safe_proc_macro2/lib.rs
1//! This is a fork of `safe_proc_macro2` with unsafe code removed.
2//! See the [rejected PR](https://github.com/alexcrichton/proc-macro2/pull/261).
3//! ----
4//!
5//! A wrapper around the procedural macro API of the compiler's [`proc_macro`]
6//! crate. This library serves two purposes:
7//!
8//! - **Bring proc-macro-like functionality to other contexts like build.rs and
9//! main.rs.** Types from `proc_macro` are entirely specific to procedural
10//! macros and cannot ever exist in code outside of a procedural macro.
11//! Meanwhile `proc_macro2` types may exist anywhere including non-macro code.
12//! By developing foundational libraries like [syn] and [quote] against
13//! `proc_macro2` rather than `proc_macro`, the procedural macro ecosystem
14//! becomes easily applicable to many other use cases and we avoid
15//! reimplementing non-macro equivalents of those libraries.
16//!
17//! - **Make procedural macros unit testable.** As a consequence of being
18//! specific to procedural macros, nothing that uses `proc_macro` can be
19//! executed from a unit test. In order for helper libraries or components of
20//! a macro to be testable in isolation, they must be implemented using
21//! `proc_macro2`.
22//!
23//! [syn]: https://github.com/dtolnay/syn
24//! [quote]: https://github.com/dtolnay/quote
25//!
26//! # Usage
27//!
28//! The skeleton of a typical procedural macro typically looks like this:
29//!
30//! ```
31//! extern crate proc_macro;
32//!
33//! # const IGNORE: &str = stringify! {
34//! #[proc_macro_derive(MyDerive)]
35//! # };
36//! # #[cfg(wrap_proc_macro)]
37//! pub fn my_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
38//! let input = safe_proc_macro2::TokenStream::from(input);
39//!
40//! let output: safe_proc_macro2::TokenStream = {
41//! /* transform input */
42//! # input
43//! };
44//!
45//! proc_macro::TokenStream::from(output)
46//! }
47//! ```
48//!
49//! If parsing with [Syn], you'll use [`parse_macro_input!`] instead to
50//! propagate parse errors correctly back to the compiler when parsing fails.
51//!
52//! [`parse_macro_input!`]: https://docs.rs/syn/2.0/syn/macro.parse_macro_input.html
53//!
54//! # Unstable features
55//!
56//! The default feature set of proc-macro2 tracks the most recent stable
57//! compiler API. Functionality in `proc_macro` that is not yet stable is not
58//! exposed by proc-macro2 by default.
59//!
60//! To opt into the additional APIs available in the most recent nightly
61//! compiler, the `procmacro2_semver_exempt` config flag must be passed to
62//! rustc. We will polyfill those nightly-only APIs back to Rust 1.56.0. As
63//! these are unstable APIs that track the nightly compiler, minor versions of
64//! proc-macro2 may make breaking changes to them at any time.
65//!
66//! ```sh
67//! RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo build
68//! ```
69//!
70//! Note that this must not only be done for your crate, but for any crate that
71//! depends on your crate. This infectious nature is intentional, as it serves
72//! as a reminder that you are outside of the normal semver guarantees.
73//!
74//! Semver exempt methods are marked as such in the proc-macro2 documentation.
75//!
76//! # Thread-Safety
77//!
78//! Most types in this crate are `!Sync` because the underlying compiler
79//! types make use of thread-local memory, meaning they cannot be accessed from
80//! a different thread.
81#![forbid(unsafe_code)]
82
83// Proc-macro2 types in rustdoc of other crates get linked to here.
84#![doc(html_root_url = "https://docs.rs/safe-proc-macro2/1.0.95")]
85#![cfg_attr(any(proc_macro_span, super_unstable), feature(proc_macro_span))]
86#![cfg_attr(super_unstable, feature(proc_macro_def_site))]
87#![cfg_attr(docsrs, feature(doc_cfg))]
88#![deny(unsafe_op_in_unsafe_fn)]
89#![allow(
90 clippy::cast_lossless,
91 clippy::cast_possible_truncation,
92 clippy::checked_conversions,
93 clippy::doc_markdown,
94 clippy::elidable_lifetime_names,
95 clippy::incompatible_msrv,
96 clippy::items_after_statements,
97 clippy::iter_without_into_iter,
98 clippy::let_underscore_untyped,
99 clippy::manual_assert,
100 clippy::manual_range_contains,
101 clippy::missing_panics_doc,
102 clippy::missing_safety_doc,
103 clippy::must_use_candidate,
104 clippy::needless_doctest_main,
105 clippy::needless_lifetimes,
106 clippy::new_without_default,
107 clippy::return_self_not_must_use,
108 clippy::shadow_unrelated,
109 clippy::trivially_copy_pass_by_ref,
110 clippy::unnecessary_wraps,
111 clippy::unused_self,
112 clippy::used_underscore_binding,
113 clippy::vec_init_then_push
114)]
115
116#[cfg(all(procmacro2_semver_exempt, wrap_proc_macro, not(super_unstable)))]
117compile_error! {"\
118 Something is not right. If you've tried to turn on \
119 procmacro2_semver_exempt, you need to ensure that it \
120 is turned on for the compilation of the proc-macro2 \
121 build script as well.
122"}
123
124#[cfg(all(
125 procmacro2_nightly_testing,
126 feature = "proc-macro",
127 not(proc_macro_span)
128))]
129compile_error! {"\
130 Build script probe failed to compile.
131"}
132
133extern crate alloc;
134
135#[cfg(feature = "proc-macro")]
136extern crate proc_macro;
137
138mod marker;
139mod parse;
140mod rcvec;
141
142#[cfg(wrap_proc_macro)]
143mod detection;
144
145// Public for safe_proc_macro2::fallback::force() and unforce(), but those are quite
146// a niche use case so we omit it from rustdoc.
