1//! A support library for macro authors when defining new macros.
2//!
3//! This library, provided by the standard distribution, provides the types
4//! consumed in the interfaces of procedurally defined macro definitions such as
5//! function-like macros `#[proc_macro]`, macro attributes `#[proc_macro_attribute]` and
6//! custom derive attributes`#[proc_macro_derive]`.
7//!
8//! See [the book] for more.
9//!
10//! [the book]: ../book/ch19-06-macros.html#procedural-macros-for-generating-code-from-attributes
11
12#![stable(feature = "proc_macro_lib", since = "1.15.0")]
13#![deny(missing_docs)]
14#![doc(
15 html_playground_url = "https://play.rust-lang.org/",
16 issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
17 test(no_crate_inject, attr(deny(warnings))),
18 test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
19)]
20#![doc(rust_logo)]
21#![feature(rustdoc_internals)]
22#![feature(staged_api)]
23#![feature(allow_internal_unstable)]
24#![feature(decl_macro)]
25#![feature(maybe_uninit_write_slice)]
26#![feature(negative_impls)]
27#![feature(panic_can_unwind)]
28#![feature(restricted_std)]
29#![feature(rustc_attrs)]
30#![feature(stmt_expr_attributes)]
31#![feature(extend_one)]
32#![recursion_limit = "256"]
33#![allow(internal_features)]
34#![deny(ffi_unwind_calls)]
35#![allow(rustc::internal)] // Can't use FxHashMap when compiled as part of the standard library
36#![warn(rustdoc::unescaped_backticks)]
37#![warn(unreachable_pub)]
38#![deny(unsafe_op_in_unsafe_fn)]
39
40#[unstable(feature = "proc_macro_internals", issue = "27812")]
41#[doc(hidden)]
42pub mod bridge;
43
44mod diagnostic;
45mod escape;
46mod to_tokens;
47
48use std::ffi::CStr;
49use std::ops::{Range, RangeBounds};
50use std::path::PathBuf;
51use std::str::FromStr;
52use std::{error, fmt};
53
54#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
55pub use diagnostic::{Diagnostic, Level, MultiSpan};
56#[unstable(feature = "proc_macro_value", issue = "136652")]
57pub use rustc_literal_escaper::EscapeError;
58use rustc_literal_escaper::{MixedUnit, Mode, byte_from_char, unescape_mixed, unescape_unicode};
59#[unstable(feature = "proc_macro_totokens", issue = "130977")]
60pub use to_tokens::ToTokens;
61
62use crate::escape::{EscapeOptions, escape_bytes};
63
64/// Errors returned when trying to retrieve a literal unescaped value.
65#[unstable(feature = "proc_macro_value", issue = "136652")]
66#[derive(Debug, PartialEq, Eq)]
67pub enum ConversionErrorKind {
68 /// The literal failed to be escaped, take a look at [`EscapeError`] for more information.
69 FailedToUnescape(EscapeError),
70 /// Trying to convert a literal with the wrong type.
71 InvalidLiteralKind,
72}
73
74/// Determines whether proc_macro has been made accessible to the currently
75/// running program.
76///
77/// The proc_macro crate is only intended for use inside the implementation of
78/// procedural macros. All the functions in this crate panic if invoked from
79/// outside of a procedural macro, such as from a build script or unit test or
80/// ordinary Rust binary.
81///
82/// With consideration for Rust libraries that are designed to support both
83/// macro and non-macro use cases, `proc_macro::is_available()` provides a
84/// non-panicking way to detect whether the infrastructure required to use the
85/// API of proc_macro is presently available. Returns true if invoked from
86/// inside of a procedural macro, false if invoked from any other binary.
87#[stable(feature = "proc_macro_is_available", since = "1.57.0")]
88pub fn is_available() -> bool {
89 bridge::client::is_available()
90}
91
92/// The main type provided by this crate, representing an abstract stream of
93/// tokens, or, more specifically, a sequence of token trees.
94/// The type provides interfaces for iterating over those token trees and, conversely,
95/// collecting a number of token trees into one stream.
96///
97/// This is both the input and output of `#[proc_macro]`, `#[proc_macro_attribute]`
98/// and `#[proc_macro_derive]` definitions.
99#[cfg_attr(feature = "rustc-dep-of-std", rustc_diagnostic_item = "TokenStream")]
100#[stable(feature = "proc_macro_lib", since = "1.15.0")]
101#[derive(Clone)]
102pub struct TokenStream(Option<bridge::client::TokenStream>);
103
104#[stable(feature = "proc_macro_lib", since = "1.15.0")]
105impl !Send for TokenStream {}
106#[stable(feature = "proc_macro_lib", since = "1.15.0")]
107impl !Sync for TokenStream {}
108
109/// Error returned from `TokenStream::from_str`.
110#[stable(feature = "proc_macro_lib", since = "1.15.0")]
111#[non_exhaustive]
112#[derive(Debug)]
113pub struct LexError;
114
115#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
116impl fmt::Display for LexError {
117 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
118 f.write_str(data:"cannot parse string into token stream")
119 }
120}
121
122#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
123impl error::Error for LexError {}
124
125#[stable(feature = "proc_macro_lib", since = "1.15.0")]
126impl !Send for LexError {}
127#[stable(feature = "proc_macro_lib", since = "1.15.0")]
128impl !Sync for LexError {}
129
130/// Error returned from `TokenStream::expand_expr`.
131#[unstable(feature = "proc_macro_expand", issue = "90765")]
132#[non_exhaustive]
133#[derive(Debug)]
134pub struct ExpandError;
135
136#[unstable(feature = "proc_macro_expand", issue = "90765")]
137impl fmt::Display for ExpandError {
138 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
139 f.write_str(data:"macro expansion failed")
140 }
141}
142
143#[unstable(feature = "proc_macro_expand", issue = "90765")]
144impl error::Error for ExpandError {}
145
146#[unstable(feature = "proc_macro_expand", issue = "90765")]
147impl !Send for ExpandError {}
148
149#[unstable(feature = "proc_macro_expand", issue = "90765")]
150impl !Sync for ExpandError {}
151
152impl TokenStream {
153 /// Returns an empty `TokenStream` containing no token trees.
154 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
155 pub fn new() -> TokenStream {
156 TokenStream(None)
157 }
158
159 /// Checks if this `TokenStream` is empty.
160 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
161 pub fn is_empty(&self) -> bool {
162 self.0.as_ref().map(|h| h.is_empty()).unwrap_or(true)
163 }
164
165 /// Parses this `TokenStream` as an expression and attempts to expand any
166 /// macros within it. Returns the expanded `TokenStream`.
167 ///
168 /// Currently only expressions expanding to literals will succeed, although
169 /// this may be relaxed in the future.
170 ///
171 /// NOTE: In error conditions, `expand_expr` may leave macros unexpanded,
172 /// report an error, failing compilation, and/or return an `Err(..)`. The
173 /// specific behavior for any error condition, and what conditions are
174 /// considered errors, is unspecified and may change in the future.
175 #[unstable(feature = "proc_macro_expand", issue = "90765")]
176 pub fn expand_expr(&self) -> Result<TokenStream, ExpandError> {
177 let stream = self.0.as_ref().ok_or(ExpandError)?;
178 match bridge::client::TokenStream::expand_expr(stream) {
179 Ok(stream) => Ok(TokenStream(Some(stream))),
180 Err(_) => Err(ExpandError),
181 }
182 }
183}
184
185/// Attempts to break the string into tokens and parse those tokens into a token stream.
186/// May fail for a number of reasons, for example, if the string contains unbalanced delimiters
187/// or characters not existing in the language.
188/// All tokens in the parsed stream get `Span::call_site()` spans.
