1//! [![github]](https://github.com/dtolnay/proc-macro2) [![crates-io]](https://crates.io/crates/proc-macro2) [![docs-rs]](crate)
2//!
3//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
4//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
5//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs
6//!
7//! <br>
8//!
9//! A wrapper around the procedural macro API of the compiler's [`proc_macro`]
10//! crate. This library serves two purposes:
11//!
12//! [`proc_macro`]: https://doc.rust-lang.org/proc_macro/
13//!
14//! - **Bring proc-macro-like functionality to other contexts like build.rs and
15//! main.rs.** Types from `proc_macro` are entirely specific to procedural
16//! macros and cannot ever exist in code outside of a procedural macro.
17//! Meanwhile `proc_macro2` types may exist anywhere including non-macro code.
18//! By developing foundational libraries like [syn] and [quote] against
19//! `proc_macro2` rather than `proc_macro`, the procedural macro ecosystem
20//! becomes easily applicable to many other use cases and we avoid
21//! reimplementing non-macro equivalents of those libraries.
22//!
23//! - **Make procedural macros unit testable.** As a consequence of being
24//! specific to procedural macros, nothing that uses `proc_macro` can be
25//! executed from a unit test. In order for helper libraries or components of
26//! a macro to be testable in isolation, they must be implemented using
27//! `proc_macro2`.
28//!
29//! [syn]: https://github.com/dtolnay/syn
30//! [quote]: https://github.com/dtolnay/quote
31//!
32//! # Usage
33//!
34//! The skeleton of a typical procedural macro typically looks like this:
35//!
36//! ```
37//! extern crate proc_macro;
38//!
39//! # const IGNORE: &str = stringify! {
40//! #[proc_macro_derive(MyDerive)]
41//! # };
42//! # #[cfg(wrap_proc_macro)]
43//! pub fn my_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
44//! let input = proc_macro2::TokenStream::from(input);
45//!
46//! let output: proc_macro2::TokenStream = {
47//! /* transform input */
48//! # input
49//! };
50//!
51//! proc_macro::TokenStream::from(output)
52//! }
53//! ```
54//!
55//! If parsing with [Syn], you'll use [`parse_macro_input!`] instead to
56//! propagate parse errors correctly back to the compiler when parsing fails.
57//!
58//! [`parse_macro_input!`]: https://docs.rs/syn/2.0/syn/macro.parse_macro_input.html
59//!
60//! # Unstable features
61//!
62//! The default feature set of proc-macro2 tracks the most recent stable
63//! compiler API. Functionality in `proc_macro` that is not yet stable is not
64//! exposed by proc-macro2 by default.
65//!
66//! To opt into the additional APIs available in the most recent nightly
67//! compiler, the `procmacro2_semver_exempt` config flag must be passed to
68//! rustc. We will polyfill those nightly-only APIs back to Rust 1.56.0. As
69//! these are unstable APIs that track the nightly compiler, minor versions of
70//! proc-macro2 may make breaking changes to them at any time.
71//!
72//! ```sh
73//! RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo build
74//! ```
75//!
76//! Note that this must not only be done for your crate, but for any crate that
77//! depends on your crate. This infectious nature is intentional, as it serves
78//! as a reminder that you are outside of the normal semver guarantees.
79//!
80//! Semver exempt methods are marked as such in the proc-macro2 documentation.
81//!
82//! # Thread-Safety
83//!
84//! Most types in this crate are `!Sync` because the underlying compiler
85//! types make use of thread-local memory, meaning they cannot be accessed from
86//! a different thread.
87
88// Proc-macro2 types in rustdoc of other crates get linked to here.
89#![doc(html_root_url = "https://docs.rs/proc-macro2/1.0.93")]
90#![cfg_attr(any(proc_macro_span, super_unstable), feature(proc_macro_span))]
91#![cfg_attr(super_unstable, feature(proc_macro_def_site))]
92#![cfg_attr(docsrs, feature(doc_cfg))]
93#![deny(unsafe_op_in_unsafe_fn)]
94#![allow(
95 clippy::cast_lossless,
96 clippy::cast_possible_truncation,
97 clippy::checked_conversions,
98 clippy::doc_markdown,
99 clippy::incompatible_msrv,
100 clippy::items_after_statements,
101 clippy::iter_without_into_iter,
102 clippy::let_underscore_untyped,
103 clippy::manual_assert,
104 clippy::manual_range_contains,
105 clippy::missing_panics_doc,
106 clippy::missing_safety_doc,
107 clippy::must_use_candidate,
108 clippy::needless_doctest_main,
109 clippy::needless_lifetimes,
110 clippy::new_without_default,
111 clippy::return_self_not_must_use,
112 clippy::shadow_unrelated,
113 clippy::trivially_copy_pass_by_ref,
114 clippy::unnecessary_wraps,
115 clippy::unused_self,
116 clippy::used_underscore_binding,
117 clippy::vec_init_then_push
118)]
119
120#[cfg(all(procmacro2_semver_exempt, wrap_proc_macro, not(super_unstable)))]
121compile_error! {"\
122 Something is not right. If you've tried to turn on \
123 procmacro2_semver_exempt, you need to ensure that it \
124 is turned on for the compilation of the proc-macro2 \
125 build script as well.
126"}
127
128#[cfg(all(
129 procmacro2_nightly_testing,
130 feature = "proc-macro",
131 not(proc_macro_span)
132))]
133compile_error! {"\
134 Build script probe failed to compile.
135"}
136
137extern crate alloc;
138
139#[cfg(feature = "proc-macro")]
140extern crate proc_macro;
141
142mod marker;
143mod parse;
144mod rcvec;
145
146#[cfg(wrap_proc_macro)]
147mod detection;
148
149// Public for proc_macro2::fallback::force() and unforce(), but those are quite
150// a niche use case so we omit it from rustdoc.