147#[doc(hidden)]
148pub mod fallback;
149
150pub mod extra;
151
152#[cfg(not(wrap_proc_macro))]
153use crate::fallback as imp;
154#[path = "wrapper.rs"]
155#[cfg(wrap_proc_macro)]
156mod imp;
157
158#[cfg(span_locations)]
159mod location;
160
161use crate::extra::DelimSpan;
162use crate::marker::{ProcMacroAutoTraits, MARKER};
163use core::cmp::Ordering;
164use core::fmt::{self, Debug, Display};
165use core::hash::{Hash, Hasher};
166#[cfg(span_locations)]
167use core::ops::Range;
168use core::ops::RangeBounds;
169use core::str::FromStr;
170use std::error::Error;
171use std::ffi::CStr;
172#[cfg(procmacro2_semver_exempt)]
173use std::path::PathBuf;
174
175#[cfg(span_locations)]
176#[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
177pub use crate::location::LineColumn;
178
179/// An abstract stream of tokens, or more concretely a sequence of token trees.
180///
181/// This type provides interfaces for iterating over token trees and for
182/// collecting token trees into one stream.
183///
184/// Token stream is both the input and output of `#[proc_macro]`,
185/// `#[proc_macro_attribute]` and `#[proc_macro_derive]` definitions.
186#[derive(Clone)]
187pub struct TokenStream {
188 inner: imp::TokenStream,
189 _marker: ProcMacroAutoTraits,
190}
191
192/// Error returned from `TokenStream::from_str`.
193pub struct LexError {
194 inner: imp::LexError,
195 _marker: ProcMacroAutoTraits,
196}
197
198impl TokenStream {
199 fn _new(inner: imp::TokenStream) -> Self {
200 TokenStream {
201 inner,
202 _marker: MARKER,
203 }
204 }
205
206 fn _new_fallback(inner: fallback::TokenStream) -> Self {
207 TokenStream {
208 inner: imp::TokenStream::from(inner),
209 _marker: MARKER,
210 }
211 }
212
213 /// Returns an empty `TokenStream` containing no token trees.
214 pub fn new() -> Self {
215 TokenStream::_new(imp::TokenStream::new())
216 }
217
218 /// Checks if this `TokenStream` is empty.
219 pub fn is_empty(&self) -> bool {
220 self.inner.is_empty()
221 }
222}
223
224/// `TokenStream::default()` returns an empty stream,
225/// i.e. this is equivalent with `TokenStream::new()`.
226impl Default for TokenStream {
227 fn default() -> Self {
228 TokenStream::new()
229 }
230}
231
232/// Attempts to break the string into tokens and parse those tokens into a token
233/// stream.
234///
235/// May fail for a number of reasons, for example, if the string contains
236/// unbalanced delimiters or characters not existing in the language.
237///
238/// NOTE: Some errors may cause panics instead of returning `LexError`. We
239/// reserve the right to change these errors into `LexError`s later.
240impl FromStr for TokenStream {
241 type Err = LexError;
242
243 fn from_str(src: &str) -> Result<TokenStream, LexError> {
244 match imp::TokenStream::from_str_checked(src) {
245 Ok(tokens) => Ok(TokenStream::_new(tokens)),
246 Err(lex) => Err(LexError {
247 inner: lex,
248 _marker: MARKER,
249 }),
250 }
251 }
252}
253
254#[cfg(feature = "proc-macro")]
255#[cfg_attr(docsrs, doc(cfg(feature = "proc-macro")))]
256impl From<proc_macro::TokenStream> for TokenStream {
257 fn from(inner: proc_macro::TokenStream) -> Self {
258 TokenStream::_new(imp::TokenStream::from(inner))
259 }
260}
261
262#[cfg(feature = "proc-macro")]
263#[cfg_attr(docsrs, doc(cfg(feature = "proc-macro")))]
264impl From<TokenStream> for proc_macro::TokenStream {
265 fn from(inner: TokenStream) -> Self {
266 proc_macro::TokenStream::from(inner.inner)
267 }
268}
269
270impl From<TokenTree> for TokenStream {
271 fn from(token: TokenTree) -> Self {
272 TokenStream::_new(imp::TokenStream::from(token))
273 }
274}
275
276impl Extend<TokenTree> for TokenStream {
277 fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I) {
278 self.inner.extend(streams);
279 }
280}
281
282impl Extend<TokenStream> for TokenStream {
283 fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
284 self.inner
285 .extend(streams.into_iter().map(|stream| stream.inner));
286 }
287}
288
289/// Collects a number of token trees into a single stream.
290impl FromIterator<TokenTree> for TokenStream {
291 fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self {
292 TokenStream::_new(streams.into_iter().collect())
293 }
294}
295impl FromIterator<TokenStream> for TokenStream {
296 fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
297 TokenStream::_new(streams.into_iter().map(|i| i.inner).collect())
298 }
299}
300
301/// Prints the token stream as a string that is supposed to be losslessly
302/// convertible back into the same token stream (modulo spans), except for
303/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
304/// numeric literals.
305impl Display for TokenStream {
306 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
307 Display::fmt(&self.inner, f)
308 }
309}
310
311/// Prints token in a form convenient for debugging.
312impl Debug for TokenStream {
313 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
314 Debug::fmt(&self.inner, f)
315 }
316}
317
318impl LexError {
319 pub fn span(&self) -> Span {
320 Span::_new(self.inner.span())
321 }
322}
323
324impl Debug for LexError {
325 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
326 Debug::fmt(&self.inner, f)
327 }
328}
329
330impl Display for LexError {
331 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
332 Display::fmt(&self.inner, f)
333 }
334}
335
336impl Error for LexError {}
337
338/// A region of source code, along with macro expansion information.