189///
190/// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to
191/// change these errors into `LexError`s later.
192#[stable(feature = "proc_macro_lib", since = "1.15.0")]
193impl FromStr for TokenStream {
194 type Err = LexError;
195
196 fn from_str(src: &str) -> Result<TokenStream, LexError> {
197 Ok(TokenStream(Some(bridge::client::TokenStream::from_str(src))))
198 }
199}
200
201/// Prints the token stream as a string that is supposed to be losslessly convertible back
202/// into the same token stream (modulo spans), except for possibly `TokenTree::Group`s
203/// with `Delimiter::None` delimiters and negative numeric literals.
204///
205/// Note: the exact form of the output is subject to change, e.g. there might
206/// be changes in the whitespace used between tokens. Therefore, you should
207/// *not* do any kind of simple substring matching on the output string (as
208/// produced by `to_string`) to implement a proc macro, because that matching
209/// might stop working if such changes happen. Instead, you should work at the
210/// `TokenTree` level, e.g. matching against `TokenTree::Ident`,
211/// `TokenTree::Punct`, or `TokenTree::Literal`.
212#[stable(feature = "proc_macro_lib", since = "1.15.0")]
213impl fmt::Display for TokenStream {
214 #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
215 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
216 match &self.0 {
217 Some(ts: &TokenStream) => write!(f, "{}", ts.to_string()),
218 None => Ok(()),
219 }
220 }
221}
222
223/// Prints token in a form convenient for debugging.
224#[stable(feature = "proc_macro_lib", since = "1.15.0")]
225impl fmt::Debug for TokenStream {
226 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
227 f.write_str(data:"TokenStream ")?;
228 f.debug_list().entries(self.clone()).finish()
229 }
230}
231
232#[stable(feature = "proc_macro_token_stream_default", since = "1.45.0")]
233impl Default for TokenStream {
234 fn default() -> Self {
235 TokenStream::new()
236 }
237}
238
239#[unstable(feature = "proc_macro_quote", issue = "54722")]
240pub use quote::{quote, quote_span};
241
242fn tree_to_bridge_tree(
243 tree: TokenTree,
244) -> bridge::TokenTree<bridge::client::TokenStream, bridge::client::Span, bridge::client::Symbol> {
245 match tree {
246 TokenTree::Group(tt: Group) => bridge::TokenTree::Group(tt.0),
247 TokenTree::Punct(tt: Punct) => bridge::TokenTree::Punct(tt.0),
248 TokenTree::Ident(tt: Ident) => bridge::TokenTree::Ident(tt.0),
249 TokenTree::Literal(tt: Literal) => bridge::TokenTree::Literal(tt.0),
250 }
251}
252
253/// Creates a token stream containing a single token tree.
254#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
255impl From<TokenTree> for TokenStream {
256 fn from(tree: TokenTree) -> TokenStream {
257 TokenStream(Some(bridge::client::TokenStream::from_token_tree(tree_to_bridge_tree(tree))))
258 }
259}
260
261/// Non-generic helper for implementing `FromIterator<TokenTree>` and
262/// `Extend<TokenTree>` with less monomorphization in calling crates.
263struct ConcatTreesHelper {
264 trees: Vec<
265 bridge::TokenTree<
266 bridge::client::TokenStream,
267 bridge::client::Span,
268 bridge::client::Symbol,
269 >,
270 >,
271}
272
273impl ConcatTreesHelper {
274 fn new(capacity: usize) -> Self {
275 ConcatTreesHelper { trees: Vec::with_capacity(capacity) }
276 }
277
278 fn push(&mut self, tree: TokenTree) {
279 self.trees.push(tree_to_bridge_tree(tree));
280 }
281
282 fn build(self) -> TokenStream {
283 if self.trees.is_empty() {
284 TokenStream(None)
285 } else {
286 TokenStream(Some(bridge::client::TokenStream::concat_trees(base:None, self.trees)))
287 }
288 }
289
290 fn append_to(self, stream: &mut TokenStream) {
291 if self.trees.is_empty() {
292 return;
293 }
294 stream.0 = Some(bridge::client::TokenStream::concat_trees(base:stream.0.take(), self.trees))
295 }
296}
297
298/// Non-generic helper for implementing `FromIterator<TokenStream>` and
299/// `Extend<TokenStream>` with less monomorphization in calling crates.
300struct ConcatStreamsHelper {
301 streams: Vec<bridge::client::TokenStream>,
302}
303
304impl ConcatStreamsHelper {
305 fn new(capacity: usize) -> Self {
306 ConcatStreamsHelper { streams: Vec::with_capacity(capacity) }
307 }
308
309 fn push(&mut self, stream: TokenStream) {
310 if let Some(stream) = stream.0 {
311 self.streams.push(stream);
312 }
313 }
314
315 fn build(mut self) -> TokenStream {
316 if self.streams.len() <= 1 {
317 TokenStream(self.streams.pop())
318 } else {
319 TokenStream(Some(bridge::client::TokenStream::concat_streams(None, self.streams)))
320 }
321 }
322
323 fn append_to(mut self, stream: &mut TokenStream) {
324 if self.streams.is_empty() {
325 return;
326 }
327 let base = stream.0.take();
328 if base.is_none() && self.streams.len() == 1 {
329 stream.0 = self.streams.pop();
330 } else {
331 stream.0 = Some(bridge::client::TokenStream::concat_streams(base, self.streams));
332 }
333 }
334}
335
336/// Collects a number of token trees into a single stream.
337#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
338impl FromIterator<TokenTree> for TokenStream {
339 fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self {
340 let iter: ::IntoIter = trees.into_iter();
341 let mut builder: ConcatTreesHelper = ConcatTreesHelper::new(capacity:iter.size_hint().0);
342 iter.for_each(|tree: TokenTree| builder.push(tree));
343 builder.build()
344 }
345}
346
347/// A "flattening" operation on token streams, collects token trees
348/// from multiple token streams into a single stream.
349#[stable(feature = "proc_macro_lib", since = "1.15.0")]
350impl FromIterator<TokenStream> for TokenStream {
351 fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
352 let iter: ::IntoIter = streams.into_iter();
353 let mut builder: ConcatStreamsHelper = ConcatStreamsHelper::new(capacity:iter.size_hint().0);
354 iter.for_each(|stream: TokenStream| builder.push(stream));
355 builder.build()
356 }
357}
358
359#[stable(feature = "token_stream_extend", since = "1.30.0")]
360impl Extend<TokenTree> for TokenStream {
361 fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) {
362 let iter: ::IntoIter = trees.into_iter();
363 let mut builder: ConcatTreesHelper = ConcatTreesHelper::new(capacity:iter.size_hint().0);
364 iter.for_each(|tree: TokenTree| builder.push(tree));
365 builder.append_to(self);
366 }
367}
368
369#[stable(feature = "token_stream_extend", since = "1.30.0")]
370impl Extend<TokenStream> for TokenStream {
371 fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
372 let iter: ::IntoIter = streams.into_iter();
373 let mut builder: ConcatStreamsHelper = ConcatStreamsHelper::new(capacity:iter.size_hint().0);
374 iter.for_each(|stream: TokenStream| builder.push(stream));
375 builder.append_to(self);
376 }
377}
378
379/// Public implementation details for the `TokenStream` type, such as iterators.
380#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
381pub mod token_stream {
382 use crate::{Group, Ident, Literal, Punct, TokenStream, TokenTree, bridge};
383
384 /// An iterator over `TokenStream`'s `TokenTree`s.
385 /// The iteration is "shallow", e.g., the iterator doesn't recurse into delimited groups,
386 /// and returns whole groups as token trees.
