lib.rs - source (original) (raw)
proc_macro/
lib.rs
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#![warn(rustdoc::unescaped_backticks)]
36#![warn(unreachable_pub)]
37#![deny(unsafe_op_in_unsafe_fn)]
38
39#[unstable(feature = "proc_macro_internals", issue = "27812")]
40#[doc(hidden)]
41pub mod bridge;
42
43mod diagnostic;
44mod escape;
45mod to_tokens;
46
47use std::ffi::CStr;
48use std::ops::{Range, RangeBounds};
49use std::path::PathBuf;
50use std::str::FromStr;
51use std::{error, fmt};
52
53#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
54pub use diagnostic::{Diagnostic, Level, MultiSpan};
55#[unstable(feature = "proc_macro_value", issue = "136652")]
56pub use rustc_literal_escaper::EscapeError;
57use rustc_literal_escaper::{MixedUnit, Mode, byte_from_char, unescape_mixed, unescape_unicode};
58#[unstable(feature = "proc_macro_totokens", issue = "130977")]
59pub use to_tokens::ToTokens;
60
61use crate::escape::{EscapeOptions, escape_bytes};
62
63/// Errors returned when trying to retrieve a literal unescaped value.
64#[unstable(feature = "proc_macro_value", issue = "136652")]
65#[derive(Debug, PartialEq, Eq)]
66pub enum ConversionErrorKind {
67 /// The literal failed to be escaped, take a look at [`EscapeError`] for more information.
68 FailedToUnescape(EscapeError),
69 /// Trying to convert a literal with the wrong type.
70 InvalidLiteralKind,
71}
72
73/// Determines whether proc_macro has been made accessible to the currently
74/// running program.
75///
76/// The proc_macro crate is only intended for use inside the implementation of
77/// procedural macros. All the functions in this crate panic if invoked from
78/// outside of a procedural macro, such as from a build script or unit test or
79/// ordinary Rust binary.
80///
81/// With consideration for Rust libraries that are designed to support both
82/// macro and non-macro use cases, `proc_macro::is_available()` provides a
83/// non-panicking way to detect whether the infrastructure required to use the
84/// API of proc_macro is presently available. Returns true if invoked from
85/// inside of a procedural macro, false if invoked from any other binary.
86#[stable(feature = "proc_macro_is_available", since = "1.57.0")]
87pub fn is_available() -> bool {
88 bridge::client::is_available()
89}
90
91/// The main type provided by this crate, representing an abstract stream of
92/// tokens, or, more specifically, a sequence of token trees.
93/// The type provides interfaces for iterating over those token trees and, conversely,
94/// collecting a number of token trees into one stream.
95///
96/// This is both the input and output of `#[proc_macro]`, `#[proc_macro_attribute]`
97/// and `#[proc_macro_derive]` definitions.
98#[rustc_diagnostic_item = "TokenStream"]
99#[stable(feature = "proc_macro_lib", since = "1.15.0")]
100#[derive(Clone)]
101pub struct TokenStream(Option<bridge::client::TokenStream>);
102
103#[stable(feature = "proc_macro_lib", since = "1.15.0")]
104impl !Send for TokenStream {}
105#[stable(feature = "proc_macro_lib", since = "1.15.0")]
106impl !Sync for TokenStream {}
107
108/// Error returned from `TokenStream::from_str`.
109#[stable(feature = "proc_macro_lib", since = "1.15.0")]
110#[non_exhaustive]
111#[derive(Debug)]
112pub struct LexError;
113
114#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
115impl fmt::Display for LexError {
116 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
117 f.write_str("cannot parse string into token stream")
118 }
119}
120
121#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
122impl error::Error for LexError {}
123
124#[stable(feature = "proc_macro_lib", since = "1.15.0")]
125impl !Send for LexError {}
126#[stable(feature = "proc_macro_lib", since = "1.15.0")]
127impl !Sync for LexError {}
128
129/// Error returned from `TokenStream::expand_expr`.
130#[unstable(feature = "proc_macro_expand", issue = "90765")]
131#[non_exhaustive]
132#[derive(Debug)]
133pub struct ExpandError;
134
135#[unstable(feature = "proc_macro_expand", issue = "90765")]
136impl fmt::Display for ExpandError {
137 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
138 f.write_str("macro expansion failed")
139 }
140}
141
142#[unstable(feature = "proc_macro_expand", issue = "90765")]
143impl error::Error for ExpandError {}
144
145#[unstable(feature = "proc_macro_expand", issue = "90765")]
146impl !Send for ExpandError {}
147
148#[unstable(feature = "proc_macro_expand", issue = "90765")]
149impl !Sync for ExpandError {}
150
151impl TokenStream {
152 /// Returns an empty `TokenStream` containing no token trees.
153 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
154 pub fn new() -> TokenStream {
155 TokenStream(None)
156 }
157
158 /// Checks if this `TokenStream` is empty.
159 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
160 pub fn is_empty(&self) -> bool {
161 self.0.as_ref().map(|h| h.is_empty()).unwrap_or(true)
162 }
163
164 /// Parses this `TokenStream` as an expression and attempts to expand any
165 /// macros within it. Returns the expanded `TokenStream`.
166 ///
167 /// Currently only expressions expanding to literals will succeed, although
168 /// this may be relaxed in the future.
169 ///
170 /// NOTE: In error conditions, `expand_expr` may leave macros unexpanded,
171 /// report an error, failing compilation, and/or return an `Err(..)`. The
172 /// specific behavior for any error condition, and what conditions are
173 /// considered errors, is unspecified and may change in the future.
174 #[unstable(feature = "proc_macro_expand", issue = "90765")]
175 pub fn expand_expr(&self) -> Result<TokenStream, ExpandError> {
176 let stream = self.0.as_ref().ok_or(ExpandError)?;
177 match bridge::client::TokenStream::expand_expr(stream) {
178 Ok(stream) => Ok(TokenStream(Some(stream))),
179 Err(_) => Err(ExpandError),
180 }
181 }
182}
183
184/// Attempts to break the string into tokens and parse those tokens into a token stream.