151#[doc(hidden)]
152pub mod fallback;
153
154pub mod extra;
155
156#[cfg(not(wrap_proc_macro))]
157use crate::fallback as imp;
158#[path = "wrapper.rs"]
159#[cfg(wrap_proc_macro)]
160mod imp;
161
162#[cfg(span_locations)]
163mod location;
164
165use crate::extra::DelimSpan;
166use crate::marker::{ProcMacroAutoTraits, MARKER};
167use core::cmp::Ordering;
168use core::fmt::{self, Debug, Display};
169use core::hash::{Hash, Hasher};
170#[cfg(span_locations)]
171use core::ops::Range;
172use core::ops::RangeBounds;
173use core::str::FromStr;
174use std::error::Error;
175use std::ffi::CStr;
176#[cfg(procmacro2_semver_exempt)]
177use std::path::PathBuf;
178
179#[cfg(span_locations)]
180#[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
181pub use crate::location::LineColumn;
182
183/// An abstract stream of tokens, or more concretely a sequence of token trees.
184///
185/// This type provides interfaces for iterating over token trees and for
186/// collecting token trees into one stream.
187///
188/// Token stream is both the input and output of `#[proc_macro]`,
189/// `#[proc_macro_attribute]` and `#[proc_macro_derive]` definitions.
190#[derive(Clone)]
191pub struct TokenStream {
192 inner: imp::TokenStream,
193 _marker: ProcMacroAutoTraits,
194}
195
196/// Error returned from `TokenStream::from_str`.
197pub struct LexError {
198 inner: imp::LexError,
199 _marker: ProcMacroAutoTraits,
200}
201
202impl TokenStream {
203 fn _new(inner: imp::TokenStream) -> Self {
204 TokenStream {
205 inner,
206 _marker: MARKER,
207 }
208 }
209
210 fn _new_fallback(inner: fallback::TokenStream) -> Self {
211 TokenStream {
212 inner: imp::TokenStream::from(inner),
213 _marker: MARKER,
214 }
215 }
216
217 /// Returns an empty `TokenStream` containing no token trees.
218 pub fn new() -> Self {
219 TokenStream::_new(imp::TokenStream::new())
220 }
221
222 /// Checks if this `TokenStream` is empty.
223 pub fn is_empty(&self) -> bool {
224 self.inner.is_empty()
225 }
226}
227
228/// `TokenStream::default()` returns an empty stream,
229/// i.e. this is equivalent with `TokenStream::new()`.
230impl Default for TokenStream {
231 fn default() -> Self {
232 TokenStream::new()
233 }
234}
235
236/// Attempts to break the string into tokens and parse those tokens into a token
237/// stream.
238///
239/// May fail for a number of reasons, for example, if the string contains
240/// unbalanced delimiters or characters not existing in the language.
241///
242/// NOTE: Some errors may cause panics instead of returning `LexError`. We
243/// reserve the right to change these errors into `LexError`s later.
244impl FromStr for TokenStream {
245 type Err = LexError;
246
247 fn from_str(src: &str) -> Result<TokenStream, LexError> {
248 match imp::TokenStream::from_str_checked(src) {
249 Ok(tokens: TokenStream) => Ok(TokenStream::_new(inner:tokens)),
250 Err(lex: LexError) => Err(LexError {
251 inner: lex,
252 _marker: MARKER,
253 }),
254 }
255 }
256}
257
258#[cfg(feature = "proc-macro")]
259#[cfg_attr(docsrs, doc(cfg(feature = "proc-macro")))]
260impl From<proc_macro::TokenStream> for TokenStream {
261 fn from(inner: proc_macro::TokenStream) -> Self {
262 TokenStream::_new(inner:imp::TokenStream::from(inner))
263 }
264}
265
266#[cfg(feature = "proc-macro")]
267#[cfg_attr(docsrs, doc(cfg(feature = "proc-macro")))]
268impl From<TokenStream> for proc_macro::TokenStream {
269 fn from(inner: TokenStream) -> Self {
270 proc_macro::TokenStream::from(inner.inner)
271 }
272}
273
274impl From<TokenTree> for TokenStream {
275 fn from(token: TokenTree) -> Self {
276 TokenStream::_new(inner:imp::TokenStream::from(token))
277 }
278}
279
280impl Extend<TokenTree> for TokenStream {
281 fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I) {
282 self.inner.extend(iter:streams);
283 }
284}
285
286impl Extend<TokenStream> for TokenStream {
287 fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
288 self.inner
289 .extend(iter:streams.into_iter().map(|stream: TokenStream| stream.inner));
290 }
291}
292
293/// Collects a number of token trees into a single stream.
294impl FromIterator<TokenTree> for TokenStream {
295 fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self {
296 TokenStream::_new(inner:streams.into_iter().collect())
297 }
298}
299impl FromIterator<TokenStream> for TokenStream {
300 fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
301 TokenStream::_new(inner:streams.into_iter().map(|i: TokenStream| i.inner).collect())
302 }
303}
304
305/// Prints the token stream as a string that is supposed to be losslessly
306/// convertible back into the same token stream (modulo spans), except for
307/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
308/// numeric literals.
309impl Display for TokenStream {
310 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
311 Display::fmt(&self.inner, f)
312 }
313}
314
315/// Prints token in a form convenient for debugging.
316impl Debug for TokenStream {
317 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
318 Debug::fmt(&self.inner, f)
319 }
320}
321
322impl LexError {
323 pub fn span(&self) -> Span {
324 Span::_new(self.inner.span())
325 }
326}
327
328impl Debug for LexError {
329 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
330 Debug::fmt(&self.inner, f)
331 }
332}
333
334impl Display for LexError {
335 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
336 Display::fmt(&self.inner, f)
337 }
338}
339
340impl Error for LexError {}
341
342/// The source file of a given `Span`.
343///
344/// This type is semver exempt and not exposed by default.
345#[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
346#[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
347#[derive(Clone, PartialEq, Eq)]
348pub struct SourceFile {
349 inner: imp::SourceFile,
350 _marker: ProcMacroAutoTraits,
351}
352
353#[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
354impl SourceFile {
355 fn _new(inner: imp::SourceFile) -> Self {
356 SourceFile {
357 inner,
358 _marker: MARKER,
359 }
360 }
361
362 /// Get the path to this source file.