339#[derive(Copy, Clone)]
340pub struct Span {
341 inner: imp::Span,
342 _marker: ProcMacroAutoTraits,
343}
344
345impl Span {
346 fn _new(inner: imp::Span) -> Self {
347 Span {
348 inner,
349 _marker: MARKER,
350 }
351 }
352
353 fn _new_fallback(inner: fallback::Span) -> Self {
354 Span {
355 inner: imp::Span::from(inner),
356 _marker: MARKER,
357 }
358 }
359
360 /// The span of the invocation of the current procedural macro.
361 ///
362 /// Identifiers created with this span will be resolved as if they were
363 /// written directly at the macro call location (call-site hygiene) and
364 /// other code at the macro call site will be able to refer to them as well.
365 pub fn call_site() -> Self {
366 Span::_new(imp::Span::call_site())
367 }
368
369 /// The span located at the invocation of the procedural macro, but with
370 /// local variables, labels, and `$crate` resolved at the definition site
371 /// of the macro. This is the same hygiene behavior as `macro_rules`.
372 pub fn mixed_site() -> Self {
373 Span::_new(imp::Span::mixed_site())
374 }
375
376 /// A span that resolves at the macro definition site.
377 ///
378 /// This method is semver exempt and not exposed by default.
379 #[cfg(procmacro2_semver_exempt)]
380 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
381 pub fn def_site() -> Self {
382 Span::_new(imp::Span::def_site())
383 }
384
385 /// Creates a new span with the same line/column information as `self` but
386 /// that resolves symbols as though it were at `other`.
387 pub fn resolved_at(&self, other: Span) -> Span {
388 Span::_new(self.inner.resolved_at(other.inner))
389 }
390
391 /// Creates a new span with the same name resolution behavior as `self` but
392 /// with the line/column information of `other`.
393 pub fn located_at(&self, other: Span) -> Span {
394 Span::_new(self.inner.located_at(other.inner))
395 }
396
397 /// Convert `safe_proc_macro2::Span` to `proc_macro::Span`.
398 ///
399 /// This method is available when building with a nightly compiler, or when
400 /// building with rustc 1.29+ *without* semver exempt features.
401 ///
402 /// # Panics
403 ///
404 /// Panics if called from outside of a procedural macro. Unlike
405 /// `safe_proc_macro2::Span`, the `proc_macro::Span` type can only exist within
406 /// the context of a procedural macro invocation.
407 #[cfg(wrap_proc_macro)]
408 pub fn unwrap(self) -> proc_macro::Span {
409 self.inner.unwrap()
410 }
411
412 // Soft deprecated. Please use Span::unwrap.
413 #[cfg(wrap_proc_macro)]
414 #[doc(hidden)]
415 pub fn unstable(self) -> proc_macro::Span {
416 self.unwrap()
417 }
418
419 /// Returns the span's byte position range in the source file.
420 ///
421 /// This method requires the `"span-locations"` feature to be enabled.
422 ///
423 /// When executing in a procedural macro context, the returned range is only
424 /// accurate if compiled with a nightly toolchain. The stable toolchain does
425 /// not have this information available. When executing outside of a
426 /// procedural macro, such as main.rs or build.rs, the byte range is always
427 /// accurate regardless of toolchain.
428 #[cfg(span_locations)]
429 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
430 pub fn byte_range(&self) -> Range<usize> {
431 self.inner.byte_range()
432 }
433
434 /// Get the starting line/column in the source file for this span.
435 ///
436 /// This method requires the `"span-locations"` feature to be enabled.
437 ///
438 /// When executing in a procedural macro context, the returned line/column
439 /// are only meaningful if compiled with a nightly toolchain. The stable
440 /// toolchain does not have this information available. When executing
441 /// outside of a procedural macro, such as main.rs or build.rs, the
442 /// line/column are always meaningful regardless of toolchain.
443 #[cfg(span_locations)]
444 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
445 pub fn start(&self) -> LineColumn {
446 self.inner.start()
447 }
448
449 /// Get the ending line/column in the source file for this span.
450 ///
451 /// This method requires the `"span-locations"` feature to be enabled.
452 ///
453 /// When executing in a procedural macro context, the returned line/column
454 /// are only meaningful if compiled with a nightly toolchain. The stable
455 /// toolchain does not have this information available. When executing
456 /// outside of a procedural macro, such as main.rs or build.rs, the
457 /// line/column are always meaningful regardless of toolchain.
458 #[cfg(span_locations)]
459 #[cfg_attr(docsrs, doc(cfg(feature = "span-locations")))]
460 pub fn end(&self) -> LineColumn {
461 self.inner.end()
462 }
463
464 /// The path to the source file in which this span occurs, for display
465 /// purposes.
466 ///
467 /// This might not correspond to a valid file system path. It might be
468 /// remapped, or might be an artificial path such as `"<macro expansion>"`.
469 ///
470 /// This method is semver exempt and not exposed by default.
471 #[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
472 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
473 pub fn file(&self) -> String {
474 self.inner.file()
475 }
476
477 /// The path to the source file in which this span occurs on disk.
478 ///
479 /// This is the actual path on disk. It is unaffected by path remapping.
480 ///
481 /// This path should not be embedded in the output of the macro; prefer
482 /// `file()` instead.
483 ///
484 /// This method is semver exempt and not exposed by default.
485 #[cfg(all(procmacro2_semver_exempt, any(not(wrap_proc_macro), super_unstable)))]
486 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
487 pub fn local_file(&self) -> Option<PathBuf> {
488 self.inner.local_file()
489 }
490
491 /// Create a new span encompassing `self` and `other`.
492 ///
493 /// Returns `None` if `self` and `other` are from different files.
494 ///
495 /// Warning: the underlying [`proc_macro::Span::join`] method is
496 /// nightly-only. When called from within a procedural macro not using a
497 /// nightly compiler, this method will always return `None`.
498 pub fn join(&self, other: Span) -> Option<Span> {
499 self.inner.join(other.inner).map(Span::_new)
500 }
501
502 /// Compares two spans to see if they're equal.
503 ///
504 /// This method is semver exempt and not exposed by default.