185/// May fail for a number of reasons, for example, if the string contains unbalanced delimiters
186/// or characters not existing in the language.
187/// All tokens in the parsed stream get `Span::call_site()` spans.
188///
189/// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to
190/// change these errors into `LexError`s later.
191#[stable(feature = "proc_macro_lib", since = "1.15.0")]
192impl FromStr for TokenStream {
193 type Err = LexError;
194
195 fn from_str(src: &str) -> Result<TokenStream, LexError> {
196 Ok(TokenStream(Some(bridge::client::TokenStream::from_str(src))))
197 }
198}
199
200/// Prints the token stream as a string that is supposed to be losslessly convertible back
201/// into the same token stream (modulo spans), except for possibly `TokenTree::Group`s
202/// with `Delimiter::None` delimiters and negative numeric literals.
203///
204/// Note: the exact form of the output is subject to change, e.g. there might
205/// be changes in the whitespace used between tokens. Therefore, you should
206/// *not* do any kind of simple substring matching on the output string (as
207/// produced by `to_string`) to implement a proc macro, because that matching
208/// might stop working if such changes happen. Instead, you should work at the
209/// `TokenTree` level, e.g. matching against `TokenTree::Ident`,
210/// `TokenTree::Punct`, or `TokenTree::Literal`.
211#[stable(feature = "proc_macro_lib", since = "1.15.0")]
212impl fmt::Display for TokenStream {
213 #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
214 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
215 match &self.0 {
216 Some(ts) => write!(f, "{}", ts.to_string()),
217 None => Ok(()),
218 }
219 }
220}
221
222/// Prints token in a form convenient for debugging.
223#[stable(feature = "proc_macro_lib", since = "1.15.0")]
224impl fmt::Debug for TokenStream {
225 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
226 f.write_str("TokenStream ")?;
227 f.debug_list().entries(self.clone()).finish()
228 }
229}
230
231#[stable(feature = "proc_macro_token_stream_default", since = "1.45.0")]
232impl Default for TokenStream {
233 fn default() -> Self {
234 TokenStream::new()
235 }
236}
237
238#[unstable(feature = "proc_macro_quote", issue = "54722")]
239pub use quote::{quote, quote_span};
240
241fn tree_to_bridge_tree(
242 tree: TokenTree,
243) -> bridge::TokenTree<bridge::client::TokenStream, bridge::client::Span, bridge::client::Symbol> {
244 match tree {
245 TokenTree::Group(tt) => bridge::TokenTree::Group(tt.0),
246 TokenTree::Punct(tt) => bridge::TokenTree::Punct(tt.0),
247 TokenTree::Ident(tt) => bridge::TokenTree::Ident(tt.0),
248 TokenTree::Literal(tt) => bridge::TokenTree::Literal(tt.0),
249 }
250}
251
252/// Creates a token stream containing a single token tree.
253#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
254impl From<TokenTree> for TokenStream {
255 fn from(tree: TokenTree) -> TokenStream {
256 TokenStream(Some(bridge::client::TokenStream::from_token_tree(tree_to_bridge_tree(tree))))
257 }
258}
259
260/// Non-generic helper for implementing `FromIterator<TokenTree>` and
261/// `Extend<TokenTree>` with less monomorphization in calling crates.
262struct ConcatTreesHelper {
263 trees: Vec<
264 bridge::TokenTree<
265 bridge::client::TokenStream,
266 bridge::client::Span,
267 bridge::client::Symbol,
268 >,
269 >,
270}
271
272impl ConcatTreesHelper {
273 fn new(capacity: usize) -> Self {
274 ConcatTreesHelper { trees: Vec::with_capacity(capacity) }
275 }
276
277 fn push(&mut self, tree: TokenTree) {
278 self.trees.push(tree_to_bridge_tree(tree));
279 }
280
281 fn build(self) -> TokenStream {
282 if self.trees.is_empty() {
283 TokenStream(None)
284 } else {
285 TokenStream(Some(bridge::client::TokenStream::concat_trees(None, self.trees)))
286 }
287 }
288
289 fn append_to(self, stream: &mut TokenStream) {
290 if self.trees.is_empty() {
291 return;
292 }
293 stream.0 = Some(bridge::client::TokenStream::concat_trees(stream.0.take(), self.trees))
294 }
295}
296
297/// Non-generic helper for implementing `FromIterator<TokenStream>` and
298/// `Extend<TokenStream>` with less monomorphization in calling crates.
299struct ConcatStreamsHelper {
300 streams: Vec<bridge::client::TokenStream>,
301}
302
303impl ConcatStreamsHelper {
304 fn new(capacity: usize) -> Self {
305 ConcatStreamsHelper { streams: Vec::with_capacity(capacity) }
306 }
307
308 fn push(&mut self, stream: TokenStream) {
309 if let Some(stream) = stream.0 {
310 self.streams.push(stream);
311 }
312 }
313
314 fn build(mut self) -> TokenStream {
315 if self.streams.len() <= 1 {
316 TokenStream(self.streams.pop())
317 } else {
318 TokenStream(Some(bridge::client::TokenStream::concat_streams(None, self.streams)))
319 }
320 }
321
322 fn append_to(mut self, stream: &mut TokenStream) {
323 if self.streams.is_empty() {
324 return;
325 }
326 let base = stream.0.take();
327 if base.is_none() && self.streams.len() == 1 {
328 stream.0 = self.streams.pop();
329 } else {
330 stream.0 = Some(bridge::client::TokenStream::concat_streams(base, self.streams));
331 }
332 }
333}
334
335/// Collects a number of token trees into a single stream.
336#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
337impl FromIterator<TokenTree> for TokenStream {
338 fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self {
339 let iter = trees.into_iter();
340 let mut builder = ConcatTreesHelper::new(iter.size_hint().0);
341 iter.for_each(|tree| builder.push(tree));
342 builder.build()
343 }
344}
345
346/// A "flattening" operation on token streams, collects token trees
347/// from multiple token streams into a single stream.