387 #[derive(Clone)]
388 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
389 pub struct IntoIter(
390 std::vec::IntoIter<
391 bridge::TokenTree<
392 bridge::client::TokenStream,
393 bridge::client::Span,
394 bridge::client::Symbol,
395 >,
396 >,
397 );
398
399 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
400 impl Iterator for IntoIter {
401 type Item = TokenTree;
402
403 fn next(&mut self) -> Option<TokenTree> {
404 self.0.next().map(|tree| match tree {
405 bridge::TokenTree::Group(tt) => TokenTree::Group(Group(tt)),
406 bridge::TokenTree::Punct(tt) => TokenTree::Punct(Punct(tt)),
407 bridge::TokenTree::Ident(tt) => TokenTree::Ident(Ident(tt)),
408 bridge::TokenTree::Literal(tt) => TokenTree::Literal(Literal(tt)),
409 })
410 }
411
412 fn size_hint(&self) -> (usize, Option<usize>) {
413 self.0.size_hint()
414 }
415
416 fn count(self) -> usize {
417 self.0.count()
418 }
419 }
420
421 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
422 impl IntoIterator for TokenStream {
423 type Item = TokenTree;
424 type IntoIter = IntoIter;
425
426 fn into_iter(self) -> IntoIter {
427 IntoIter(self.0.map(|v| v.into_trees()).unwrap_or_default().into_iter())
428 }
429 }
430}
431
432/// `quote!(..)` accepts arbitrary tokens and expands into a `TokenStream` describing the input.
433/// For example, `quote!(a + b)` will produce an expression, that, when evaluated, constructs
434/// the `TokenStream` `[Ident("a"), Punct('+', Alone), Ident("b")]`.
435///
436/// Unquoting is done with `$`, and works by taking the single next ident as the unquoted term.
437/// To quote `$` itself, use `$$`.
438#[unstable(feature = "proc_macro_quote", issue = "54722")]
439#[allow_internal_unstable(proc_macro_def_site, proc_macro_internals, proc_macro_totokens)]
440#[rustc_builtin_macro]
441pub macro quote($($t:tt)*) {
442 /* compiler built-in */
443}
444
445#[unstable(feature = "proc_macro_internals", issue = "27812")]
446#[doc(hidden)]
447mod quote;
448
449/// A region of source code, along with macro expansion information.
450#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
451#[derive(Copy, Clone)]
452pub struct Span(bridge::client::Span);
453
454#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
455impl !Send for Span {}
456#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
457impl !Sync for Span {}
458
459macro_rules! diagnostic_method {
460 ($name:ident, $level:expr) => {
461 /// Creates a new `Diagnostic` with the given `message` at the span
462 /// `self`.
463 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
464 pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic {
465 Diagnostic::spanned(self, $level, message)
466 }
467 };
468}
469
470impl Span {
471 /// A span that resolves at the macro definition site.
472 #[unstable(feature = "proc_macro_def_site", issue = "54724")]
473 pub fn def_site() -> Span {
474 Span(bridge::client::Span::def_site())
475 }
476
477 /// The span of the invocation of the current procedural macro.
478 /// Identifiers created with this span will be resolved as if they were written
479 /// directly at the macro call location (call-site hygiene) and other code
480 /// at the macro call site will be able to refer to them as well.
481 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
482 pub fn call_site() -> Span {
483 Span(bridge::client::Span::call_site())
484 }
485
486 /// A span that represents `macro_rules` hygiene, and sometimes resolves at the macro
487 /// definition site (local variables, labels, `$crate`) and sometimes at the macro
488 /// call site (everything else).
489 /// The span location is taken from the call-site.
490 #[stable(feature = "proc_macro_mixed_site", since = "1.45.0")]
491 pub fn mixed_site() -> Span {
492 Span(bridge::client::Span::mixed_site())
493 }
494
495 /// The `Span` for the tokens in the previous macro expansion from which
496 /// `self` was generated from, if any.
497 #[unstable(feature = "proc_macro_span", issue = "54725")]
498 pub fn parent(&self) -> Option<Span> {
499 self.0.parent().map(Span)
500 }
501
502 /// The span for the origin source code that `self` was generated from. If
503 /// this `Span` wasn't generated from other macro expansions then the return
504 /// value is the same as `*self`.
505 #[unstable(feature = "proc_macro_span", issue = "54725")]
506 pub fn source(&self) -> Span {
507 Span(self.0.source())
508 }
509
510 /// Returns the span's byte position range in the source file.
511 #[unstable(feature = "proc_macro_span", issue = "54725")]
512 pub fn byte_range(&self) -> Range<usize> {
513 self.0.byte_range()
514 }
515
516 /// Creates an empty span pointing to directly before this span.
517 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
518 pub fn start(&self) -> Span {
519 Span(self.0.start())
520 }
521
522 /// Creates an empty span pointing to directly after this span.
523 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
524 pub fn end(&self) -> Span {
525 Span(self.0.end())
526 }
527
528 /// The one-indexed line of the source file where the span starts.
529 ///
530 /// To obtain the line of the span's end, use `span.end().line()`.
531 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
532 pub fn line(&self) -> usize {
533 self.0.line()
534 }
535
536 /// The one-indexed column of the source file where the span starts.
537 ///
538 /// To obtain the column of the span's end, use `span.end().column()`.
539 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
540 pub fn column(&self) -> usize {
541 self.0.column()
542 }
543
544 /// The path to the source file in which this span occurs, for display purposes.
545 ///
546 /// This might not correspond to a valid file system path.
547 /// It might be remapped (e.g. `"/src/lib.rs"`) or an artificial path (e.g. `"<command line>"`).
548 #[stable(feature = "proc_macro_span_file", since = "1.88.0")]
549 pub fn file(&self) -> String {
550 self.0.file()
551 }
552
553 /// The path to the source file in which this span occurs on the local file system.
554 ///
555 /// This is the actual path on disk. It is unaffected by path remapping.
556 ///
557 /// This path should not be embedded in the output of the macro; prefer `file()` instead.
558 #[stable(feature = "proc_macro_span_file", since = "1.88.0")]
559 pub fn local_file(&self) -> Option<PathBuf> {
560 self.0.local_file().map(|s| PathBuf::from(s))
561 }
562
563 /// Creates a new span encompassing `self` and `other`.
564 ///
565 /// Returns `None` if `self` and `other` are from different files.
566 #[unstable(feature = "proc_macro_span", issue = "54725")]
567 pub fn join(&self, other: Span) -> Option<Span> {
568 self.0.join(other.0).map(Span)
569 }
570
571 /// Creates a new span with the same line/column information as `self` but
572 /// that resolves symbols as though it were at `other`.
573 #[stable(feature = "proc_macro_span_resolved_at", since = "1.45.0")]
574 pub fn resolved_at(&self, other: Span) -> Span {
575 Span(self.0.resolved_at(other.0))
576 }
577
578 /// Creates a new span with the same name resolution behavior as `self` but
579 /// with the line/column information of `other`.
580 #[stable(feature = "proc_macro_span_located_at", since = "1.45.0")]
581 pub fn located_at(&self, other: Span) -> Span {
582 other.resolved_at(*self)
583 }
584
585 /// Compares two spans to see if they're equal.
586 #[unstable(feature = "proc_macro_span", issue = "54725")]
587 pub fn eq(&self, other: &Span) -> bool {
588 self.0 == other.0
589 }
590
591 /// Returns the source text behind a span. This preserves the original source
592 /// code, including spaces and comments. It only returns a result if the span
593 /// corresponds to real source code.
594 ///
595 /// Note: The observable result of a macro should only rely on the tokens and
596 /// not on this source text. The result of this function is a best effort to
597 /// be used for diagnostics only.