505 #[cfg(procmacro2_semver_exempt)]
506 #[cfg_attr(docsrs, doc(cfg(procmacro2_semver_exempt)))]
507 pub fn eq(&self, other: &Span) -> bool {
508 self.inner.eq(&other.inner)
509 }
510
511 /// Returns the source text behind a span. This preserves the original
512 /// source code, including spaces and comments. It only returns a result if
513 /// the span corresponds to real source code.
514 ///
515 /// Note: The observable result of a macro should only rely on the tokens
516 /// and not on this source text. The result of this function is a best
517 /// effort to be used for diagnostics only.
518 pub fn source_text(&self) -> Option<String> {
519 self.inner.source_text()
520 }
521}
522
523/// Prints a span in a form convenient for debugging.
524impl Debug for Span {
525 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
526 Debug::fmt(&self.inner, f)
527 }
528}
529
530/// A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`).
531#[derive(Clone)]
532pub enum TokenTree {
533 /// A token stream surrounded by bracket delimiters.
534 Group(Group),
535 /// An identifier.
536 Ident(Ident),
537 /// A single punctuation character (`+`, `,`, `$`, etc.).
538 Punct(Punct),
539 /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
540 Literal(Literal),
541}
542
543impl TokenTree {
544 /// Returns the span of this tree, delegating to the `span` method of
545 /// the contained token or a delimited stream.
546 pub fn span(&self) -> Span {
547 match self {
548 TokenTree::Group(t) => t.span(),
549 TokenTree::Ident(t) => t.span(),
550 TokenTree::Punct(t) => t.span(),
551 TokenTree::Literal(t) => t.span(),
552 }
553 }
554
555 /// Configures the span for *only this token*.
556 ///
557 /// Note that if this token is a `Group` then this method will not configure
558 /// the span of each of the internal tokens, this will simply delegate to
559 /// the `set_span` method of each variant.
560 pub fn set_span(&mut self, span: Span) {
561 match self {
562 TokenTree::Group(t) => t.set_span(span),
563 TokenTree::Ident(t) => t.set_span(span),
564 TokenTree::Punct(t) => t.set_span(span),
565 TokenTree::Literal(t) => t.set_span(span),
566 }
567 }
568}
569
570impl From<Group> for TokenTree {
571 fn from(g: Group) -> Self {
572 TokenTree::Group(g)
573 }
574}
575
576impl From<Ident> for TokenTree {
577 fn from(g: Ident) -> Self {
578 TokenTree::Ident(g)
579 }
580}
581
582impl From<Punct> for TokenTree {
583 fn from(g: Punct) -> Self {
584 TokenTree::Punct(g)
585 }
586}
587
588impl From<Literal> for TokenTree {
589 fn from(g: Literal) -> Self {
590 TokenTree::Literal(g)
591 }
592}
593
594/// Prints the token tree as a string that is supposed to be losslessly
595/// convertible back into the same token tree (modulo spans), except for
596/// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
597/// numeric literals.
598impl Display for TokenTree {
599 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
600 match self {
601 TokenTree::Group(t) => Display::fmt(t, f),
602 TokenTree::Ident(t) => Display::fmt(t, f),
603 TokenTree::Punct(t) => Display::fmt(t, f),
604 TokenTree::Literal(t) => Display::fmt(t, f),
605 }
606 }
607}
608
609/// Prints token tree in a form convenient for debugging.
610impl Debug for TokenTree {
611 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
612 // Each of these has the name in the struct type in the derived debug,
613 // so don't bother with an extra layer of indirection
614 match self {
615 TokenTree::Group(t) => Debug::fmt(t, f),
616 TokenTree::Ident(t) => {
617 let mut debug = f.debug_struct("Ident");
618 debug.field("sym", &format_args!("{}", t));
619 imp::debug_span_field_if_nontrivial(&mut debug, t.span().inner);
620 debug.finish()
621 }
622 TokenTree::Punct(t) => Debug::fmt(t, f),
623 TokenTree::Literal(t) => Debug::fmt(t, f),
624 }
625 }
626}
627
628/// A delimited token stream.
629///
630/// A `Group` internally contains a `TokenStream` which is surrounded by
631/// `Delimiter`s.
632#[derive(Clone)]
633pub struct Group {
634 inner: imp::Group,
635}
636
637/// Describes how a sequence of token trees is delimited.
638#[derive(Copy, Clone, Debug, Eq, PartialEq)]
639pub enum Delimiter {
640 /// `( ... )`
641 Parenthesis,
642 /// `{ ... }`
643 Brace,
644 /// `[ ... ]`
645 Bracket,
646 /// `∅ ... ∅`
647 ///
648 /// An invisible delimiter, that may, for example, appear around tokens
649 /// coming from a "macro variable" `$var`. It is important to preserve
650 /// operator priorities in cases like `$var * 3` where `$var` is `1 + 2`.
651 /// Invisible delimiters may not survive roundtrip of a token stream through
652 /// a string.
653 ///
654 /// <div class="warning">
655 ///
656 /// Note: rustc currently can ignore the grouping of tokens delimited by `None` in the output
657 /// of a proc_macro. Only `None`-delimited groups created by a macro_rules macro in the input
658 /// of a proc_macro macro are preserved, and only in very specific circumstances.
659 /// Any `None`-delimited groups (re)created by a proc_macro will therefore not preserve
660 /// operator priorities as indicated above. The other `Delimiter` variants should be used
661 /// instead in this context. This is a rustc bug. For details, see
662 /// [rust-lang/rust#67062](https://github.com/rust-lang/rust/issues/67062).
663 ///
664 /// </div>
665 None,
666}
667
668impl Group {
669 fn _new(inner: imp::Group) -> Self {
670 Group { inner }
671 }
672
673 fn _new_fallback(inner: fallback::Group) -> Self {
674 Group {
675 inner: imp::Group::from(inner),
676 }
677 }
678
679 /// Creates a new `Group` with the given delimiter and token stream.