348#[stable(feature = "proc_macro_lib", since = "1.15.0")]
349impl FromIterator<TokenStream> for TokenStream {
350 fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
351 let iter = streams.into_iter();
352 let mut builder = ConcatStreamsHelper::new(iter.size_hint().0);
353 iter.for_each(|stream| builder.push(stream));
354 builder.build()
355 }
356}
357
358#[stable(feature = "token_stream_extend", since = "1.30.0")]
359impl Extend<TokenTree> for TokenStream {
360 fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) {
361 let iter = trees.into_iter();
362 let mut builder = ConcatTreesHelper::new(iter.size_hint().0);
363 iter.for_each(|tree| builder.push(tree));
364 builder.append_to(self);
365 }
366}
367
368#[stable(feature = "token_stream_extend", since = "1.30.0")]
369impl Extend<TokenStream> for TokenStream {
370 fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
371 let iter = streams.into_iter();
372 let mut builder = ConcatStreamsHelper::new(iter.size_hint().0);
373 iter.for_each(|stream| builder.push(stream));
374 builder.append_to(self);
375 }
376}
377
378/// Public implementation details for the `TokenStream` type, such as iterators.
379#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
380pub mod token_stream {
381 use crate::{Group, Ident, Literal, Punct, TokenStream, TokenTree, bridge};
382
383 /// An iterator over `TokenStream`'s `TokenTree`s.
384 /// The iteration is "shallow", e.g., the iterator doesn't recurse into delimited groups,
385 /// and returns whole groups as token trees.
386 #[derive(Clone)]
387 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
388 pub struct IntoIter(
389 std::vec::IntoIter<
390 bridge::TokenTree<
391 bridge::client::TokenStream,
392 bridge::client::Span,
393 bridge::client::Symbol,
394 >,
395 >,
396 );
397
398 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
399 impl Iterator for IntoIter {
400 type Item = TokenTree;
401
402 fn next(&mut self) -> Option<TokenTree> {
403 self.0.next().map(|tree| match tree {
404 bridge::TokenTree::Group(tt) => TokenTree::Group(Group(tt)),
405 bridge::TokenTree::Punct(tt) => TokenTree::Punct(Punct(tt)),
406 bridge::TokenTree::Ident(tt) => TokenTree::Ident(Ident(tt)),
407 bridge::TokenTree::Literal(tt) => TokenTree::Literal(Literal(tt)),
408 })
409 }
410
411 fn size_hint(&self) -> (usize, Option<usize>) {
412 self.0.size_hint()
413 }
414
415 fn count(self) -> usize {
416 self.0.count()
417 }
418 }
419
420 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
421 impl IntoIterator for TokenStream {
422 type Item = TokenTree;
423 type IntoIter = IntoIter;
424
425 fn into_iter(self) -> IntoIter {
426 IntoIter(self.0.map(|v| v.into_trees()).unwrap_or_default().into_iter())
427 }
428 }
429}
430
431/// `quote!(..)` accepts arbitrary tokens and expands into a `TokenStream` describing the input.
432/// For example, `quote!(a + b)` will produce an expression, that, when evaluated, constructs
433/// the `TokenStream` `[Ident("a"), Punct('+', Alone), Ident("b")]`.
434///
435/// Unquoting is done with `$`, and works by taking the single next ident as the unquoted term.
436/// To quote `$` itself, use `$$`.
437#[unstable(feature = "proc_macro_quote", issue = "54722")]
438#[allow_internal_unstable(proc_macro_def_site, proc_macro_internals, proc_macro_totokens)]
439#[rustc_builtin_macro]
440pub macro quote($($t:tt)*) {
441 /* compiler built-in */
442}
443
444#[unstable(feature = "proc_macro_internals", issue = "27812")]
445#[doc(hidden)]
446mod quote;
447
448/// A region of source code, along with macro expansion information.
449#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
450#[derive(Copy, Clone)]
451pub struct Span(bridge::client::Span);
452
453#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
454impl !Send for Span {}
455#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
456impl !Sync for Span {}
457
458macro_rules! diagnostic_method {
459 ($name:ident, $level:expr) => {
460 /// Creates a new `Diagnostic` with the given `message` at the span
461 /// `self`.
462 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
463 pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic {
464 Diagnostic::spanned(self, $level, message)
465 }
466 };
467}
468
469impl Span {
470 /// A span that resolves at the macro definition site.
471 #[unstable(feature = "proc_macro_def_site", issue = "54724")]
472 pub fn def_site() -> Span {
473 Span(bridge::client::Span::def_site())
474 }
475
476 /// The span of the invocation of the current procedural macro.
477 /// Identifiers created with this span will be resolved as if they were written
478 /// directly at the macro call location (call-site hygiene) and other code
479 /// at the macro call site will be able to refer to them as well.
480 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
481 pub fn call_site() -> Span {
482 Span(bridge::client::Span::call_site())
483 }
484
485 /// A span that represents `macro_rules` hygiene, and sometimes resolves at the macro
486 /// definition site (local variables, labels, `$crate`) and sometimes at the macro
487 /// call site (everything else).
488 /// The span location is taken from the call-site.
489 #[stable(feature = "proc_macro_mixed_site", since = "1.45.0")]
490 pub fn mixed_site() -> Span {
491 Span(bridge::client::Span::mixed_site())
492 }
493
494 /// The `Span` for the tokens in the previous macro expansion from which
495 /// `self` was generated from, if any.
496 #[unstable(feature = "proc_macro_span", issue = "54725")]
497 pub fn parent(&self) -> Option<Span> {
498 self.0.parent().map(Span)
499 }
500
501 /// The span for the origin source code that `self` was generated from. If
502 /// this `Span` wasn't generated from other macro expansions then the return
503 /// value is the same as `*self`.
504 #[unstable(feature = "proc_macro_span", issue = "54725")]
505 pub fn source(&self) -> Span {
506 Span(self.0.source())
507 }
508
509 /// Returns the span's byte position range in the source file.