363 ///
364 /// ### Note
365 ///
366 /// If the code span associated with this `SourceFile` was generated by an
367 /// external macro, this may not be an actual path on the filesystem. Use
368 /// [`is_real`] to check.
369 ///
370 /// Also note that even if `is_real` returns `true`, if
371 /// `--remap-path-prefix` was passed on the command line, the path as given
372 /// may not actually be valid.
373 ///
374 /// [`is_real`]: #method.is_real
375 pub fn path(&self) -> PathBuf {
376 self.inner.path()
377 }
378
379 /// Returns `true` if this source file is a real source file, and not
380 /// generated by an external macro's expansion.
381 pub fn is_real(&self) -> bool {
382 self.inner.is_real()
383 }
384}
385
386#[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
387impl Debug for SourceFile {
388 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
389 Debug::fmt(&self.inner, f)
390 }
391}
392
393/// A region of source code, along with macro expansion information.
394#[derive(Copy, Clone)]
395pub struct Span {
396 inner: imp::Span,
397 _marker: ProcMacroAutoTraits,
398}
399
400impl Span {
401 fn _new(inner: imp::Span) -> Self {
402 Span {
403 inner,
404 _marker: MARKER,
405 }
406 }
407
408 fn _new_fallback(inner: fallback::Span) -> Self {
409 Span {
410 inner: imp::Span::from(inner),
411 _marker: MARKER,
412 }
413 }
414
415 /// The span of the invocation of the current procedural macro.
416 ///
417 /// Identifiers created with this span will be resolved as if they were
418 /// written directly at the macro call location (call-site hygiene) and
419 /// other code at the macro call site will be able to refer to them as well.
420 pub fn call_site() -> Self {
421 Span::_new(imp::Span::call_site())
422 }
423
424 /// The span located at the invocation of the procedural macro, but with
425 /// local variables, labels, and `$crate` resolved at the definition site
426 /// of the macro. This is the same hygiene behavior as `macro_rules`.
427 pub fn mixed_site() -> Self {
428 Span::_new(imp::Span::mixed_site())
429 }
430
431 /// A span that resolves at the macro definition site.
432 ///
433 /// This method is semver exempt and not exposed by default.
434 #[cfg(procmacro2_semver_exempt)]
435 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
436 pub fn def_site() -> Self {
437 Span::_new(imp::Span::def_site())
438 }
439
440 /// Creates a new span with the same line/column information as `self` but
441 /// that resolves symbols as though it were at `other`.
442 pub fn resolved_at(&self, other: Span) -> Span {
443 Span::_new(self.inner.resolved_at(other.inner))
444 }
445
446 /// Creates a new span with the same name resolution behavior as `self` but
447 /// with the line/column information of `other`.
448 pub fn located_at(&self, other: Span) -> Span {
449 Span::_new(self.inner.located_at(other.inner))
450 }
451
452 /// Convert `proc_macro2::Span` to `proc_macro::Span`.
453 ///
454 /// This method is available when building with a nightly compiler, or when
455 /// building with rustc 1.29+ *without* semver exempt features.
456 ///
457 /// # Panics
458 ///
459 /// Panics if called from outside of a procedural macro. Unlike
460 /// `proc_macro2::Span`, the `proc_macro::Span` type can only exist within
461 /// the context of a procedural macro invocation.
462 #[cfg(wrap_proc_macro)]
463 pub fn unwrap(self) -> proc_macro::Span {
464 self.inner.unwrap()
465 }
466
467 // Soft deprecated. Please use Span::unwrap.
468 #[cfg(wrap_proc_macro)]
469 #[doc(hidden)]
470 pub fn unstable(self) -> proc_macro::Span {
471 self.unwrap()
472 }
473
474 /// The original source file into which this span points.
475 ///
476 /// This method is semver exempt and not exposed by default.
477 #[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
478 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
479 pub fn source_file(&self) -> SourceFile {
480 SourceFile::_new(self.inner.source_file())
481 }
482
483 /// Returns the span's byte position range in the source file.
484 ///
485 /// This method requires the `"span-locations"` feature to be enabled.
486 ///
487 /// When executing in a procedural macro context, the returned range is only
488 /// accurate if compiled with a nightly toolchain. The stable toolchain does
489 /// not have this information available. When executing outside of a
490 /// procedural macro, such as main.rs or build.rs, the byte range is always
491 /// accurate regardless of toolchain.
492 #[cfg(span_locations)]
493 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
494 pub fn byte_range(&self) -> Range<usize> {
495 self.inner.byte_range()
496 }
497
498 /// Get the starting line/column in the source file for this span.
499 ///
500 /// This method requires the `"span-locations"` feature to be enabled.
501 ///
502 /// When executing in a procedural macro context, the returned line/column
503 /// are only meaningful if compiled with a nightly toolchain. The stable
504 /// toolchain does not have this information available. When executing
505 /// outside of a procedural macro, such as main.rs or build.rs, the
506 /// line/column are always meaningful regardless of toolchain.
507 #[cfg(span_locations)]
508 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
509 pub fn start(&self) -> LineColumn {
510 self.inner.start()
511 }
512
513 /// Get the ending line/column in the source file for this span.
514 ///
515 /// This method requires the `"span-locations"` feature to be enabled.
516 ///
517 /// When executing in a procedural macro context, the returned line/column
518 /// are only meaningful if compiled with a nightly toolchain. The stable
519 /// toolchain does not have this information available. When executing
520 /// outside of a procedural macro, such as main.rs or build.rs, the
521 /// line/column are always meaningful regardless of toolchain.
522 #[cfg(span_locations)]
523 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
524 pub fn end(&self) -> LineColumn {
525 self.inner.end()
526 }
527
528 /// Create a new span encompassing `self` and `other`.
529 ///
530 /// Returns `None` if `self` and `other` are from different files.
531 ///
532 /// Warning: the underlying [`proc_macro::Span::join`] method is
533 /// nightly-only. When called from within a procedural macro not using a
534 /// nightly compiler, this method will always return `None`.