598 #[stable(feature = "proc_macro_source_text", since = "1.66.0")]
599 pub fn source_text(&self) -> Option<String> {
600 self.0.source_text()
601 }
602
603 // Used by the implementation of `Span::quote`
604 #[doc(hidden)]
605 #[unstable(feature = "proc_macro_internals", issue = "27812")]
606 pub fn save_span(&self) -> usize {
607 self.0.save_span()
608 }
609
610 // Used by the implementation of `Span::quote`
611 #[doc(hidden)]
612 #[unstable(feature = "proc_macro_internals", issue = "27812")]
613 pub fn recover_proc_macro_span(id: usize) -> Span {
614 Span(bridge::client::Span::recover_proc_macro_span(id))
615 }
616
617 diagnostic_method!(error, Level::Error);
618 diagnostic_method!(warning, Level::Warning);
619 diagnostic_method!(note, Level::Note);
620 diagnostic_method!(help, Level::Help);
621}
622
623/// Prints a span in a form convenient for debugging.
624#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
625impl fmt::Debug for Span {
626 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
627 self.0.fmt(f)
628 }
629}
630
631/// A single token or a delimited sequence of token trees (e.g., `[1, (), ..]`).
632#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
633#[derive(Clone)]
634pub enum TokenTree {
635 /// A token stream surrounded by bracket delimiters.
636 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
637 Group(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Group),
638 /// An identifier.
639 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
640 Ident(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Ident),
641 /// A single punctuation character (`+`, `,`, `$`, etc.).
642 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
643 Punct(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Punct),
644 /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
645 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
646 Literal(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Literal),
647}
648
649#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
650impl !Send for TokenTree {}
651#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
652impl !Sync for TokenTree {}
653
654impl TokenTree {
655 /// Returns the span of this tree, delegating to the `span` method of
656 /// the contained token or a delimited stream.
657 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
658 pub fn span(&self) -> Span {
659 match *self {
660 TokenTree::Group(ref t) => t.span(),
661 TokenTree::Ident(ref t) => t.span(),
662 TokenTree::Punct(ref t) => t.span(),
663 TokenTree::Literal(ref t) => t.span(),
664 }
665 }
666
667 /// Configures the span for *only this token*.
668 ///
669 /// Note that if this token is a `Group` then this method will not configure
670 /// the span of each of the internal tokens, this will simply delegate to
671 /// the `set_span` method of each variant.
672 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
673 pub fn set_span(&mut self, span: Span) {
674 match *self {
675 TokenTree::Group(ref mut t) => t.set_span(span),
676 TokenTree::Ident(ref mut t) => t.set_span(span),
677 TokenTree::Punct(ref mut t) => t.set_span(span),
678 TokenTree::Literal(ref mut t) => t.set_span(span),
679 }
680 }
681}
682
683/// Prints token tree in a form convenient for debugging.
684#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
685impl fmt::Debug for TokenTree {
686 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
687 // Each of these has the name in the struct type in the derived debug,
688 // so don't bother with an extra layer of indirection
689 match *self {
690 TokenTree::Group(ref tt: &Group) => tt.fmt(f),
691 TokenTree::Ident(ref tt: &Ident) => tt.fmt(f),
692 TokenTree::Punct(ref tt: &Punct) => tt.fmt(f),
693 TokenTree::Literal(ref tt: &Literal) => tt.fmt(f),
694 }
695 }
696}
697
698#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
699impl From<Group> for TokenTree {
700 fn from(g: Group) -> TokenTree {
701 TokenTree::Group(g)
702 }
703}
704
705#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
706impl From<Ident> for TokenTree {
707 fn from(g: Ident) -> TokenTree {
708 TokenTree::Ident(g)
709 }
710}
711
712#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
713impl From<Punct> for TokenTree {
714 fn from(g: Punct) -> TokenTree {
715 TokenTree::Punct(g)
716 }
717}
718
719#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
720impl From<Literal> for TokenTree {
721 fn from(g: Literal) -> TokenTree {
722 TokenTree::Literal(g)
723 }
724}
725
726/// Prints the token tree as a string that is supposed to be losslessly convertible back
727/// into the same token tree (modulo spans), except for possibly `TokenTree::Group`s
728/// with `Delimiter::None` delimiters and negative numeric literals.
729///
730/// Note: the exact form of the output is subject to change, e.g. there might
731/// be changes in the whitespace used between tokens. Therefore, you should
732/// *not* do any kind of simple substring matching on the output string (as
733/// produced by `to_string`) to implement a proc macro, because that matching
734/// might stop working if such changes happen. Instead, you should work at the
735/// `TokenTree` level, e.g. matching against `TokenTree::Ident`,
736/// `TokenTree::Punct`, or `TokenTree::Literal`.
737#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
738impl fmt::Display for TokenTree {
739 #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
740 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
741 match self {
742 TokenTree::Group(t: &Group) => write!(f, "{t}"),
743 TokenTree::Ident(t: &Ident) => write!(f, "{t}"),
744 TokenTree::Punct(t: &Punct) => write!(f, "{t}"),
745 TokenTree::Literal(t: &Literal) => write!(f, "{t}"),
746 }
747 }
748}
749
750/// A delimited token stream.
751///
752/// A `Group` internally contains a `TokenStream` which is surrounded by `Delimiter`s.
753#[derive(Clone)]
754#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
755pub struct Group(bridge::Group<bridge::client::TokenStream, bridge::client::Span>);
756
757#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
758impl !Send for Group {}
759#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
760impl !Sync for Group {}
761
762/// Describes how a sequence of token trees is delimited.
763#[derive(Copy, Clone, Debug, PartialEq, Eq)]
764#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
765pub enum Delimiter {
766 /// `( ... )`
767 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
768 Parenthesis,
769 /// `{ ... }`
770 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
771 Brace,
772 /// `[ ... ]`
773 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
774 Bracket,
775 /// `∅ ... ∅`
776 /// An invisible delimiter, that may, for example, appear around tokens coming from a
777 /// "macro variable" `$var`. It is important to preserve operator priorities in cases like
778 /// `$var * 3` where `$var` is `1 + 2`.
779 /// Invisible delimiters might not survive roundtrip of a token stream through a string.
780 ///
781 /// <div class="warning">
782 ///
783 /// Note: rustc currently can ignore the grouping of tokens delimited by `None` in the output
784 /// of a proc_macro. Only `None`-delimited groups created by a macro_rules macro in the input
785 /// of a proc_macro macro are preserved, and only in very specific circumstances.
786 /// Any `None`-delimited groups (re)created by a proc_macro will therefore not preserve
787 /// operator priorities as indicated above. The other `Delimiter` variants should be used
788 /// instead in this context. This is a rustc bug. For details, see
789 /// [rust-lang/rust#67062](https://github.com/rust-lang/rust/issues/67062).
790 ///
791 /// </div>
792 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
793 None,
794}
795
796impl Group {
797 /// Creates a new `Group` with the given delimiter and token stream.
798 ///
799 /// This constructor will set the span for this group to
800 /// `Span::call_site()`. To change the span you can use the `set_span`
801 /// method below.
802 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
803 pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group {
804 Group(bridge::Group {
805 delimiter,
806 stream: stream.0,
807 span: bridge::DelimSpan::from_single(Span::call_site().0),
808 })
809 }
810
811 /// Returns the delimiter of this `Group`
812 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
813 pub fn delimiter(&self) -> Delimiter {
814 self.0.delimiter
815 }
816
817 /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
818 ///
819 /// Note that the returned token stream does not include the delimiter
820 /// returned above.
821 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
822 pub fn stream(&self) -> TokenStream {
823 TokenStream(self.0.stream.clone())
824 }
825
826 /// Returns the span for the delimiters of this token stream, spanning the
827 /// entire `Group`.