510 #[unstable(feature = "proc_macro_span", issue = "54725")]
511 pub fn byte_range(&self) -> Range<usize> {
512 self.0.byte_range()
513 }
514
515 /// Creates an empty span pointing to directly before this span.
516 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
517 pub fn start(&self) -> Span {
518 Span(self.0.start())
519 }
520
521 /// Creates an empty span pointing to directly after this span.
522 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
523 pub fn end(&self) -> Span {
524 Span(self.0.end())
525 }
526
527 /// The one-indexed line of the source file where the span starts.
528 ///
529 /// To obtain the line of the span's end, use `span.end().line()`.
530 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
531 pub fn line(&self) -> usize {
532 self.0.line()
533 }
534
535 /// The one-indexed column of the source file where the span starts.
536 ///
537 /// To obtain the column of the span's end, use `span.end().column()`.
538 #[stable(feature = "proc_macro_span_location", since = "1.88.0")]
539 pub fn column(&self) -> usize {
540 self.0.column()
541 }
542
543 /// The path to the source file in which this span occurs, for display purposes.
544 ///
545 /// This might not correspond to a valid file system path.
546 /// It might be remapped (e.g. `"/src/lib.rs"`) or an artificial path (e.g. `"<command line>"`).
547 #[stable(feature = "proc_macro_span_file", since = "1.88.0")]
548 pub fn file(&self) -> String {
549 self.0.file()
550 }
551
552 /// The path to the source file in which this span occurs on the local file system.
553 ///
554 /// This is the actual path on disk. It is unaffected by path remapping.
555 ///
556 /// This path should not be embedded in the output of the macro; prefer `file()` instead.
557 #[stable(feature = "proc_macro_span_file", since = "1.88.0")]
558 pub fn local_file(&self) -> Option<PathBuf> {
559 self.0.local_file().map(|s| PathBuf::from(s))
560 }
561
562 /// Creates a new span encompassing `self` and `other`.
563 ///
564 /// Returns `None` if `self` and `other` are from different files.
565 #[unstable(feature = "proc_macro_span", issue = "54725")]
566 pub fn join(&self, other: Span) -> Option<Span> {
567 self.0.join(other.0).map(Span)
568 }
569
570 /// Creates a new span with the same line/column information as `self` but
571 /// that resolves symbols as though it were at `other`.
572 #[stable(feature = "proc_macro_span_resolved_at", since = "1.45.0")]
573 pub fn resolved_at(&self, other: Span) -> Span {
574 Span(self.0.resolved_at(other.0))
575 }
576
577 /// Creates a new span with the same name resolution behavior as `self` but
578 /// with the line/column information of `other`.
579 #[stable(feature = "proc_macro_span_located_at", since = "1.45.0")]
580 pub fn located_at(&self, other: Span) -> Span {
581 other.resolved_at(*self)
582 }
583
584 /// Compares two spans to see if they're equal.
585 #[unstable(feature = "proc_macro_span", issue = "54725")]
586 pub fn eq(&self, other: &Span) -> bool {
587 self.0 == other.0
588 }
589
590 /// Returns the source text behind a span. This preserves the original source
591 /// code, including spaces and comments. It only returns a result if the span
592 /// corresponds to real source code.
593 ///
594 /// Note: The observable result of a macro should only rely on the tokens and
595 /// not on this source text. The result of this function is a best effort to
596 /// be used for diagnostics only.
597 #[stable(feature = "proc_macro_source_text", since = "1.66.0")]
598 pub fn source_text(&self) -> Option<String> {
599 self.0.source_text()
600 }
601
602 // Used by the implementation of `Span::quote`
603 #[doc(hidden)]
604 #[unstable(feature = "proc_macro_internals", issue = "27812")]
605 pub fn save_span(&self) -> usize {
606 self.0.save_span()
607 }
608
609 // Used by the implementation of `Span::quote`
610 #[doc(hidden)]
611 #[unstable(feature = "proc_macro_internals", issue = "27812")]
612 pub fn recover_proc_macro_span(id: usize) -> Span {
613 Span(bridge::client::Span::recover_proc_macro_span(id))
614 }
615
616 diagnostic_method!(error, Level::Error);
617 diagnostic_method!(warning, Level::Warning);
618 diagnostic_method!(note, Level::Note);
619 diagnostic_method!(help, Level::Help);
620}
621
622/// Prints a span in a form convenient for debugging.
623#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
624impl fmt::Debug for Span {
625 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
626 self.0.fmt(f)
627 }
628}
629
630/// A single token or a delimited sequence of token trees (e.g., `[1, (), ..]`).
631#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
632#[derive(Clone)]
633pub enum TokenTree {
634 /// A token stream surrounded by bracket delimiters.
635 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
636 Group(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Group),
637 /// An identifier.
638 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
639 Ident(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Ident),
640 /// A single punctuation character (`+`, `,`, `$`, etc.).
641 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
642 Punct(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Punct),
643 /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
644 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
645 Literal(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Literal),
646}
647
648#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
649impl !Send for TokenTree {}
650#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
651impl !Sync for TokenTree {}
652
653impl TokenTree {
654 /// Returns the span of this tree, delegating to the `span` method of
655 /// the contained token or a delimited stream.
656 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
657 pub fn span(&self) -> Span {
658 match *self {
659 TokenTree::Group(ref t) => t.span(),
660 TokenTree::Ident(ref t) => t.span(),
661 TokenTree::Punct(ref t) => t.span(),
662 TokenTree::Literal(ref t) => t.span(),
663 }
664 }
665
666 /// Configures the span for *only this token*.
667 ///
668 /// Note that if this token is a `Group` then this method will not configure
669 /// the span of each of the internal tokens, this will simply delegate to
670 /// the `set_span` method of each variant.
671 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
672 pub fn set_span(&mut self, span: Span) {
673 match *self {
674 TokenTree::Group(ref mut t) => t.set_span(span),
675 TokenTree::Ident(ref mut t) => t.set_span(span),
676 TokenTree::Punct(ref mut t) => t.set_span(span),
677 TokenTree::Literal(ref mut t) => t.set_span(span),
678 }
679 }
680}
681
682/// Prints token tree in a form convenient for debugging.