535 ///
536 /// [`proc_macro::Span::join`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.join
537 pub fn join(&self, other: Span) -> Option<Span> {
538 self.inner.join(other.inner).map(Span::_new)
539 }
540
541 /// Compares two spans to see if they're equal.
542 ///
543 /// This method is semver exempt and not exposed by default.
544 #[cfg(procmacro2_semver_exempt)]
545 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
546 pub fn eq(&self, other: &Span) -> bool {
547 self.inner.eq(&other.inner)
548 }
549
550 /// Returns the source text behind a span. This preserves the original
551 /// source code, including spaces and comments. It only returns a result if
552 /// the span corresponds to real source code.
553 ///
554 /// Note: The observable result of a macro should only rely on the tokens
555 /// and not on this source text. The result of this function is a best
556 /// effort to be used for diagnostics only.
557 pub fn source_text(&self) -> Option<String> {
558 self.inner.source_text()
559 }
560}
561
562/// Prints a span in a form convenient for debugging.
563impl Debug for Span {
564 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
565 Debug::fmt(&self.inner, f)
566 }
567}
568
569/// A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`).
570#[derive(Clone)]
571pub enum TokenTree {
572 /// A token stream surrounded by bracket delimiters.
573 Group(Group),
574 /// An identifier.
575 Ident(Ident),
576 /// A single punctuation character (`+`, `,`, `$`, etc.).
577 Punct(Punct),
578 /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
579 Literal(Literal),
580}
581
582impl TokenTree {
583 /// Returns the span of this tree, delegating to the `span` method of
584 /// the contained token or a delimited stream.
585 pub fn span(&self) -> Span {
586 match self {
587 TokenTree::Group(t) => t.span(),
588 TokenTree::Ident(t) => t.span(),
589 TokenTree::Punct(t) => t.span(),
590 TokenTree::Literal(t) => t.span(),
591 }
592 }
593
594 /// Configures the span for *only this token*.
595 ///
596 /// Note that if this token is a `Group` then this method will not configure
597 /// the span of each of the internal tokens, this will simply delegate to
598 /// the `set_span` method of each variant.
599 pub fn set_span(&mut self, span: Span) {
600 match self {
601 TokenTree::Group(t) => t.set_span(span),
602 TokenTree::Ident(t) => t.set_span(span),
603 TokenTree::Punct(t) => t.set_span(span),
604 TokenTree::Literal(t) => t.set_span(span),
605 }
606 }
607}
608
609impl From<Group> for TokenTree {
610 fn from(g: Group) -> Self {
611 TokenTree::Group(g)
612 }
613}
614
615impl From<Ident> for TokenTree {
616 fn from(g: Ident) -> Self {
617 TokenTree::Ident(g)
618 }
619}
620
621impl From<Punct> for TokenTree {
622 fn from(g: Punct) -> Self {
623 TokenTree::Punct(g)
624 }
625}
626
627impl From<Literal> for TokenTree {
628 fn from(g: Literal) -> Self {
629 TokenTree::Literal(g)
630 }
631}
632
633/// Prints the token tree as a string that is supposed to be losslessly
634/// convertible back into the same token tree (modulo spans), except for
635/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
636/// numeric literals.
637impl Display for TokenTree {
638 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
639 match self {
640 TokenTree::Group(t: &Group) => Display::fmt(self:t, f),
641 TokenTree::Ident(t: &Ident) => Display::fmt(self:t, f),
642 TokenTree::Punct(t: &Punct) => Display::fmt(self:t, f),
643 TokenTree::Literal(t: &Literal) => Display::fmt(self:t, f),
644 }
645 }
646}
647
648/// Prints token tree in a form convenient for debugging.
649impl Debug for TokenTree {
650 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
651 // Each of these has the name in the struct type in the derived debug,
652 // so don't bother with an extra layer of indirection
653 match self {
654 TokenTree::Group(t: &Group) => Debug::fmt(self:t, f),
655 TokenTree::Ident(t: &Ident) => {
656 let mut debug: DebugStruct<'_, '_> = f.debug_struct(name:"Ident");
657 debug.field(name:"sym", &format_args!("{}", t));
658 imp::debug_span_field_if_nontrivial(&mut debug, span:t.span().inner);
659 debug.finish()
660 }
661 TokenTree::Punct(t: &Punct) => Debug::fmt(self:t, f),
662 TokenTree::Literal(t: &Literal) => Debug::fmt(self:t, f),
663 }
664 }
665}
666
667/// A delimited token stream.
668///
669/// A `Group` internally contains a `TokenStream` which is surrounded by
670/// `Delimiter`s.
671#[derive(Clone)]
672pub struct Group {
673 inner: imp::Group,
674}
675
676/// Describes how a sequence of token trees is delimited.
677#[derive(Copy, Clone, Debug, Eq, PartialEq)]
678pub enum Delimiter {
679 /// `( ... )`
680 Parenthesis,
681 /// `{ ... }`
682 Brace,
683 /// `[ ... ]`
684 Bracket,
685 /// `∅ ... ∅`
686 ///
687 /// An invisible delimiter, that may, for example, appear around tokens
688 /// coming from a "macro variable" `$var`. It is important to preserve
689 /// operator priorities in cases like `$var * 3` where `$var` is `1 + 2`.
690 /// Invisible delimiters may not survive roundtrip of a token stream through
691 /// a string.
692 ///
693 /// <div class="warning">
694 ///
695 /// Note: rustc currently can ignore the grouping of tokens delimited by `None` in the output
696 /// of a proc_macro. Only `None`-delimited groups created by a macro_rules macro in the input
697 /// of a proc_macro macro are preserved, and only in very specific circumstances.
698 /// Any `None`-delimited groups (re)created by a proc_macro will therefore not preserve
699 /// operator priorities as indicated above. The other `Delimiter` variants should be used
700 /// instead in this context. This is a rustc bug. For details, see
701 /// [rust-lang/rust#67062](https://github.com/rust-lang/rust/issues/67062).