828 ///
829 /// ```text
830 /// pub fn span(&self) -> Span {
831 /// ^^^^^^^
832 /// ```
833 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
834 pub fn span(&self) -> Span {
835 Span(self.0.span.entire)
836 }
837
838 /// Returns the span pointing to the opening delimiter of this group.
839 ///
840 /// ```text
841 /// pub fn span_open(&self) -> Span {
842 /// ^
843 /// ```
844 #[stable(feature = "proc_macro_group_span", since = "1.55.0")]
845 pub fn span_open(&self) -> Span {
846 Span(self.0.span.open)
847 }
848
849 /// Returns the span pointing to the closing delimiter of this group.
850 ///
851 /// ```text
852 /// pub fn span_close(&self) -> Span {
853 /// ^
854 /// ```
855 #[stable(feature = "proc_macro_group_span", since = "1.55.0")]
856 pub fn span_close(&self) -> Span {
857 Span(self.0.span.close)
858 }
859
860 /// Configures the span for this `Group`'s delimiters, but not its internal
861 /// tokens.
862 ///
863 /// This method will **not** set the span of all the internal tokens spanned
864 /// by this group, but rather it will only set the span of the delimiter
865 /// tokens at the level of the `Group`.
866 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
867 pub fn set_span(&mut self, span: Span) {
868 self.0.span = bridge::DelimSpan::from_single(span.0);
869 }
870}
871
872/// Prints the group as a string that should be losslessly convertible back
873/// into the same group (modulo spans), except for possibly `TokenTree::Group`s
874/// with `Delimiter::None` delimiters.
875#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
876impl fmt::Display for Group {
877 #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
878 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
879 write!(f, "{}", TokenStream::from(TokenTree::from(self.clone())))
880 }
881}
882
883#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
884impl fmt::Debug for Group {
885 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
886 f&mut DebugStruct<'_, '_>.debug_struct("Group")
887 .field("delimiter", &self.delimiter())
888 .field("stream", &self.stream())
889 .field(name:"span", &self.span())
890 .finish()
891 }
892}
893
894/// A `Punct` is a single punctuation character such as `+`, `-` or `#`.
895///
896/// Multi-character operators like `+=` are represented as two instances of `Punct` with different
897/// forms of `Spacing` returned.
898#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
899#[derive(Clone)]
900pub struct Punct(bridge::Punct<bridge::client::Span>);
901
902#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
903impl !Send for Punct {}
904#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
905impl !Sync for Punct {}
906
907/// Indicates whether a `Punct` token can join with the following token
908/// to form a multi-character operator.
909#[derive(Copy, Clone, Debug, PartialEq, Eq)]
910#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
911pub enum Spacing {
912 /// A `Punct` token can join with the following token to form a multi-character operator.
913 ///
914 /// In token streams constructed using proc macro interfaces, `Joint` punctuation tokens can be
915 /// followed by any other tokens. However, in token streams parsed from source code, the
916 /// compiler will only set spacing to `Joint` in the following cases.
917 /// - When a `Punct` is immediately followed by another `Punct` without a whitespace. E.g. `+`
918 /// is `Joint` in `+=` and `++`.
919 /// - When a single quote `'` is immediately followed by an identifier without a whitespace.
920 /// E.g. `'` is `Joint` in `'lifetime`.
921 ///
922 /// This list may be extended in the future to enable more token combinations.
923 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
924 Joint,
925 /// A `Punct` token cannot join with the following token to form a multi-character operator.
926 ///
927 /// `Alone` punctuation tokens can be followed by any other tokens. In token streams parsed
928 /// from source code, the compiler will set spacing to `Alone` in all cases not covered by the
929 /// conditions for `Joint` above. E.g. `+` is `Alone` in `+ =`, `+ident` and `+()`. In
930 /// particular, tokens not followed by anything will be marked as `Alone`.
931 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
932 Alone,
933}
934
935impl Punct {
936 /// Creates a new `Punct` from the given character and spacing.
937 /// The `ch` argument must be a valid punctuation character permitted by the language,
938 /// otherwise the function will panic.
939 ///
940 /// The returned `Punct` will have the default span of `Span::call_site()`
941 /// which can be further configured with the `set_span` method below.
942 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
943 pub fn new(ch: char, spacing: Spacing) -> Punct {
944 const LEGAL_CHARS: &[char] = &[
945 '=', '<', '>', '!', '~', '+', '-', '*', '/', '%', '^', '&', '|', '@', '.', ',', ';',
946 ':', '#', '$', '?', '\'',
947 ];
948 if !LEGAL_CHARS.contains(&ch) {
949 panic!("unsupported character `{:?}`", ch);
950 }
951 Punct(bridge::Punct {
952 ch: ch as u8,
953 joint: spacing == Spacing::Joint,
954 span: Span::call_site().0,
955 })
956 }
957
958 /// Returns the value of this punctuation character as `char`.
959 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
960 pub fn as_char(&self) -> char {
961 self.0.ch as char
962 }
963
964 /// Returns the spacing of this punctuation character, indicating whether it can be potentially
965 /// combined into a multi-character operator with the following token (`Joint`), or whether the
966 /// operator has definitely ended (`Alone`).
967 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
968 pub fn spacing(&self) -> Spacing {
969 if self.0.joint { Spacing::Joint } else { Spacing::Alone }
970 }
971
972 /// Returns the span for this punctuation character.
973 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
974 pub fn span(&self) -> Span {
975 Span(self.0.span)
976 }
977
978 /// Configure the span for this punctuation character.
979 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
980 pub fn set_span(&mut self, span: Span) {
981 self.0.span = span.0;
982 }
983}
984
985/// Prints the punctuation character as a string that should be losslessly convertible
986/// back into the same character.
987#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
988impl fmt::Display for Punct {
989 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
990 write!(f, "{}", self.as_char())
991 }
992}
993
994#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
995impl fmt::Debug for Punct {
996 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
997 f&mut DebugStruct<'_, '_>.debug_struct("Punct")
998 .field("ch", &self.as_char())
999 .field("spacing", &self.spacing())
1000 .field(name:"span", &self.span())
1001 .finish()
1002 }
1003}
1004
1005#[stable(feature = "proc_macro_punct_eq", since = "1.50.0")]
1006impl PartialEq<char> for Punct {
1007 fn eq(&self, rhs: &char) -> bool {
1008 self.as_char() == *rhs
1009 }
1010}
1011
1012#[stable(feature = "proc_macro_punct_eq_flipped", since = "1.52.0")]
1013impl PartialEq<Punct> for char {
1014 fn eq(&self, rhs: &Punct) -> bool {
1015 *self == rhs.as_char()
1016 }
1017}
1018
1019/// An identifier (`ident`).
1020#[derive(Clone)]
1021#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1022pub struct Ident(bridge::Ident<bridge::client::Span, bridge::client::Symbol>);
1023
1024impl Ident {
1025 /// Creates a new `Ident` with the given `string` as well as the specified
1026 /// `span`.
1027 /// The `string` argument must be a valid identifier permitted by the
1028 /// language (including keywords, e.g. `self` or `fn`). Otherwise, the function will panic.
1029 ///
1030 /// Note that `span`, currently in rustc, configures the hygiene information
1031 /// for this identifier.
1032 ///
1033 /// As of this time `Span::call_site()` explicitly opts-in to "call-site" hygiene
1034 /// meaning that identifiers created with this span will be resolved as if they were written
1035 /// directly at the location of the macro call, and other code at the macro call site will be
1036 /// able to refer to them as well.
1037 ///
1038 /// Later spans like `Span::def_site()` will allow to opt-in to "definition-site" hygiene
1039 /// meaning that identifiers created with this span will be resolved at the location of the
1040 /// macro definition and other code at the macro call site will not be able to refer to them.