683#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
684impl fmt::Debug for TokenTree {
685 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
686 // Each of these has the name in the struct type in the derived debug,
687 // so don't bother with an extra layer of indirection
688 match *self {
689 TokenTree::Group(ref tt) => tt.fmt(f),
690 TokenTree::Ident(ref tt) => tt.fmt(f),
691 TokenTree::Punct(ref tt) => tt.fmt(f),
692 TokenTree::Literal(ref tt) => tt.fmt(f),
693 }
694 }
695}
696
697#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
698impl From<Group> for TokenTree {
699 fn from(g: Group) -> TokenTree {
700 TokenTree::Group(g)
701 }
702}
703
704#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
705impl From<Ident> for TokenTree {
706 fn from(g: Ident) -> TokenTree {
707 TokenTree::Ident(g)
708 }
709}
710
711#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
712impl From<Punct> for TokenTree {
713 fn from(g: Punct) -> TokenTree {
714 TokenTree::Punct(g)
715 }
716}
717
718#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
719impl From<Literal> for TokenTree {
720 fn from(g: Literal) -> TokenTree {
721 TokenTree::Literal(g)
722 }
723}
724
725/// Prints the token tree as a string that is supposed to be losslessly convertible back
726/// into the same token tree (modulo spans), except for possibly `TokenTree::Group`s
727/// with `Delimiter::None` delimiters and negative numeric literals.
728///
729/// Note: the exact form of the output is subject to change, e.g. there might
730/// be changes in the whitespace used between tokens. Therefore, you should
731/// *not* do any kind of simple substring matching on the output string (as
732/// produced by `to_string`) to implement a proc macro, because that matching
733/// might stop working if such changes happen. Instead, you should work at the
734/// `TokenTree` level, e.g. matching against `TokenTree::Ident`,
735/// `TokenTree::Punct`, or `TokenTree::Literal`.
736#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
737impl fmt::Display for TokenTree {
738 #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
739 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
740 match self {
741 TokenTree::Group(t) => write!(f, "{t}"),
742 TokenTree::Ident(t) => write!(f, "{t}"),
743 TokenTree::Punct(t) => write!(f, "{t}"),
744 TokenTree::Literal(t) => write!(f, "{t}"),
745 }
746 }
747}
748
749/// A delimited token stream.
750///
751/// A `Group` internally contains a `TokenStream` which is surrounded by `Delimiter`s.
752#[derive(Clone)]
753#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
754pub struct Group(bridge::Group<bridge::client::TokenStream, bridge::client::Span>);
755
756#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
757impl !Send for Group {}
758#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
759impl !Sync for Group {}
760
761/// Describes how a sequence of token trees is delimited.
762#[derive(Copy, Clone, Debug, PartialEq, Eq)]
763#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
764pub enum Delimiter {
765 /// `( ... )`
766 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
767 Parenthesis,
768 /// `{ ... }`
769 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
770 Brace,
771 /// `[ ... ]`
772 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
773 Bracket,
774 /// `∅ ... ∅`
775 /// An invisible delimiter, that may, for example, appear around tokens coming from a
776 /// "macro variable" `$var`. It is important to preserve operator priorities in cases like
777 /// `$var * 3` where `$var` is `1 + 2`.
778 /// Invisible delimiters might not survive roundtrip of a token stream through a string.
779 ///
780 /// <div class="warning">
781 ///
782 /// Note: rustc currently can ignore the grouping of tokens delimited by `None` in the output
783 /// of a proc_macro. Only `None`-delimited groups created by a macro_rules macro in the input
784 /// of a proc_macro macro are preserved, and only in very specific circumstances.
785 /// Any `None`-delimited groups (re)created by a proc_macro will therefore not preserve
786 /// operator priorities as indicated above. The other `Delimiter` variants should be used
787 /// instead in this context. This is a rustc bug. For details, see
788 /// [rust-lang/rust#67062](https://github.com/rust-lang/rust/issues/67062).
789 ///
790 /// </div>
791 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
792 None,
793}
794
795impl Group {
796 /// Creates a new `Group` with the given delimiter and token stream.
797 ///
798 /// This constructor will set the span for this group to
799 /// `Span::call_site()`. To change the span you can use the `set_span`
800 /// method below.
801 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
802 pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group {
803 Group(bridge::Group {
804 delimiter,
805 stream: stream.0,
806 span: bridge::DelimSpan::from_single(Span::call_site().0),
807 })
808 }
809
810 /// Returns the delimiter of this `Group`
811 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
812 pub fn delimiter(&self) -> Delimiter {
813 self.0.delimiter
814 }
815
816 /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
817 ///
818 /// Note that the returned token stream does not include the delimiter
819 /// returned above.
820 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
821 pub fn stream(&self) -> TokenStream {
822 TokenStream(self.0.stream.clone())
823 }
824
825 /// Returns the span for the delimiters of this token stream, spanning the
826 /// entire `Group`.
827 ///
828 /// ```text
829 /// pub fn span(&self) -> Span {
830 /// ^^^^^^^
831 /// ```
832 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
833 pub fn span(&self) -> Span {
834 Span(self.0.span.entire)
835 }
836
837 /// Returns the span pointing to the opening delimiter of this group.
838 ///
839 /// ```text
840 /// pub fn span_open(&self) -> Span {
841 /// ^
842 /// ```
843 #[stable(feature = "proc_macro_group_span", since = "1.55.0")]
844 pub fn span_open(&self) -> Span {
845 Span(self.0.span.open)
846 }
847
848 /// Returns the span pointing to the closing delimiter of this group.
849 ///
850 /// ```text
851 /// pub fn span_close(&self) -> Span {
852 /// ^
853 /// ```
854 #[stable(feature = "proc_macro_group_span", since = "1.55.0")]
855 pub fn span_close(&self) -> Span {
856 Span(self.0.span.close)
857 }
858
859 /// Configures the span for this `Group`'s delimiters, but not its internal
860 /// tokens.