680 ///
681 /// This constructor will set the span for this group to
682 /// `Span::call_site()`. To change the span you can use the `set_span`
683 /// method below.
684 pub fn new(delimiter: Delimiter, stream: TokenStream) -> Self {
685 Group {
686 inner: imp::Group::new(delimiter, stream.inner),
687 }
688 }
689
690 /// Returns the punctuation used as the delimiter for this group: a set of
691 /// parentheses, square brackets, or curly braces.
692 pub fn delimiter(&self) -> Delimiter {
693 self.inner.delimiter()
694 }
695
696 /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
697 ///
698 /// Note that the returned token stream does not include the delimiter
699 /// returned above.
700 pub fn stream(&self) -> TokenStream {
701 TokenStream::_new(self.inner.stream())
702 }
703
704 /// Returns the span for the delimiters of this token stream, spanning the
705 /// entire `Group`.
706 ///
707 /// ```text
708 /// pub fn span(&self) -> Span {
709 /// ^^^^^^^
710 /// ```
711 pub fn span(&self) -> Span {
712 Span::_new(self.inner.span())
713 }
714
715 /// Returns the span pointing to the opening delimiter of this group.
716 ///
717 /// ```text
718 /// pub fn span_open(&self) -> Span {
719 /// ^
720 /// ```
721 pub fn span_open(&self) -> Span {
722 Span::_new(self.inner.span_open())
723 }
724
725 /// Returns the span pointing to the closing delimiter of this group.
726 ///
727 /// ```text
728 /// pub fn span_close(&self) -> Span {
729 /// ^
730 /// ```
731 pub fn span_close(&self) -> Span {
732 Span::_new(self.inner.span_close())
733 }
734
735 /// Returns an object that holds this group's `span_open()` and
736 /// `span_close()` together (in a more compact representation than holding
737 /// those 2 spans individually).
738 pub fn delim_span(&self) -> DelimSpan {
739 DelimSpan::new(&self.inner)
740 }
741
742 /// Configures the span for this `Group`'s delimiters, but not its internal
743 /// tokens.
744 ///
745 /// This method will **not** set the span of all the internal tokens spanned
746 /// by this group, but rather it will only set the span of the delimiter
747 /// tokens at the level of the `Group`.
748 pub fn set_span(&mut self, span: Span) {
749 self.inner.set_span(span.inner);
750 }
751}
752
753/// Prints the group as a string that should be losslessly convertible back
754/// into the same group (modulo spans), except for possibly `TokenTree::Group`s
755/// with `Delimiter::None` delimiters.
756impl Display for Group {
757 fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
758 Display::fmt(&self.inner, formatter)
759 }
760}
761
762impl Debug for Group {
763 fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
764 Debug::fmt(&self.inner, formatter)
765 }
766}
767
768/// A `Punct` is a single punctuation character like `+`, `-` or `#`.
769///
770/// Multicharacter operators like `+=` are represented as two instances of
771/// `Punct` with different forms of `Spacing` returned.
772#[derive(Clone)]
773pub struct Punct {
774 ch: char,
775 spacing: Spacing,
776 span: Span,
777}
778
779/// Whether a `Punct` is followed immediately by another `Punct` or followed by
780/// another token or whitespace.
781#[derive(Copy, Clone, Debug, Eq, PartialEq)]
782pub enum Spacing {
783 /// E.g. `+` is `Alone` in `+ =`, `+ident` or `+()`.
784 Alone,
785 /// E.g. `+` is `Joint` in `+=` or `'` is `Joint` in `'#`.
786 ///
787 /// Additionally, single quote `'` can join with identifiers to form
788 /// lifetimes `'ident`.
789 Joint,
790}
791
792impl Punct {
793 /// Creates a new `Punct` from the given character and spacing.
794 ///
795 /// The `ch` argument must be a valid punctuation character permitted by the
796 /// language, otherwise the function will panic.
797 ///
798 /// The returned `Punct` will have the default span of `Span::call_site()`
799 /// which can be further configured with the `set_span` method below.
800 pub fn new(ch: char, spacing: Spacing) -> Self {
801 if let '!' | '#' | '$' | '%' | '&' | '\'' | '*' | '+' | ',' | '-' | '.' | '/' | ':' | ';'
802 | '<' | '=' | '>' | '?' | '@' | '^' | '|' | '~' = ch
803 {
804 Punct {
805 ch,
806 spacing,
807 span: Span::call_site(),
808 }
809 } else {
810 panic!("unsupported proc macro punctuation character {:?}", ch);
811 }
812 }
813
814 /// Returns the value of this punctuation character as `char`.
815 pub fn as_char(&self) -> char {
816 self.ch
817 }
818
819 /// Returns the spacing of this punctuation character, indicating whether
820 /// it's immediately followed by another `Punct` in the token stream, so
821 /// they can potentially be combined into a multicharacter operator
822 /// (`Joint`), or it's followed by some other token or whitespace (`Alone`)
823 /// so the operator has certainly ended.
824 pub fn spacing(&self) -> Spacing {
825 self.spacing
826 }
827
828 /// Returns the span for this punctuation character.
829 pub fn span(&self) -> Span {
830 self.span
831 }
832
833 /// Configure the span for this punctuation character.
834 pub fn set_span(&mut self, span: Span) {
835 self.span = span;
836 }
837}
838
839/// Prints the punctuation character as a string that should be losslessly
840/// convertible back into the same character.
841impl Display for Punct {
842 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
843 Display::fmt(&self.ch, f)
844 }
845}
846
847impl Debug for Punct {
848 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
849 let mut debug = fmt.debug_struct("Punct");
850 debug.field("char", &self.ch);
851 debug.field("spacing", &self.spacing);
852 imp::debug_span_field_if_nontrivial(&mut debug, self.span.inner);
853 debug.finish()
854 }
855}
856
857/// A word of Rust code, which may be a keyword or legal variable name.