702 ///
703 /// </div>
704 None,
705}
706
707impl Group {
708 fn _new(inner: imp::Group) -> Self {
709 Group { inner }
710 }
711
712 fn _new_fallback(inner: fallback::Group) -> Self {
713 Group {
714 inner: imp::Group::from(inner),
715 }
716 }
717
718 /// Creates a new `Group` with the given delimiter and token stream.
719 ///
720 /// This constructor will set the span for this group to
721 /// `Span::call_site()`. To change the span you can use the `set_span`
722 /// method below.
723 pub fn new(delimiter: Delimiter, stream: TokenStream) -> Self {
724 Group {
725 inner: imp::Group::new(delimiter, stream.inner),
726 }
727 }
728
729 /// Returns the punctuation used as the delimiter for this group: a set of
730 /// parentheses, square brackets, or curly braces.
731 pub fn delimiter(&self) -> Delimiter {
732 self.inner.delimiter()
733 }
734
735 /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
736 ///
737 /// Note that the returned token stream does not include the delimiter
738 /// returned above.
739 pub fn stream(&self) -> TokenStream {
740 TokenStream::_new(self.inner.stream())
741 }
742
743 /// Returns the span for the delimiters of this token stream, spanning the
744 /// entire `Group`.
745 ///
746 /// ```text
747 /// pub fn span(&self) -> Span {
748 /// ^^^^^^^
749 /// ```
750 pub fn span(&self) -> Span {
751 Span::_new(self.inner.span())
752 }
753
754 /// Returns the span pointing to the opening delimiter of this group.
755 ///
756 /// ```text
757 /// pub fn span_open(&self) -> Span {
758 /// ^
759 /// ```
760 pub fn span_open(&self) -> Span {
761 Span::_new(self.inner.span_open())
762 }
763
764 /// Returns the span pointing to the closing delimiter of this group.
765 ///
766 /// ```text
767 /// pub fn span_close(&self) -> Span {
768 /// ^
769 /// ```
770 pub fn span_close(&self) -> Span {
771 Span::_new(self.inner.span_close())
772 }
773
774 /// Returns an object that holds this group's `span_open()` and
775 /// `span_close()` together (in a more compact representation than holding
776 /// those 2 spans individually).
777 pub fn delim_span(&self) -> DelimSpan {
778 DelimSpan::new(&self.inner)
779 }
780
781 /// Configures the span for this `Group`'s delimiters, but not its internal
782 /// tokens.
783 ///
784 /// This method will **not** set the span of all the internal tokens spanned
785 /// by this group, but rather it will only set the span of the delimiter
786 /// tokens at the level of the `Group`.
787 pub fn set_span(&mut self, span: Span) {
788 self.inner.set_span(span.inner);
789 }
790}
791
792/// Prints the group as a string that should be losslessly convertible back
793/// into the same group (modulo spans), except for possibly `TokenTree::Group`s
794/// with `Delimiter::None` delimiters.
795impl Display for Group {
796 fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
797 Display::fmt(&self.inner, f:formatter)
798 }
799}
800
801impl Debug for Group {
802 fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
803 Debug::fmt(&self.inner, f:formatter)
804 }
805}
806
807/// A `Punct` is a single punctuation character like `+`, `-` or `#`.
808///
809/// Multicharacter operators like `+=` are represented as two instances of
810/// `Punct` with different forms of `Spacing` returned.
811#[derive(Clone)]
812pub struct Punct {
813 ch: char,
814 spacing: Spacing,
815 span: Span,
816}
817
818/// Whether a `Punct` is followed immediately by another `Punct` or followed by
819/// another token or whitespace.
820#[derive(Copy, Clone, Debug, Eq, PartialEq)]
821pub enum Spacing {
822 /// E.g. `+` is `Alone` in `+ =`, `+ident` or `+()`.
823 Alone,
824 /// E.g. `+` is `Joint` in `+=` or `'` is `Joint` in `'#`.
825 ///
826 /// Additionally, single quote `'` can join with identifiers to form
827 /// lifetimes `'ident`.
828 Joint,
829}
830
831impl Punct {
832 /// Creates a new `Punct` from the given character and spacing.
833 ///
834 /// The `ch` argument must be a valid punctuation character permitted by the
835 /// language, otherwise the function will panic.
836 ///
837 /// The returned `Punct` will have the default span of `Span::call_site()`
838 /// which can be further configured with the `set_span` method below.
839 pub fn new(ch: char, spacing: Spacing) -> Self {
840 if let '!' | '#' | '$' | '%' | '&' | '\'' | '*' | '+' | ',' | '-' | '.' | '/' | ':' | ';'
841 | '<' | '=' | '>' | '?' | '@' | '^' | '|' | '~' = ch
842 {
843 Punct {
844 ch,
845 spacing,
846 span: Span::call_site(),
847 }
848 } else {
849 panic!("unsupported proc macro punctuation character {:?}", ch);
850 }
851 }
852
853 /// Returns the value of this punctuation character as `char`.
854 pub fn as_char(&self) -> char {
855 self.ch
856 }
857
858 /// Returns the spacing of this punctuation character, indicating whether
859 /// it's immediately followed by another `Punct` in the token stream, so
860 /// they can potentially be combined into a multicharacter operator
861 /// (`Joint`), or it's followed by some other token or whitespace (`Alone`)
862 /// so the operator has certainly ended.
863 pub fn spacing(&self) -> Spacing {
864 self.spacing
865 }
866
867 /// Returns the span for this punctuation character.
868 pub fn span(&self) -> Span {
869 self.span
870 }
871
872 /// Configure the span for this punctuation character.
873 pub fn set_span(&mut self, span: Span) {
874 self.span = span;
875 }
876}
877
878/// Prints the punctuation character as a string that should be losslessly
879/// convertible back into the same character.
880impl Display for Punct {
881 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
882 Display::fmt(&self.ch, f)
883 }
884}
885
886impl Debug for Punct {
887 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
888 let mut debug: DebugStruct<'_, '_> = fmt.debug_struct(name:"Punct");
889 debug.field(name:"char", &self.ch);
890 debug.field(name:"spacing", &self.spacing);
891 imp::debug_span_field_if_nontrivial(&mut debug, self.span.inner);
892 debug.finish()
893 }
894}
895
896/// A word of Rust code, which may be a keyword or legal variable name.