861 ///
862 /// This method will **not** set the span of all the internal tokens spanned
863 /// by this group, but rather it will only set the span of the delimiter
864 /// tokens at the level of the `Group`.
865 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
866 pub fn set_span(&mut self, span: Span) {
867 self.0.span = bridge::DelimSpan::from_single(span.0);
868 }
869}
870
871/// Prints the group as a string that should be losslessly convertible back
872/// into the same group (modulo spans), except for possibly `TokenTree::Group`s
873/// with `Delimiter::None` delimiters.
874#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
875impl fmt::Display for Group {
876 #[allow(clippy::recursive_format_impl)] // clippy doesn't see the specialization
877 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
878 write!(f, "{}", TokenStream::from(TokenTree::from(self.clone())))
879 }
880}
881
882#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
883impl fmt::Debug for Group {
884 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
885 f.debug_struct("Group")
886 .field("delimiter", &self.delimiter())
887 .field("stream", &self.stream())
888 .field("span", &self.span())
889 .finish()
890 }
891}
892
893/// A `Punct` is a single punctuation character such as `+`, `-` or `#`.
894///
895/// Multi-character operators like `+=` are represented as two instances of `Punct` with different
896/// forms of `Spacing` returned.
897#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
898#[derive(Clone)]
899pub struct Punct(bridge::Punct<bridge::client::Span>);
900
901#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
902impl !Send for Punct {}
903#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
904impl !Sync for Punct {}
905
906/// Indicates whether a `Punct` token can join with the following token
907/// to form a multi-character operator.
908#[derive(Copy, Clone, Debug, PartialEq, Eq)]
909#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
910pub enum Spacing {
911 /// A `Punct` token can join with the following token to form a multi-character operator.
912 ///
913 /// In token streams constructed using proc macro interfaces, `Joint` punctuation tokens can be
914 /// followed by any other tokens. However, in token streams parsed from source code, the
915 /// compiler will only set spacing to `Joint` in the following cases.
916 /// - When a `Punct` is immediately followed by another `Punct` without a whitespace. E.g. `+`
917 /// is `Joint` in `+=` and `++`.
918 /// - When a single quote `'` is immediately followed by an identifier without a whitespace.
919 /// E.g. `'` is `Joint` in `'lifetime`.
920 ///
921 /// This list may be extended in the future to enable more token combinations.
922 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
923 Joint,
924 /// A `Punct` token cannot join with the following token to form a multi-character operator.
925 ///
926 /// `Alone` punctuation tokens can be followed by any other tokens. In token streams parsed
927 /// from source code, the compiler will set spacing to `Alone` in all cases not covered by the
928 /// conditions for `Joint` above. E.g. `+` is `Alone` in `+ =`, `+ident` and `+()`. In
929 /// particular, tokens not followed by anything will be marked as `Alone`.
930 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
931 Alone,
932}
933
934impl Punct {
935 /// Creates a new `Punct` from the given character and spacing.
936 /// The `ch` argument must be a valid punctuation character permitted by the language,
937 /// otherwise the function will panic.
938 ///
939 /// The returned `Punct` will have the default span of `Span::call_site()`
940 /// which can be further configured with the `set_span` method below.
941 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
942 pub fn new(ch: char, spacing: Spacing) -> Punct {
943 const LEGAL_CHARS: &[char] = &[
944 '=', '<', '>', '!', '~', '+', '-', '*', '/', '%', '^', '&', '|', '@', '.', ',', ';',
945 ':', '#', '$', '?', '\'',
946 ];
947 if !LEGAL_CHARS.contains(&ch) {
948 panic!("unsupported character `{:?}`", ch);
949 }
950 Punct(bridge::Punct {
951 ch: ch as u8,
952 joint: spacing == Spacing::Joint,
953 span: Span::call_site().0,
954 })
955 }
956
957 /// Returns the value of this punctuation character as `char`.
958 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
959 pub fn as_char(&self) -> char {
960 self.0.ch as char
961 }
962
963 /// Returns the spacing of this punctuation character, indicating whether it can be potentially
964 /// combined into a multi-character operator with the following token (`Joint`), or whether the
965 /// operator has definitely ended (`Alone`).
966 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
967 pub fn spacing(&self) -> Spacing {
968 if self.0.joint { Spacing::Joint } else { Spacing::Alone }
969 }
970
971 /// Returns the span for this punctuation character.
972 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
973 pub fn span(&self) -> Span {
974 Span(self.0.span)
975 }
976
977 /// Configure the span for this punctuation character.
978 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
979 pub fn set_span(&mut self, span: Span) {
980 self.0.span = span.0;
981 }
982}
983
984/// Prints the punctuation character as a string that should be losslessly convertible
985/// back into the same character.
986#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
987impl fmt::Display for Punct {
988 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
989 write!(f, "{}", self.as_char())
990 }
991}
992
993#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
994impl fmt::Debug for Punct {
995 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
996 f.debug_struct("Punct")
997 .field("ch", &self.as_char())
998 .field("spacing", &self.spacing())
999 .field("span", &self.span())
1000 .finish()
1001 }
1002}
1003
1004#[stable(feature = "proc_macro_punct_eq", since = "1.50.0")]
1005impl PartialEq<char> for Punct {
1006 fn eq(&self, rhs: &char) -> bool {
1007 self.as_char() == *rhs
1008 }
1009}
1010
1011#[stable(feature = "proc_macro_punct_eq_flipped", since = "1.52.0")]
1012impl PartialEq<Punct> for char {
1013 fn eq(&self, rhs: &Punct) -> bool {
1014 *self == rhs.as_char()
1015 }
1016}
1017
1018/// An identifier (`ident`).
1019#[derive(Clone)]
1020#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1021pub struct Ident(bridge::Ident<bridge::client::Span, bridge::client::Symbol>);
1022
1023impl Ident {
1024 /// Creates a new `Ident` with the given `string` as well as the specified
1025 /// `span`.
1026 /// The `string` argument must be a valid identifier permitted by the
1027 /// language (including keywords, e.g. `self` or `fn`). Otherwise, the function will panic.