1041 ///
1042 /// Due to the current importance of hygiene this constructor, unlike other
1043 /// tokens, requires a `Span` to be specified at construction.
1044 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1045 pub fn new(string: &str, span: Span) -> Ident {
1046 Ident(bridge::Ident {
1047 sym: bridge::client::Symbol::new_ident(string, false),
1048 is_raw: false,
1049 span: span.0,
1050 })
1051 }
1052
1053 /// Same as `Ident::new`, but creates a raw identifier (`r#ident`).
1054 /// The `string` argument be a valid identifier permitted by the language
1055 /// (including keywords, e.g. `fn`). Keywords which are usable in path segments
1056 /// (e.g. `self`, `super`) are not supported, and will cause a panic.
1057 #[stable(feature = "proc_macro_raw_ident", since = "1.47.0")]
1058 pub fn new_raw(string: &str, span: Span) -> Ident {
1059 Ident(bridge::Ident {
1060 sym: bridge::client::Symbol::new_ident(string, true),
1061 is_raw: true,
1062 span: span.0,
1063 })
1064 }
1065
1066 /// Returns the span of this `Ident`, encompassing the entire string returned
1067 /// by [`to_string`](ToString::to_string).
1068 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1069 pub fn span(&self) -> Span {
1070 Span(self.0.span)
1071 }
1072
1073 /// Configures the span of this `Ident`, possibly changing its hygiene context.
1074 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1075 pub fn set_span(&mut self, span: Span) {
1076 self.0.span = span.0;
1077 }
1078}
1079
1080/// Prints the identifier as a string that should be losslessly convertible back
1081/// into the same identifier.
1082#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1083impl fmt::Display for Ident {
1084 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1085 if self.0.is_raw {
1086 f.write_str(data:"r#")?;
1087 }
1088 fmt::Display::fmt(&self.0.sym, f)
1089 }
1090}
1091
1092#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1093impl fmt::Debug for Ident {
1094 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1095 f&mut DebugStruct<'_, '_>.debug_struct("Ident")
1096 .field("ident", &self.to_string())
1097 .field(name:"span", &self.span())
1098 .finish()
1099 }
1100}
1101
1102/// A literal string (`"hello"`), byte string (`b"hello"`), C string (`c"hello"`),
1103/// character (`'a'`), byte character (`b'a'`), an integer or floating point number
1104/// with or without a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
1105/// Boolean literals like `true` and `false` do not belong here, they are `Ident`s.
1106#[derive(Clone)]
1107#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1108pub struct Literal(bridge::Literal<bridge::client::Span, bridge::client::Symbol>);
1109
1110macro_rules! suffixed_int_literals {
1111 ($($name:ident => $kind:ident,)*) => ($(
1112 /// Creates a new suffixed integer literal with the specified value.
1113 ///
1114 /// This function will create an integer like `1u32` where the integer
1115 /// value specified is the first part of the token and the integral is
1116 /// also suffixed at the end.
1117 /// Literals created from negative numbers might not survive round-trips through
1118 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1119 ///
1120 /// Literals created through this method have the `Span::call_site()`
1121 /// span by default, which can be configured with the `set_span` method
1122 /// below.
1123 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1124 pub fn $name(n: $kind) -> Literal {
1125 Literal(bridge::Literal {
1126 kind: bridge::LitKind::Integer,
1127 symbol: bridge::client::Symbol::new(&n.to_string()),
1128 suffix: Some(bridge::client::Symbol::new(stringify!($kind))),
1129 span: Span::call_site().0,
1130 })
1131 }
1132 )*)
1133}
1134
1135macro_rules! unsuffixed_int_literals {
1136 ($($name:ident => $kind:ident,)*) => ($(
1137 /// Creates a new unsuffixed integer literal with the specified value.
1138 ///
1139 /// This function will create an integer like `1` where the integer
1140 /// value specified is the first part of the token. No suffix is
1141 /// specified on this token, meaning that invocations like
1142 /// `Literal::i8_unsuffixed(1)` are equivalent to
1143 /// `Literal::u32_unsuffixed(1)`.
1144 /// Literals created from negative numbers might not survive rountrips through
1145 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1146 ///
1147 /// Literals created through this method have the `Span::call_site()`
1148 /// span by default, which can be configured with the `set_span` method
1149 /// below.
1150 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1151 pub fn $name(n: $kind) -> Literal {
1152 Literal(bridge::Literal {
1153 kind: bridge::LitKind::Integer,
1154 symbol: bridge::client::Symbol::new(&n.to_string()),
1155 suffix: None,
1156 span: Span::call_site().0,
1157 })
1158 }
1159 )*)
1160}
1161
1162impl Literal {
1163 fn new(kind: bridge::LitKind, value: &str, suffix: Option<&str>) -> Self {
1164 Literal(bridge::Literal {
1165 kind,
1166 symbol: bridge::client::Symbol::new(value),
1167 suffix: suffix.map(bridge::client::Symbol::new),
1168 span: Span::call_site().0,
1169 })
1170 }
1171
1172 suffixed_int_literals! {
1173 u8_suffixed => u8,
1174 u16_suffixed => u16,
1175 u32_suffixed => u32,
1176 u64_suffixed => u64,
1177 u128_suffixed => u128,
1178 usize_suffixed => usize,
1179 i8_suffixed => i8,
1180 i16_suffixed => i16,
1181 i32_suffixed => i32,
1182 i64_suffixed => i64,
1183 i128_suffixed => i128,
1184 isize_suffixed => isize,
1185 }
1186
1187 unsuffixed_int_literals! {
1188 u8_unsuffixed => u8,
1189 u16_unsuffixed => u16,
1190 u32_unsuffixed => u32,
1191 u64_unsuffixed => u64,
1192 u128_unsuffixed => u128,
1193 usize_unsuffixed => usize,
1194 i8_unsuffixed => i8,
1195 i16_unsuffixed => i16,
1196 i32_unsuffixed => i32,
1197 i64_unsuffixed => i64,
1198 i128_unsuffixed => i128,
1199 isize_unsuffixed => isize,
1200 }
1201
1202 /// Creates a new unsuffixed floating-point literal.
1203 ///
1204 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1205 /// the float's value is emitted directly into the token but no suffix is
1206 /// used, so it may be inferred to be a `f64` later in the compiler.
1207 /// Literals created from negative numbers might not survive rountrips through
1208 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1209 ///
1210 /// # Panics
1211 ///
1212 /// This function requires that the specified float is finite, for
1213 /// example if it is infinity or NaN this function will panic.
1214 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1215 pub fn f32_unsuffixed(n: f32) -> Literal {
1216 if !n.is_finite() {
1217 panic!("Invalid float literal {n}");
1218 }
1219 let mut repr = n.to_string();
1220 if !repr.contains('.') {
1221 repr.push_str(".0");
1222 }
1223 Literal::new(bridge::LitKind::Float, &repr, None)
1224 }
1225
1226 /// Creates a new suffixed floating-point literal.
1227 ///
1228 /// This constructor will create a literal like `1.0f32` where the value
1229 /// specified is the preceding part of the token and `f32` is the suffix of
1230 /// the token. This token will always be inferred to be an `f32` in the
1231 /// compiler.
1232 /// Literals created from negative numbers might not survive rountrips through
1233 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1234 ///
1235 /// # Panics
1236 ///
1237 /// This function requires that the specified float is finite, for
1238 /// example if it is infinity or NaN this function will panic.
1239 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1240 pub fn f32_suffixed(n: f32) -> Literal {
1241 if !n.is_finite() {
1242 panic!("Invalid float literal {n}");
1243 }
1244 Literal::new(bridge::LitKind::Float, &n.to_string(), Some("f32"))
1245 }
1246
1247 /// Creates a new unsuffixed floating-point literal.