897///
898/// An identifier consists of at least one Unicode code point, the first of
899/// which has the XID_Start property and the rest of which have the XID_Continue
900/// property.
901///
902/// - The empty string is not an identifier. Use `Option<Ident>`.
903/// - A lifetime is not an identifier. Use `syn::Lifetime` instead.
904///
905/// An identifier constructed with `Ident::new` is permitted to be a Rust
906/// keyword, though parsing one through its [`Parse`] implementation rejects
907/// Rust keywords. Use `input.call(Ident::parse_any)` when parsing to match the
908/// behaviour of `Ident::new`.
909///
910/// [`Parse`]: https://docs.rs/syn/2.0/syn/parse/trait.Parse.html
911///
912/// # Examples
913///
914/// A new ident can be created from a string using the `Ident::new` function.
915/// A span must be provided explicitly which governs the name resolution
916/// behavior of the resulting identifier.
917///
918/// ```
919/// use proc_macro2::{Ident, Span};
920///
921/// fn main() {
922/// let call_ident = Ident::new("calligraphy", Span::call_site());
923///
924/// println!("{}", call_ident);
925/// }
926/// ```
927///
928/// An ident can be interpolated into a token stream using the `quote!` macro.
929///
930/// ```
931/// use proc_macro2::{Ident, Span};
932/// use quote::quote;
933///
934/// fn main() {
935/// let ident = Ident::new("demo", Span::call_site());
936///
937/// // Create a variable binding whose name is this ident.
938/// let expanded = quote! { let #ident = 10; };
939///
940/// // Create a variable binding with a slightly different name.
941/// let temp_ident = Ident::new(&format!("new_{}", ident), Span::call_site());
942/// let expanded = quote! { let #temp_ident = 10; };
943/// }
944/// ```
945///
946/// A string representation of the ident is available through the `to_string()`
947/// method.
948///
949/// ```
950/// # use proc_macro2::{Ident, Span};
951/// #
952/// # let ident = Ident::new("another_identifier", Span::call_site());
953/// #
954/// // Examine the ident as a string.
955/// let ident_string = ident.to_string();
956/// if ident_string.len() > 60 {
957/// println!("Very long identifier: {}", ident_string)
958/// }
959/// ```
960#[derive(Clone)]
961pub struct Ident {
962 inner: imp::Ident,
963 _marker: ProcMacroAutoTraits,
964}
965
966impl Ident {
967 fn _new(inner: imp::Ident) -> Self {
968 Ident {
969 inner,
970 _marker: MARKER,
971 }
972 }
973
974 fn _new_fallback(inner: fallback::Ident) -> Self {
975 Ident {
976 inner: imp::Ident::from(inner),
977 _marker: MARKER,
978 }
979 }
980
981 /// Creates a new `Ident` with the given `string` as well as the specified
982 /// `span`.
983 ///
984 /// The `string` argument must be a valid identifier permitted by the
985 /// language, otherwise the function will panic.
986 ///
987 /// Note that `span`, currently in rustc, configures the hygiene information
988 /// for this identifier.
989 ///
990 /// As of this time `Span::call_site()` explicitly opts-in to "call-site"
991 /// hygiene meaning that identifiers created with this span will be resolved
992 /// as if they were written directly at the location of the macro call, and
993 /// other code at the macro call site will be able to refer to them as well.
994 ///
995 /// Later spans like `Span::def_site()` will allow to opt-in to
996 /// "definition-site" hygiene meaning that identifiers created with this
997 /// span will be resolved at the location of the macro definition and other
998 /// code at the macro call site will not be able to refer to them.
999 ///
1000 /// Due to the current importance of hygiene this constructor, unlike other
1001 /// tokens, requires a `Span` to be specified at construction.
1002 ///
1003 /// # Panics
1004 ///
1005 /// Panics if the input string is neither a keyword nor a legal variable
1006 /// name. If you are not sure whether the string contains an identifier and
1007 /// need to handle an error case, use
1008 /// <a href="https://docs.rs/syn/2.0/syn/fn.parse_str.html"><code
1009 /// style="padding-right:0;">syn::parse_str</code></a><code
1010 /// style="padding-left:0;">::&lt;Ident&gt;</code>
1011 /// rather than `Ident::new`.
1012 #[track_caller]
1013 pub fn new(string: &str, span: Span) -> Self {
1014 Ident::_new(imp::Ident::new_checked(string, span.inner))
1015 }
1016
1017 /// Same as `Ident::new`, but creates a raw identifier (`r#ident`). The
1018 /// `string` argument must be a valid identifier permitted by the language
1019 /// (including keywords, e.g. `fn`). Keywords which are usable in path
1020 /// segments (e.g. `self`, `super`) are not supported, and will cause a
1021 /// panic.
1022 #[track_caller]
1023 pub fn new_raw(string: &str, span: Span) -> Self {
1024 Ident::_new(imp::Ident::new_raw_checked(string, span.inner))
1025 }
1026
1027 /// Returns the span of this `Ident`.
1028 pub fn span(&self) -> Span {
1029 Span::_new(self.inner.span())
1030 }
1031
1032 /// Configures the span of this `Ident`, possibly changing its hygiene
1033 /// context.
1034 pub fn set_span(&mut self, span: Span) {
1035 self.inner.set_span(span.inner);
1036 }
1037}
1038
1039impl PartialEq for Ident {
1040 fn eq(&self, other: &Ident) -> bool {
1041 self.inner == other.inner
1042 }
1043}
1044
1045impl<T> PartialEq<T> for Ident
1046where
1047 T: ?Sized + AsRef<str>,
1048{
1049 fn eq(&self, other: &T) -> bool {
1050 self.inner == other
1051 }
1052}
1053
1054impl Eq for Ident {}
1055
1056impl PartialOrd for Ident {
1057 fn partial_cmp(&self, other: &Ident) -> Option<Ordering> {
1058 Some(self.cmp(other))
1059 }
1060}
1061
1062impl Ord for Ident {
1063 fn cmp(&self, other: &Ident) -> Ordering {
1064 self.to_string().cmp(&other.to_string())
1065 }
1066}
1067
1068impl Hash for Ident {
1069 fn hash<H: Hasher>(&self, hasher: &mut H) {
1070 self.to_string().hash(state:hasher);
1071 }
1072}
1073
1074/// Prints the identifier as a string that should be losslessly convertible back
1075/// into the same identifier.