1028 ///
1029 /// Note that `span`, currently in rustc, configures the hygiene information
1030 /// for this identifier.
1031 ///
1032 /// As of this time `Span::call_site()` explicitly opts-in to "call-site" hygiene
1033 /// meaning that identifiers created with this span will be resolved as if they were written
1034 /// directly at the location of the macro call, and other code at the macro call site will be
1035 /// able to refer to them as well.
1036 ///
1037 /// Later spans like `Span::def_site()` will allow to opt-in to "definition-site" hygiene
1038 /// meaning that identifiers created with this span will be resolved at the location of the
1039 /// macro definition and other code at the macro call site will not be able to refer to them.
1040 ///
1041 /// Due to the current importance of hygiene this constructor, unlike other
1042 /// tokens, requires a `Span` to be specified at construction.
1043 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1044 pub fn new(string: &str, span: Span) -> Ident {
1045 Ident(bridge::Ident {
1046 sym: bridge::client::Symbol::new_ident(string, false),
1047 is_raw: false,
1048 span: span.0,
1049 })
1050 }
1051
1052 /// Same as `Ident::new`, but creates a raw identifier (`r#ident`).
1053 /// The `string` argument be a valid identifier permitted by the language
1054 /// (including keywords, e.g. `fn`). Keywords which are usable in path segments
1055 /// (e.g. `self`, `super`) are not supported, and will cause a panic.
1056 #[stable(feature = "proc_macro_raw_ident", since = "1.47.0")]
1057 pub fn new_raw(string: &str, span: Span) -> Ident {
1058 Ident(bridge::Ident {
1059 sym: bridge::client::Symbol::new_ident(string, true),
1060 is_raw: true,
1061 span: span.0,
1062 })
1063 }
1064
1065 /// Returns the span of this `Ident`, encompassing the entire string returned
1066 /// by [`to_string`](ToString::to_string).
1067 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1068 pub fn span(&self) -> Span {
1069 Span(self.0.span)
1070 }
1071
1072 /// Configures the span of this `Ident`, possibly changing its hygiene context.
1073 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1074 pub fn set_span(&mut self, span: Span) {
1075 self.0.span = span.0;
1076 }
1077}
1078
1079/// Prints the identifier as a string that should be losslessly convertible back
1080/// into the same identifier.
1081#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1082impl fmt::Display for Ident {
1083 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1084 if self.0.is_raw {
1085 f.write_str("r#")?;
1086 }
1087 fmt::Display::fmt(&self.0.sym, f)
1088 }
1089}
1090
1091#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1092impl fmt::Debug for Ident {
1093 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1094 f.debug_struct("Ident")
1095 .field("ident", &self.to_string())
1096 .field("span", &self.span())
1097 .finish()
1098 }
1099}
1100
1101/// A literal string (`"hello"`), byte string (`b"hello"`), C string (`c"hello"`),
1102/// character (`'a'`), byte character (`b'a'`), an integer or floating point number
1103/// with or without a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
1104/// Boolean literals like `true` and `false` do not belong here, they are `Ident`s.
1105#[derive(Clone)]
1106#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1107pub struct Literal(bridge::Literal<bridge::client::Span, bridge::client::Symbol>);
1108
1109macro_rules! suffixed_int_literals {
1110 ($($name:ident => <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>k</mi><mi>i</mi><mi>n</mi><mi>d</mi><mo>:</mo><mi>i</mi><mi>d</mi><mi>e</mi><mi>n</mi><mi>t</mi><mo separator="true">,</mo><mo stretchy="false">)</mo><mo>∗</mo><mo stretchy="false">)</mo><mo>=</mo><mo>></mo><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">kind:ident,)*) => (</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">kin</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">i</span><span class="mord mathnormal">d</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mpunct">,</span><span class="mspace" style="margin-right:0.1667em;"></span><span class="mclose">)</span><span class="mord">∗</span><span class="mclose">)</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=></span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mopen">(</span></span></span></span>(
1111 /// Creates a new suffixed integer literal with the specified value.
1112 ///
1113 /// This function will create an integer like `1u32` where the integer
1114 /// value specified is the first part of the token and the integral is
1115 /// also suffixed at the end.
1116 /// Literals created from negative numbers might not survive round-trips through
1117 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1118 ///
1119 /// Literals created through this method have the `Span::call_site()`
1120 /// span by default, which can be configured with the `set_span` method
1121 /// below.
1122 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1123 pub fn <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>n</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo stretchy="false">(</mo><mi>n</mi><mo>:</mo></mrow><annotation encoding="application/x-tex">name(n: </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">nam</span><span class="mord mathnormal">e</span><span class="mopen">(</span><span class="mord mathnormal">n</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span></span></span></span>kind) -> Literal {
1124 Literal(bridge::Literal {
1125 kind: bridge::LitKind::Integer,
1126 symbol: bridge::client::Symbol::new(&n.to_string()),
1127 suffix: Some(bridge::client::Symbol::new(stringify!($kind))),
1128 span: Span::call_site().0,
1129 })
1130 }
1131 )*)
1132}
1133
1134macro_rules! unsuffixed_int_literals {
1135 ($($name:ident => <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>k</mi><mi>i</mi><mi>n</mi><mi>d</mi><mo>:</mo><mi>i</mi><mi>d</mi><mi>e</mi><mi>n</mi><mi>t</mi><mo separator="true">,</mo><mo stretchy="false">)</mo><mo>∗</mo><mo stretchy="false">)</mo><mo>=</mo><mo>></mo><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">kind:ident,)*) => (</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">kin</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">i</span><span class="mord mathnormal">d</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mord mathnormal">t</span><span class="mpunct">,</span><span class="mspace" style="margin-right:0.1667em;"></span><span class="mclose">)</span><span class="mord">∗</span><span class="mclose">)</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=></span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mopen">(</span></span></span></span>(
1136 /// Creates a new unsuffixed integer literal with the specified value.