858///
859/// An identifier consists of at least one Unicode code point, the first of
860/// which has the XID_Start property and the rest of which have the XID_Continue
861/// property.
862///
863/// - The empty string is not an identifier. Use `Option<Ident>`.
864/// - A lifetime is not an identifier. Use `syn::Lifetime` instead.
865///
866/// An identifier constructed with `Ident::new` is permitted to be a Rust
867/// keyword, though parsing one through its [`Parse`] implementation rejects
868/// Rust keywords. Use `input.call(Ident::parse_any)` when parsing to match the
869/// behaviour of `Ident::new`.
870///
871/// [`Parse`]: https://docs.rs/syn/2.0/syn/parse/trait.Parse.html
872///
873/// # Examples
874///
875/// A new ident can be created from a string using the `Ident::new` function.
876/// A span must be provided explicitly which governs the name resolution
877/// behavior of the resulting identifier.
878///
879/// ```
880/// use safe_proc_macro2::{Ident, Span};
881///
882/// fn main() {
883/// let call_ident = Ident::new("calligraphy", Span::call_site());
884///
885/// println!("{}", call_ident);
886/// }
887/// ```
888///
889/// An ident can be interpolated into a token stream using the `quote!` macro.
890///
891/// ```
892/// use safe_proc_macro2::{Ident, Span};
893/// use safe_quote::quote;
894///
895/// fn main() {
896/// let ident = Ident::new("demo", Span::call_site());
897///
898/// // Create a variable binding whose name is this ident.
899/// let expanded = quote! { let #ident = 10; };
900///
901/// // Create a variable binding with a slightly different name.
902/// let temp_ident = Ident::new(&format!("new_{}", ident), Span::call_site());
903/// let expanded = quote! { let #temp_ident = 10; };
904/// }
905/// ```
906///
907/// A string representation of the ident is available through the `to_string()`
908/// method.
909///
910/// ```
911/// # use safe_proc_macro2::{Ident, Span};
912/// #
913/// # let ident = Ident::new("another_identifier", Span::call_site());
914/// #
915/// // Examine the ident as a string.
916/// let ident_string = ident.to_string();
917/// if ident_string.len() > 60 {
918/// println!("Very long identifier: {}", ident_string)
919/// }
920/// ```
921#[derive(Clone)]
922pub struct Ident {
923 inner: imp::Ident,
924 _marker: ProcMacroAutoTraits,
925}
926
927impl Ident {
928 fn _new(inner: imp::Ident) -> Self {
929 Ident {
930 inner,
931 _marker: MARKER,
932 }
933 }
934
935 fn _new_fallback(inner: fallback::Ident) -> Self {
936 Ident {
937 inner: imp::Ident::from(inner),
938 _marker: MARKER,
939 }
940 }
941
942 /// Creates a new `Ident` with the given `string` as well as the specified
943 /// `span`.
944 ///
945 /// The `string` argument must be a valid identifier permitted by the
946 /// language, otherwise the function will panic.
947 ///
948 /// Note that `span`, currently in rustc, configures the hygiene information
949 /// for this identifier.
950 ///
951 /// As of this time `Span::call_site()` explicitly opts-in to "call-site"
952 /// hygiene meaning that identifiers created with this span will be resolved
953 /// as if they were written directly at the location of the macro call, and
954 /// other code at the macro call site will be able to refer to them as well.
955 ///
956 /// Later spans like `Span::def_site()` will allow to opt-in to
957 /// "definition-site" hygiene meaning that identifiers created with this
958 /// span will be resolved at the location of the macro definition and other
959 /// code at the macro call site will not be able to refer to them.
960 ///
961 /// Due to the current importance of hygiene this constructor, unlike other
962 /// tokens, requires a `Span` to be specified at construction.
963 ///
964 /// # Panics
965 ///
966 /// Panics if the input string is neither a keyword nor a legal variable
967 /// name. If you are not sure whether the string contains an identifier and
968 /// need to handle an error case, use
969 /// <a href="https://docs.rs/syn/2.0/syn/fn.parse_str.html"><code
970 /// style="padding-right:0;">syn::parse_str</code></a><code
971 /// style="padding-left:0;">::<Ident></code>
972 /// rather than `Ident::new`.
973 #[track_caller]
974 pub fn new(string: &str, span: Span) -> Self {
975 Ident::_new(imp::Ident::new_checked(string, span.inner))
976 }
977
978 /// Same as `Ident::new`, but creates a raw identifier (`r#ident`). The
979 /// `string` argument must be a valid identifier permitted by the language
980 /// (including keywords, e.g. `fn`). Keywords which are usable in path
981 /// segments (e.g. `self`, `super`) are not supported, and will cause a
982 /// panic.
983 #[track_caller]
984 pub fn new_raw(string: &str, span: Span) -> Self {
985 Ident::_new(imp::Ident::new_raw_checked(string, span.inner))
986 }
987
988 /// Returns the span of this `Ident`.
989 pub fn span(&self) -> Span {
990 Span::_new(self.inner.span())
991 }
992
993 /// Configures the span of this `Ident`, possibly changing its hygiene
994 /// context.
995 pub fn set_span(&mut self, span: Span) {
996 self.inner.set_span(span.inner);
997 }
998}
999
1000impl PartialEq for Ident {
1001 fn eq(&self, other: &Ident) -> bool {
1002 self.inner == other.inner
1003 }
1004}
1005
1006impl<T> PartialEq<T> for Ident
1007where
1008 T: ?Sized + AsRef<str>,
1009{
1010 fn eq(&self, other: &T) -> bool {
1011 self.inner == other
1012 }
1013}
1014
1015impl Eq for Ident {}
1016
1017impl PartialOrd for Ident {
1018 fn partial_cmp(&self, other: &Ident) -> Option<Ordering> {
1019 Some(self.cmp(other))
1020 }
1021}
1022
1023impl Ord for Ident {
1024 fn cmp(&self, other: &Ident) -> Ordering {
1025 self.to_string().cmp(&other.to_string())
1026 }
1027}
1028
1029impl Hash for Ident {
1030 fn hash<H: Hasher>(&self, hasher: &mut H) {
1031 self.to_string().hash(hasher);
1032 }
1033}
1034
1035/// Prints the identifier as a string that should be losslessly convertible back
1036/// into the same identifier.