1076impl Display for Ident {
1077 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1078 Display::fmt(&self.inner, f)
1079 }
1080}
1081
1082impl Debug for Ident {
1083 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1084 Debug::fmt(&self.inner, f)
1085 }
1086}
1087
1088/// A literal string (`"hello"`), byte string (`b"hello"`), character (`'a'`),
1089/// byte character (`b'a'`), an integer or floating point number with or without
1090/// a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
1091///
1092/// Boolean literals like `true` and `false` do not belong here, they are
1093/// `Ident`s.
1094#[derive(Clone)]
1095pub struct Literal {
1096 inner: imp::Literal,
1097 _marker: ProcMacroAutoTraits,
1098}
1099
1100macro_rules! suffixed_int_literals {
1101 ($($name:ident => $kind:ident,)*) => ($(
1102 /// Creates a new suffixed integer literal with the specified value.
1103 ///
1104 /// This function will create an integer like `1u32` where the integer
1105 /// value specified is the first part of the token and the integral is
1106 /// also suffixed at the end. Literals created from negative numbers may
1107 /// not survive roundtrips through `TokenStream` or strings and may be
1108 /// broken into two tokens (`-` and positive literal).
1109 ///
1110 /// Literals created through this method have the `Span::call_site()`
1111 /// span by default, which can be configured with the `set_span` method
1112 /// below.
1113 pub fn $name(n: $kind) -> Literal {
1114 Literal::_new(imp::Literal::$name(n))
1115 }
1116 )*)
1117}
1118
1119macro_rules! unsuffixed_int_literals {
1120 ($($name:ident => $kind:ident,)*) => ($(
1121 /// Creates a new unsuffixed integer literal with the specified value.
1122 ///
1123 /// This function will create an integer like `1` where the integer
1124 /// value specified is the first part of the token. No suffix is
1125 /// specified on this token, meaning that invocations like
1126 /// `Literal::i8_unsuffixed(1)` are equivalent to
1127 /// `Literal::u32_unsuffixed(1)`. Literals created from negative numbers
1128 /// may not survive roundtrips through `TokenStream` or strings and may
1129 /// be broken into two tokens (`-` and positive literal).
1130 ///
1131 /// Literals created through this method have the `Span::call_site()`
1132 /// span by default, which can be configured with the `set_span` method
1133 /// below.
1134 pub fn $name(n: $kind) -> Literal {
1135 Literal::_new(imp::Literal::$name(n))
1136 }
1137 )*)
1138}
1139
1140impl Literal {
1141 fn _new(inner: imp::Literal) -> Self {
1142 Literal {
1143 inner,
1144 _marker: MARKER,
1145 }
1146 }
1147
1148 fn _new_fallback(inner: fallback::Literal) -> Self {
1149 Literal {
1150 inner: imp::Literal::from(inner),
1151 _marker: MARKER,
1152 }
1153 }
1154
1155 suffixed_int_literals! {
1156 u8_suffixed => u8,
1157 u16_suffixed => u16,
1158 u32_suffixed => u32,
1159 u64_suffixed => u64,
1160 u128_suffixed => u128,
1161 usize_suffixed => usize,
1162 i8_suffixed => i8,
1163 i16_suffixed => i16,
1164 i32_suffixed => i32,
1165 i64_suffixed => i64,
1166 i128_suffixed => i128,
1167 isize_suffixed => isize,
1168 }
1169
1170 unsuffixed_int_literals! {
1171 u8_unsuffixed => u8,
1172 u16_unsuffixed => u16,
1173 u32_unsuffixed => u32,
1174 u64_unsuffixed => u64,
1175 u128_unsuffixed => u128,
1176 usize_unsuffixed => usize,
1177 i8_unsuffixed => i8,
1178 i16_unsuffixed => i16,
1179 i32_unsuffixed => i32,
1180 i64_unsuffixed => i64,
1181 i128_unsuffixed => i128,
1182 isize_unsuffixed => isize,
1183 }
1184
1185 /// Creates a new unsuffixed floating-point literal.
1186 ///
1187 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1188 /// the float's value is emitted directly into the token but no suffix is
1189 /// used, so it may be inferred to be a `f64` later in the compiler.
1190 /// Literals created from negative numbers may not survive round-trips
1191 /// through `TokenStream` or strings and may be broken into two tokens (`-`
1192 /// and positive literal).
1193 ///
1194 /// # Panics
1195 ///
1196 /// This function requires that the specified float is finite, for example
1197 /// if it is infinity or NaN this function will panic.
1198 pub fn f64_unsuffixed(f: f64) -> Literal {
1199 assert!(f.is_finite());
1200 Literal::_new(imp::Literal::f64_unsuffixed(f))
1201 }
1202
1203 /// Creates a new suffixed floating-point literal.
1204 ///
1205 /// This constructor will create a literal like `1.0f64` where the value
1206 /// specified is the preceding part of the token and `f64` is the suffix of
1207 /// the token. This token will always be inferred to be an `f64` in the
1208 /// compiler. Literals created from negative numbers may not survive
1209 /// round-trips through `TokenStream` or strings and may be broken into two
1210 /// tokens (`-` and positive literal).
1211 ///
1212 /// # Panics
1213 ///
1214 /// This function requires that the specified float is finite, for example
1215 /// if it is infinity or NaN this function will panic.
1216 pub fn f64_suffixed(f: f64) -> Literal {
1217 assert!(f.is_finite());
1218 Literal::_new(imp::Literal::f64_suffixed(f))
1219 }
1220
1221 /// Creates a new unsuffixed floating-point literal.