1248 ///
1249 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1250 /// the float's value is emitted directly into the token but no suffix is
1251 /// used, so it may be inferred to be a `f64` later in the compiler.
1252 /// Literals created from negative numbers might not survive rountrips through
1253 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1254 ///
1255 /// # Panics
1256 ///
1257 /// This function requires that the specified float is finite, for
1258 /// example if it is infinity or NaN this function will panic.
1259 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1260 pub fn f64_unsuffixed(n: f64) -> Literal {
1261 if !n.is_finite() {
1262 panic!("Invalid float literal {n}");
1263 }
1264 let mut repr = n.to_string();
1265 if !repr.contains('.') {
1266 repr.push_str(".0");
1267 }
1268 Literal::new(bridge::LitKind::Float, &repr, None)
1269 }
1270
1271 /// Creates a new suffixed floating-point literal.
1272 ///
1273 /// This constructor will create a literal like `1.0f64` where the value
1274 /// specified is the preceding part of the token and `f64` is the suffix of
1275 /// the token. This token will always be inferred to be an `f64` in the
1276 /// compiler.
1277 /// Literals created from negative numbers might not survive rountrips through
1278 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1279 ///
1280 /// # Panics
1281 ///
1282 /// This function requires that the specified float is finite, for
1283 /// example if it is infinity or NaN this function will panic.
1284 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1285 pub fn f64_suffixed(n: f64) -> Literal {
1286 if !n.is_finite() {
1287 panic!("Invalid float literal {n}");
1288 }
1289 Literal::new(bridge::LitKind::Float, &n.to_string(), Some("f64"))
1290 }
1291
1292 /// String literal.
1293 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1294 pub fn string(string: &str) -> Literal {
1295 let escape = EscapeOptions {
1296 escape_single_quote: false,
1297 escape_double_quote: true,
1298 escape_nonascii: false,
1299 };
1300 let repr = escape_bytes(string.as_bytes(), escape);
1301 Literal::new(bridge::LitKind::Str, &repr, None)
1302 }
1303
1304 /// Character literal.
1305 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1306 pub fn character(ch: char) -> Literal {
1307 let escape = EscapeOptions {
1308 escape_single_quote: true,
1309 escape_double_quote: false,
1310 escape_nonascii: false,
1311 };
1312 let repr = escape_bytes(ch.encode_utf8(&mut [0u8; 4]).as_bytes(), escape);
1313 Literal::new(bridge::LitKind::Char, &repr, None)
1314 }
1315
1316 /// Byte character literal.
1317 #[stable(feature = "proc_macro_byte_character", since = "1.79.0")]
1318 pub fn byte_character(byte: u8) -> Literal {
1319 let escape = EscapeOptions {
1320 escape_single_quote: true,
1321 escape_double_quote: false,
1322 escape_nonascii: true,
1323 };
1324 let repr = escape_bytes(&[byte], escape);
1325 Literal::new(bridge::LitKind::Byte, &repr, None)
1326 }
1327
1328 /// Byte string literal.
1329 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1330 pub fn byte_string(bytes: &[u8]) -> Literal {
1331 let escape = EscapeOptions {
1332 escape_single_quote: false,
1333 escape_double_quote: true,
1334 escape_nonascii: true,
1335 };
1336 let repr = escape_bytes(bytes, escape);
1337 Literal::new(bridge::LitKind::ByteStr, &repr, None)
1338 }
1339
1340 /// C string literal.
1341 #[stable(feature = "proc_macro_c_str_literals", since = "1.79.0")]
1342 pub fn c_string(string: &CStr) -> Literal {
1343 let escape = EscapeOptions {
1344 escape_single_quote: false,
1345 escape_double_quote: true,
1346 escape_nonascii: false,
1347 };
1348 let repr = escape_bytes(string.to_bytes(), escape);
1349 Literal::new(bridge::LitKind::CStr, &repr, None)
1350 }
1351
1352 /// Returns the span encompassing this literal.
1353 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1354 pub fn span(&self) -> Span {
1355 Span(self.0.span)
1356 }
1357
1358 /// Configures the span associated for this literal.
1359 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1360 pub fn set_span(&mut self, span: Span) {
1361 self.0.span = span.0;
1362 }
1363
1364 /// Returns a `Span` that is a subset of `self.span()` containing only the
1365 /// source bytes in range `range`. Returns `None` if the would-be trimmed
1366 /// span is outside the bounds of `self`.
1367 // FIXME(SergioBenitez): check that the byte range starts and ends at a
1368 // UTF-8 boundary of the source. otherwise, it's likely that a panic will
1369 // occur elsewhere when the source text is printed.
1370 // FIXME(SergioBenitez): there is no way for the user to know what
1371 // `self.span()` actually maps to, so this method can currently only be
1372 // called blindly. For example, `to_string()` for the character 'c' returns
1373 // "'\u{63}'"; there is no way for the user to know whether the source text
1374 // was 'c' or whether it was '\u{63}'.
1375 #[unstable(feature = "proc_macro_span", issue = "54725")]
1376 pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
1377 self.0.span.subspan(range.start_bound().cloned(), range.end_bound().cloned()).map(Span)
1378 }
1379
1380 fn with_symbol_and_suffix<R>(&self, f: impl FnOnce(&str, &str) -> R) -> R {
1381 self.0.symbol.with(|symbol| match self.0.suffix {
1382 Some(suffix) => suffix.with(|suffix| f(symbol, suffix)),
1383 None => f(symbol, ""),
1384 })
1385 }
1386
1387 /// Invokes the callback with a `&[&str]` consisting of each part of the
1388 /// literal's representation. This is done to allow the `ToString` and
1389 /// `Display` implementations to borrow references to symbol values, and
1390 /// both be optimized to reduce overhead.
1391 fn with_stringify_parts<R>(&self, f: impl FnOnce(&[&str]) -> R) -> R {
1392 /// Returns a string containing exactly `num` '#' characters.
1393 /// Uses a 256-character source string literal which is always safe to
1394 /// index with a `u8` index.
1395 fn get_hashes_str(num: u8) -> &'static str {
1396 const HASHES: &str = "\
1397 ################################################################\
1398 ################################################################\
1399 ################################################################\
1400 ################################################################\
1401 ";
1402 const _: () = assert!(HASHES.len() == 256);
1403 &HASHES[..num as usize]
1404 }
1405
1406 self.with_symbol_and_suffix(|symbol, suffix| match self.0.kind {
1407 bridge::LitKind::Byte => f(&["b'", symbol, "'", suffix]),
1408 bridge::LitKind::Char => f(&["'", symbol, "'", suffix]),
1409 bridge::LitKind::Str => f(&["\"", symbol, "\"", suffix]),
1410 bridge::LitKind::StrRaw(n) => {
1411 let hashes = get_hashes_str(n);
1412 f(&["r", hashes, "\"", symbol, "\"", hashes, suffix])
1413 }
1414 bridge::LitKind::ByteStr => f(&["b\"", symbol, "\"", suffix]),
1415 bridge::LitKind::ByteStrRaw(n) => {
1416 let hashes = get_hashes_str(n);
1417 f(&["br", hashes, "\"", symbol, "\"", hashes, suffix])
1418 }
1419 bridge::LitKind::CStr => f(&["c\"", symbol, "\"", suffix]),
1420 bridge::LitKind::CStrRaw(n) => {
1421 let hashes = get_hashes_str(n);
1422 f(&["cr", hashes, "\"", symbol, "\"", hashes, suffix])
1423 }
1424
1425 bridge::LitKind::Integer | bridge::LitKind::Float | bridge::LitKind::ErrWithGuar => {
1426 f(&[symbol, suffix])
1427 }
1428 })
1429 }
1430
1431 /// Returns the unescaped string value if the current literal is a string or a string literal.