1037impl Display for Ident {
1038 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1039 Display::fmt(&self.inner, f)
1040 }
1041}
1042
1043impl Debug for Ident {
1044 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1045 Debug::fmt(&self.inner, f)
1046 }
1047}
1048
1049/// A literal string (`"hello"`), byte string (`b"hello"`), character (`'a'`),
1050/// byte character (`b'a'`), an integer or floating point number with or without
1051/// a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
1052///
1053/// Boolean literals like `true` and `false` do not belong here, they are
1054/// `Ident`s.
1055#[derive(Clone)]
1056pub struct Literal {
1057 inner: imp::Literal,
1058 _marker: ProcMacroAutoTraits,
1059}
1060
1061macro_rules! suffixed_int_literals {
1062 ($($name:ident => $kind:ident,)*) => ($(
1063 /// Creates a new suffixed integer literal with the specified value.
1064 ///
1065 /// This function will create an integer like `1u32` where the integer
1066 /// value specified is the first part of the token and the integral is
1067 /// also suffixed at the end. Literals created from negative numbers may
1068 /// not survive roundtrips through `TokenStream` or strings and may be
1069 /// broken into two tokens (`-` and positive literal).
1070 ///
1071 /// Literals created through this method have the `Span::call_site()`
1072 /// span by default, which can be configured with the `set_span` method
1073 /// below.
1074 pub fn $name(n: $kind) -> Literal {
1075 Literal::_new(imp::Literal::$name(n))
1076 }
1077 )*)
1078}
1079
1080macro_rules! unsuffixed_int_literals {
1081 ($($name:ident => $kind:ident,)*) => ($(
1082 /// Creates a new unsuffixed integer literal with the specified value.
1083 ///
1084 /// This function will create an integer like `1` where the integer
1085 /// value specified is the first part of the token. No suffix is
1086 /// specified on this token, meaning that invocations like
1087 /// `Literal::i8_unsuffixed(1)` are equivalent to
1088 /// `Literal::u32_unsuffixed(1)`. Literals created from negative numbers
1089 /// may not survive roundtrips through `TokenStream` or strings and may
1090 /// be broken into two tokens (`-` and positive literal).
1091 ///
1092 /// Literals created through this method have the `Span::call_site()`
1093 /// span by default, which can be configured with the `set_span` method
1094 /// below.
1095 pub fn $name(n: $kind) -> Literal {
1096 Literal::_new(imp::Literal::$name(n))
1097 }
1098 )*)
1099}
1100
1101impl Literal {
1102 fn _new(inner: imp::Literal) -> Self {
1103 Literal {
1104 inner,
1105 _marker: MARKER,
1106 }
1107 }
1108
1109 fn _new_fallback(inner: fallback::Literal) -> Self {
1110 Literal {
1111 inner: imp::Literal::from(inner),
1112 _marker: MARKER,
1113 }
1114 }
1115
1116 suffixed_int_literals! {
1117 u8_suffixed => u8,
1118 u16_suffixed => u16,
1119 u32_suffixed => u32,
1120 u64_suffixed => u64,
1121 u128_suffixed => u128,
1122 usize_suffixed => usize,
1123 i8_suffixed => i8,
1124 i16_suffixed => i16,
1125 i32_suffixed => i32,
1126 i64_suffixed => i64,
1127 i128_suffixed => i128,
1128 isize_suffixed => isize,
1129 }
1130
1131 unsuffixed_int_literals! {
1132 u8_unsuffixed => u8,
1133 u16_unsuffixed => u16,
1134 u32_unsuffixed => u32,
1135 u64_unsuffixed => u64,
1136 u128_unsuffixed => u128,
1137 usize_unsuffixed => usize,
1138 i8_unsuffixed => i8,
1139 i16_unsuffixed => i16,
1140 i32_unsuffixed => i32,
1141 i64_unsuffixed => i64,
1142 i128_unsuffixed => i128,
1143 isize_unsuffixed => isize,
1144 }
1145
1146 /// Creates a new unsuffixed floating-point literal.
1147 ///
1148 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1149 /// the float's value is emitted directly into the token but no suffix is
1150 /// used, so it may be inferred to be a `f64` later in the compiler.
1151 /// Literals created from negative numbers may not survive round-trips
1152 /// through `TokenStream` or strings and may be broken into two tokens (`-`
1153 /// and positive literal).
1154 ///
1155 /// # Panics
1156 ///
1157 /// This function requires that the specified float is finite, for example
1158 /// if it is infinity or NaN this function will panic.
1159 pub fn f64_unsuffixed(f: f64) -> Literal {
1160 assert!(f.is_finite());
1161 Literal::_new(imp::Literal::f64_unsuffixed(f))
1162 }
1163
1164 /// Creates a new suffixed floating-point literal.
1165 ///
1166 /// This constructor will create a literal like `1.0f64` where the value
1167 /// specified is the preceding part of the token and `f64` is the suffix of
1168 /// the token. This token will always be inferred to be an `f64` in the
1169 /// compiler. Literals created from negative numbers may not survive
1170 /// round-trips through `TokenStream` or strings and may be broken into two
1171 /// tokens (`-` and positive literal).
1172 ///
1173 /// # Panics
1174 ///
1175 /// This function requires that the specified float is finite, for example
1176 /// if it is infinity or NaN this function will panic.
1177 pub fn f64_suffixed(f: f64) -> Literal {
1178 assert!(f.is_finite());
1179 Literal::_new(imp::Literal::f64_suffixed(f))
1180 }
1181
1182 /// Creates a new unsuffixed floating-point literal.