1222 ///
1223 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1224 /// the float's value is emitted directly into the token but no suffix is
1225 /// used, so it may be inferred to be a `f64` later in the compiler.
1226 /// Literals created from negative numbers may not survive round-trips
1227 /// through `TokenStream` or strings and may be broken into two tokens (`-`
1228 /// and positive literal).
1229 ///
1230 /// # Panics
1231 ///
1232 /// This function requires that the specified float is finite, for example
1233 /// if it is infinity or NaN this function will panic.
1234 pub fn f32_unsuffixed(f: f32) -> Literal {
1235 assert!(f.is_finite());
1236 Literal::_new(imp::Literal::f32_unsuffixed(f))
1237 }
1238
1239 /// Creates a new suffixed floating-point literal.
1240 ///
1241 /// This constructor will create a literal like `1.0f32` where the value
1242 /// specified is the preceding part of the token and `f32` is the suffix of
1243 /// the token. This token will always be inferred to be an `f32` in the
1244 /// compiler. Literals created from negative numbers may not survive
1245 /// round-trips through `TokenStream` or strings and may be broken into two
1246 /// tokens (`-` and positive literal).
1247 ///
1248 /// # Panics
1249 ///
1250 /// This function requires that the specified float is finite, for example
1251 /// if it is infinity or NaN this function will panic.
1252 pub fn f32_suffixed(f: f32) -> Literal {
1253 assert!(f.is_finite());
1254 Literal::_new(imp::Literal::f32_suffixed(f))
1255 }
1256
1257 /// String literal.
1258 pub fn string(string: &str) -> Literal {
1259 Literal::_new(imp::Literal::string(string))
1260 }
1261
1262 /// Character literal.
1263 pub fn character(ch: char) -> Literal {
1264 Literal::_new(imp::Literal::character(ch))
1265 }
1266
1267 /// Byte character literal.
1268 pub fn byte_character(byte: u8) -> Literal {
1269 Literal::_new(imp::Literal::byte_character(byte))
1270 }
1271
1272 /// Byte string literal.
1273 pub fn byte_string(bytes: &[u8]) -> Literal {
1274 Literal::_new(imp::Literal::byte_string(bytes))
1275 }
1276
1277 /// C string literal.
1278 pub fn c_string(string: &CStr) -> Literal {
1279 Literal::_new(imp::Literal::c_string(string))
1280 }
1281
1282 /// Returns the span encompassing this literal.
1283 pub fn span(&self) -> Span {
1284 Span::_new(self.inner.span())
1285 }
1286
1287 /// Configures the span associated for this literal.
1288 pub fn set_span(&mut self, span: Span) {
1289 self.inner.set_span(span.inner);
1290 }
1291
1292 /// Returns a `Span` that is a subset of `self.span()` containing only
1293 /// the source bytes in range `range`. Returns `None` if the would-be
1294 /// trimmed span is outside the bounds of `self`.
1295 ///
1296 /// Warning: the underlying [`proc_macro::Literal::subspan`] method is
1297 /// nightly-only. When called from within a procedural macro not using a
1298 /// nightly compiler, this method will always return `None`.
1299 ///
1300 /// [`proc_macro::Literal::subspan`]: https://doc.rust-lang.org/proc_macro/struct.Literal.html#method.subspan
1301 pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
1302 self.inner.subspan(range).map(Span::_new)
1303 }
1304
1305 // Intended for the `quote!` macro to use when constructing a proc-macro2
1306 // token out of a macro_rules $:literal token, which is already known to be
1307 // a valid literal. This avoids reparsing/validating the literal's string
1308 // representation. This is not public API other than for quote.
1309 #[doc(hidden)]
1310 pub unsafe fn from_str_unchecked(repr: &str) -> Self {
1311 Literal::_new(unsafe { imp::Literal::from_str_unchecked(repr) })
1312 }
1313}
1314
1315impl FromStr for Literal {
1316 type Err = LexError;
1317
1318 fn from_str(repr: &str) -> Result<Self, LexError> {
1319 match imp::Literal::from_str_checked(repr) {
1320 Ok(lit: Literal) => Ok(Literal::_new(inner:lit)),
1321 Err(lex: LexError) => Err(LexError {
1322 inner: lex,
1323 _marker: MARKER,
1324 }),
1325 }
1326 }
1327}
1328
1329impl Debug for Literal {
1330 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1331 Debug::fmt(&self.inner, f)
1332 }
1333}
1334
1335impl Display for Literal {
1336 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1337 Display::fmt(&self.inner, f)
1338 }
1339}
1340
1341/// Public implementation details for the `TokenStream` type, such as iterators.
1342pub mod token_stream {
1343 use crate::marker::{ProcMacroAutoTraits, MARKER};
1344 use crate::{imp, TokenTree};
1345 use core::fmt::{self, Debug};
1346
1347 pub use crate::TokenStream;
1348
1349 /// An iterator over `TokenStream`'s `TokenTree`s.
1350 ///
1351 /// The iteration is "shallow", e.g. the iterator doesn't recurse into
1352 /// delimited groups, and returns whole groups as token trees.
1353 #[derive(Clone)]
1354 pub struct IntoIter {
1355 inner: imp::TokenTreeIter,
1356 _marker: ProcMacroAutoTraits,
1357 }
1358
1359 impl Iterator for IntoIter {
1360 type Item = TokenTree;
1361
1362 fn next(&mut self) -> Option<TokenTree> {
1363 self.inner.next()
1364 }
1365
1366 fn size_hint(&self) -> (usize, Option<usize>) {
1367 self.inner.size_hint()
1368 }
1369 }
1370
1371 impl Debug for IntoIter {
1372 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1373 f.write_str("TokenStream ")?;
1374 f.debug_list().entries(self.clone()).finish()
1375 }
1376 }
1377
1378 impl IntoIterator for TokenStream {
1379 type Item = TokenTree;
1380 type IntoIter = IntoIter;
1381
1382 fn into_iter(self) -> IntoIter {
1383 IntoIter {
1384 inner: self.inner.into_iter(),
1385 _marker: MARKER,
1386 }
1387 }
1388 }
1389}
1390