298 } 1299} 1300 1301impl Display for Literal { 1302 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 1303 Display::fmt(&self.inner, f) 1304 } 1305} 1306 1307/// Public implementation details for the `TokenStream` type, such as iterators. 1308pub mod token_stream { 1309 use crate::marker::{ProcMacroAutoTraits, MARKER}; 1310 use crate::{imp, TokenTree}; 1311 use core::fmt::{self, Debug}; 1312 1313 pub use crate::TokenStream; 1314 1315 /// An iterator over `TokenStream`'s `TokenTree`s. 1316 /// 1317 /// The iteration is "shallow", e.g. the iterator doesn't recurse into 1318 /// delimited groups, and returns whole groups as token trees. 1319 #[derive(Clone)] 1320 pub struct IntoIter { 1321 inner: imp::TokenTreeIter, 1322 _marker: ProcMacroAutoTraits, 1323 } 1324 1325 impl Iterator for IntoIter { 1326 type Item = TokenTree; 1327 1328 fn next(&mut self) -> Option<TokenTree> { 1329 self.inner.next() 1330 } 1331 1332 fn size_hint(&self) -> (usize, Option<usize>) { 1333 self.inner.size_hint() 1334 } 1335 } 1336 1337 impl Debug for IntoIter { 1338 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 1339 f.write_str("TokenStream ")?; 1340 f.debug_list().entries(self.clone()).finish() 1341 } 1342 } 1343 1344 impl IntoIterator for TokenStream { 1345 type Item = TokenTree; 1346 type IntoIter = IntoIter; 1347 1348 fn into_iter(self) -> IntoIter { 1349 IntoIter { 1350 inner: self.inner.into_iter(), 1351 _marker: MARKER, 1352 } 1353 } 1354 } 1355}
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