1432 #[unstable(feature = "proc_macro_value", issue = "136652")]
1433 pub fn str_value(&self) -> Result<String, ConversionErrorKind> {
1434 self.0.symbol.with(|symbol| match self.0.kind {
1435 bridge::LitKind::Str => {
1436 if symbol.contains('\\') {
1437 let mut buf = String::with_capacity(symbol.len());
1438 let mut error = None;
1439 // Force-inlining here is aggressive but the closure is
1440 // called on every char in the string, so it can be hot in
1441 // programs with many long strings containing escapes.
1442 unescape_unicode(
1443 symbol,
1444 Mode::Str,
1445 &mut #[inline(always)]
1446 |_, c| match c {
1447 Ok(c) => buf.push(c),
1448 Err(err) => {
1449 if err.is_fatal() {
1450 error = Some(ConversionErrorKind::FailedToUnescape(err));
1451 }
1452 }
1453 },
1454 );
1455 if let Some(error) = error { Err(error) } else { Ok(buf) }
1456 } else {
1457 Ok(symbol.to_string())
1458 }
1459 }
1460 bridge::LitKind::StrRaw(_) => Ok(symbol.to_string()),
1461 _ => Err(ConversionErrorKind::InvalidLiteralKind),
1462 })
1463 }
1464
1465 /// Returns the unescaped string value if the current literal is a c-string or a c-string
1466 /// literal.
1467 #[unstable(feature = "proc_macro_value", issue = "136652")]
1468 pub fn cstr_value(&self) -> Result<Vec<u8>, ConversionErrorKind> {
1469 self.0.symbol.with(|symbol| match self.0.kind {
1470 bridge::LitKind::CStr => {
1471 let mut error = None;
1472 let mut buf = Vec::with_capacity(symbol.len());
1473
1474 unescape_mixed(symbol, Mode::CStr, &mut |_span, c| match c {
1475 Ok(MixedUnit::Char(c)) => {
1476 buf.extend_from_slice(c.encode_utf8(&mut [0; 4]).as_bytes())
1477 }
1478 Ok(MixedUnit::HighByte(b)) => buf.push(b),
1479 Err(err) => {
1480 if err.is_fatal() {
1481 error = Some(ConversionErrorKind::FailedToUnescape(err));
1482 }
1483 }
1484 });
1485 if let Some(error) = error {
1486 Err(error)
1487 } else {
1488 buf.push(0);
1489 Ok(buf)
1490 }
1491 }
1492 bridge::LitKind::CStrRaw(_) => {
1493 // Raw strings have no escapes so we can convert the symbol
1494 // directly to a `Lrc<u8>` after appending the terminating NUL
1495 // char.
1496 let mut buf = symbol.to_owned().into_bytes();
1497 buf.push(0);
1498 Ok(buf)
1499 }
1500 _ => Err(ConversionErrorKind::InvalidLiteralKind),
1501 })
1502 }
1503
1504 /// Returns the unescaped string value if the current literal is a byte string or a byte string
1505 /// literal.
1506 #[unstable(feature = "proc_macro_value", issue = "136652")]
1507 pub fn byte_str_value(&self) -> Result<Vec<u8>, ConversionErrorKind> {
1508 self.0.symbol.with(|symbol| match self.0.kind {
1509 bridge::LitKind::ByteStr => {
1510 let mut buf = Vec::with_capacity(symbol.len());
1511 let mut error = None;
1512
1513 unescape_unicode(symbol, Mode::ByteStr, &mut |_, c| match c {
1514 Ok(c) => buf.push(byte_from_char(c)),
1515 Err(err) => {
1516 if err.is_fatal() {
1517 error = Some(ConversionErrorKind::FailedToUnescape(err));
1518 }
1519 }
1520 });
1521 if let Some(error) = error { Err(error) } else { Ok(buf) }
1522 }
1523 bridge::LitKind::ByteStrRaw(_) => {
1524 // Raw strings have no escapes so we can convert the symbol
1525 // directly to a `Lrc<u8>`.
1526 Ok(symbol.to_owned().into_bytes())
1527 }
1528 _ => Err(ConversionErrorKind::InvalidLiteralKind),
1529 })
1530 }
1531}
1532
1533/// Parse a single literal from its stringified representation.
1534///
1535/// In order to parse successfully, the input string must not contain anything
1536/// but the literal token. Specifically, it must not contain whitespace or
1537/// comments in addition to the literal.
1538///
1539/// The resulting literal token will have a `Span::call_site()` span.
1540///
1541/// NOTE: some errors may cause panics instead of returning `LexError`. We
1542/// reserve the right to change these errors into `LexError`s later.
1543#[stable(feature = "proc_macro_literal_parse", since = "1.54.0")]
1544impl FromStr for Literal {
1545 type Err = LexError;
1546
1547 fn from_str(src: &str) -> Result<Self, LexError> {
1548 match bridge::client::FreeFunctions::literal_from_str(src) {
1549 Ok(literal: Literal) => Ok(Literal(literal)),
1550 Err(()) => Err(LexError),
1551 }
1552 }
1553}
1554
1555/// Prints the literal as a string that should be losslessly convertible
1556/// back into the same literal (except for possible rounding for floating point literals).
1557#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1558impl fmt::Display for Literal {
1559 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1560 self.with_stringify_parts(|parts: &[&str]| {
1561 for part: &&str in parts {
1562 fmt::Display::fmt(self:part, f)?;
1563 }
1564 Ok(())
1565 })
1566 }
1567}
1568
1569#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1570impl fmt::Debug for Literal {
1571 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1572 f&mut DebugStruct<'_, '_>.debug_struct("Literal")
1573 // format the kind on one line even in {:#?} mode
1574 .field("kind", &format_args!("{:?}", self.0.kind))
1575 .field("symbol", &self.0.symbol)
1576 // format `Some("...")` on one line even in {:#?} mode
1577 .field("suffix", &format_args!("{:?}", self.0.suffix))
1578 .field(name:"span", &self.0.span)
1579 .finish()
1580 }
1581}
1582
1583/// Tracked access to environment variables.
1584#[unstable(feature = "proc_macro_tracked_env", issue = "99515")]
1585pub mod tracked_env {
1586 use std::env::{self, VarError};
1587 use std::ffi::OsStr;
1588
1589 /// Retrieve an environment variable and add it to build dependency info.
1590 /// The build system executing the compiler will know that the variable was accessed during
1591 /// compilation, and will be able to rerun the build when the value of that variable changes.
1592 /// Besides the dependency tracking this function should be equivalent to `env::var` from the
1593 /// standard library, except that the argument must be UTF-8.
1594 #[unstable(feature = "proc_macro_tracked_env", issue = "99515")]
1595 pub fn var<K: AsRef<OsStr> + AsRef<str>>(key: K) -> Result<String, VarError> {
1596 let key: &str = key.as_ref();
1597 let value: Result = crate::bridge::client::FreeFunctions::injected_env_var(key)
1598 .map_or_else(|| env::var(key), f:Ok);
1599 crate::bridge::client::FreeFunctions::track_env_var(var:key, value.as_deref().ok());
1600 value
1601 }
1602}
1603
1604/// Tracked access to additional files.
1605#[unstable(feature = "track_path", issue = "99515")]
1606pub mod tracked_path {
1607
1608 /// Track a file explicitly.
1609 ///
1610 /// Commonly used for tracking asset preprocessing.
1611 #[unstable(feature = "track_path", issue = "99515")]
1612 pub fn path<P: AsRef<str>>(path: P) {
1613 let path: &str = path.as_ref();
1614 crate::bridge::client::FreeFunctions::track_path(path);
1615 }
1616}
1617