1183 ///
1184 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1185 /// the float's value is emitted directly into the token but no suffix is
1186 /// used, so it may be inferred to be a `f64` later in the compiler.
1187 /// Literals created from negative numbers may not survive round-trips
1188 /// through `TokenStream` or strings and may be broken into two tokens (`-`
1189 /// and positive literal).
1190 ///
1191 /// # Panics
1192 ///
1193 /// This function requires that the specified float is finite, for example
1194 /// if it is infinity or NaN this function will panic.
1195 pub fn f32_unsuffixed(f: f32) -> Literal {
1196 assert!(f.is_finite());
1197 Literal::_new(imp::Literal::f32_unsuffixed(f))
1198 }
1199
1200 /// Creates a new suffixed floating-point literal.
1201 ///
1202 /// This constructor will create a literal like `1.0f32` where the value
1203 /// specified is the preceding part of the token and `f32` is the suffix of
1204 /// the token. This token will always be inferred to be an `f32` in the
1205 /// compiler. Literals created from negative numbers may not survive
1206 /// round-trips through `TokenStream` or strings and may be broken into two
1207 /// tokens (`-` and positive literal).
1208 ///
1209 /// # Panics
1210 ///
1211 /// This function requires that the specified float is finite, for example
1212 /// if it is infinity or NaN this function will panic.
1213 pub fn f32_suffixed(f: f32) -> Literal {
1214 assert!(f.is_finite());
1215 Literal::_new(imp::Literal::f32_suffixed(f))
1216 }
1217
1218 /// String literal.
1219 pub fn string(string: &str) -> Literal {
1220 Literal::_new(imp::Literal::string(string))
1221 }
1222
1223 /// Character literal.
1224 pub fn character(ch: char) -> Literal {
1225 Literal::_new(imp::Literal::character(ch))
1226 }
1227
1228 /// Byte character literal.
1229 pub fn byte_character(byte: u8) -> Literal {
1230 Literal::_new(imp::Literal::byte_character(byte))
1231 }
1232
1233 /// Byte string literal.
1234 pub fn byte_string(bytes: &[u8]) -> Literal {
1235 Literal::_new(imp::Literal::byte_string(bytes))
1236 }
1237
1238 /// C string literal.
1239 pub fn c_string(string: &CStr) -> Literal {
1240 Literal::_new(imp::Literal::c_string(string))
1241 }
1242
1243 /// Returns the span encompassing this literal.
1244 pub fn span(&self) -> Span {
1245 Span::_new(self.inner.span())
1246 }
1247
1248 /// Configures the span associated for this literal.
1249 pub fn set_span(&mut self, span: Span) {
1250 self.inner.set_span(span.inner);
1251 }
1252
1253 /// Returns a `Span` that is a subset of `self.span()` containing only
1254 /// the source bytes in range `range`. Returns `None` if the would-be
1255 /// trimmed span is outside the bounds of `self`.
1256 ///
1257 /// Warning: the underlying [`proc_macro::Literal::subspan`] method is
1258 /// nightly-only. When called from within a procedural macro not using a
1259 /// nightly compiler, this method will always return `None`.
1260 pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
1261 self.inner.subspan(range).map(Span::_new)
1262 }
1263
1264 // Intended for the `quote!` macro to use when constructing a proc-macro2
1265 // token out of a macro_rules $:literal token, which is already known to be
1266 // a valid literal. This avoids reparsing/validating the literal's string
1267 // representation. This is not public API other than for quote.
1268 #[doc(hidden)]
1269 pub fn from_str_unchecked(repr: &str) -> Self {
1270 Literal::_new(imp::Literal::from_str_unchecked(repr))
1271 }
1272}
1273
1274impl FromStr for Literal {
1275 type Err = LexError;
1276
1277 fn from_str(repr: &str) -> Result<Self, LexError> {
1278 match imp::Literal::from_str_checked(repr) {
1279 Ok(lit) => Ok(Literal::_new(lit)),
1280 Err(lex) => Err(LexError {
1281 inner: lex,
1282 _marker: MARKER,
1283 }),
1284 }
1285 }
1286}
1287
1288impl Debug for Literal {
1289 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1290 Debug::fmt(&self.inner, f)
1291 }
1292}
1293
1294impl Display for Literal {
1295 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1296 Display::fmt(&self.inner, f)
1297 }
1298}
1299
1300/// Public implementation details for the `TokenStream` type, such as iterators.
1301pub mod token_stream {
1302 use crate::marker::{ProcMacroAutoTraits, MARKER};
1303 use crate::{imp, TokenTree};
1304 use core::fmt::{self, Debug};
1305
1306 pub use crate::TokenStream;
1307
1308 /// An iterator over `TokenStream`'s `TokenTree`s.
1309 ///
1310 /// The iteration is "shallow", e.g. the iterator doesn't recurse into
1311 /// delimited groups, and returns whole groups as token trees.
1312 #[derive(Clone)]
1313 pub struct IntoIter {
1314 inner: imp::TokenTreeIter,
1315 _marker: ProcMacroAutoTraits,
1316 }
1317
1318 impl Iterator for IntoIter {
1319 type Item = TokenTree;
1320
1321 fn next(&mut self) -> Option<TokenTree> {
1322 self.inner.next()
1323 }
1324
1325 fn size_hint(&self) -> (usize, Option<usize>) {
1326 self.inner.size_hint()
1327 }
1328 }
1329
1330 impl Debug for IntoIter {
1331 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1332 f.write_str("TokenStream ")?;
1333 f.debug_list().entries(self.clone()).finish()
1334 }
1335 }
1336
1337 impl IntoIterator for TokenStream {
1338 type Item = TokenTree;
1339 type IntoIter = IntoIter;
1340
1341 fn into_iter(self) -> IntoIter {
1342 IntoIter {
1343 inner: self.inner.into_iter(),
1344 _marker: MARKER,
1345 }
1346 }
1347 }
1348}