1137 ///
1138 /// This function will create an integer like `1` where the integer
1139 /// value specified is the first part of the token. No suffix is
1140 /// specified on this token, meaning that invocations like
1141 /// `Literal::i8_unsuffixed(1)` are equivalent to
1142 /// `Literal::u32_unsuffixed(1)`.
1143 /// Literals created from negative numbers might not survive rountrips through
1144 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1145 ///
1146 /// Literals created through this method have the `Span::call_site()`
1147 /// span by default, which can be configured with the `set_span` method
1148 /// below.
1149 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1150 pub fn <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>n</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo stretchy="false">(</mo><mi>n</mi><mo>:</mo></mrow><annotation encoding="application/x-tex">name(n: </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">nam</span><span class="mord mathnormal">e</span><span class="mopen">(</span><span class="mord mathnormal">n</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span></span></span></span>kind) -> Literal {
1151 Literal(bridge::Literal {
1152 kind: bridge::LitKind::Integer,
1153 symbol: bridge::client::Symbol::new(&n.to_string()),
1154 suffix: None,
1155 span: Span::call_site().0,
1156 })
1157 }
1158 )*)
1159}
1160
1161impl Literal {
1162 fn new(kind: bridge::LitKind, value: &str, suffix: Option<&str>) -> Self {
1163 Literal(bridge::Literal {
1164 kind,
1165 symbol: bridge::client::Symbol::new(value),
1166 suffix: suffix.map(bridge::client::Symbol::new),
1167 span: Span::call_site().0,
1168 })
1169 }
1170
1171 suffixed_int_literals! {
1172 u8_suffixed => u8,
1173 u16_suffixed => u16,
1174 u32_suffixed => u32,
1175 u64_suffixed => u64,
1176 u128_suffixed => u128,
1177 usize_suffixed => usize,
1178 i8_suffixed => i8,
1179 i16_suffixed => i16,
1180 i32_suffixed => i32,
1181 i64_suffixed => i64,
1182 i128_suffixed => i128,
1183 isize_suffixed => isize,
1184 }
1185
1186 unsuffixed_int_literals! {
1187 u8_unsuffixed => u8,
1188 u16_unsuffixed => u16,
1189 u32_unsuffixed => u32,
1190 u64_unsuffixed => u64,
1191 u128_unsuffixed => u128,
1192 usize_unsuffixed => usize,
1193 i8_unsuffixed => i8,
1194 i16_unsuffixed => i16,
1195 i32_unsuffixed => i32,
1196 i64_unsuffixed => i64,
1197 i128_unsuffixed => i128,
1198 isize_unsuffixed => isize,
1199 }
1200
1201 /// Creates a new unsuffixed floating-point literal.
1202 ///
1203 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1204 /// the float's value is emitted directly into the token but no suffix is
1205 /// used, so it may be inferred to be a `f64` later in the compiler.
1206 /// Literals created from negative numbers might not survive rountrips through
1207 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1208 ///
1209 /// # Panics
1210 ///
1211 /// This function requires that the specified float is finite, for
1212 /// example if it is infinity or NaN this function will panic.
1213 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1214 pub fn f32_unsuffixed(n: f32) -> Literal {
1215 if !n.is_finite() {
1216 panic!("Invalid float literal {n}");
1217 }
1218 let mut repr = n.to_string();
1219 if !repr.contains('.') {
1220 repr.push_str(".0");
1221 }
1222 Literal::new(bridge::LitKind::Float, &repr, None)
1223 }
1224
1225 /// Creates a new suffixed floating-point literal.
1226 ///
1227 /// This constructor will create a literal like `1.0f32` where the value
1228 /// specified is the preceding part of the token and `f32` is the suffix of
1229 /// the token. This token will always be inferred to be an `f32` in the
1230 /// compiler.
1231 /// Literals created from negative numbers might not survive rountrips through
1232 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1233 ///
1234 /// # Panics
1235 ///
1236 /// This function requires that the specified float is finite, for
1237 /// example if it is infinity or NaN this function will panic.
1238 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1239 pub fn f32_suffixed(n: f32) -> Literal {
1240 if !n.is_finite() {
1241 panic!("Invalid float literal {n}");
1242 }
1243 Literal::new(bridge::LitKind::Float, &n.to_string(), Some("f32"))
1244 }
1245
1246 /// Creates a new unsuffixed floating-point literal.
1247 ///
1248 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1249 /// the float's value is emitted directly into the token but no suffix is
1250 /// used, so it may be inferred to be a `f64` later in the compiler.
1251 /// Literals created from negative numbers might not survive rountrips through
1252 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1253 ///
1254 /// # Panics
1255 ///
1256 /// This function requires that the specified float is finite, for
1257 /// example if it is infinity or NaN this function will panic.
1258 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1259 pub fn f64_unsuffixed(n: f64) -> Literal {
1260 if !n.is_finite() {
1261 panic!("Invalid float literal {n}");
1262 }
1263 let mut repr = n.to_string();
1264 if !repr.contains('.') {
1265 repr.push_str(".0");
1266 }
1267 Literal::new(bridge::LitKind::Float, &repr, None)
1268 }
1269
1270 /// Creates a new suffixed floating-point literal.
1271 ///
1272 /// This constructor will create a literal like `1.0f64` where the value
1273 /// specified is the preceding part of the token and `f64` is the suffix of
1274 /// the token. This token will always be inferred to be an `f64` in the
1275 /// compiler.
1276 /// Literals created from negative numbers might not survive rountrips through
1277 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1278 ///
1279 /// # Panics
1280 ///
1281 /// This function requires that the specified float is finite, for
1282 /// example if it is infinity or NaN this function will panic.
1283 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1284 pub fn f64_suffixed(n: f64) -> Literal {
1285 if !n.is_finite() {
1286 panic!("Invalid float literal {n}");
1287 }
1288 Literal::new(bridge::LitKind::Float, &n.to_string(), Some("f64"))
1289 }
1290
1291 /// String literal.
1292 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1293 pub fn string(string: &str) -> Literal {
1294 let escape = EscapeOptions {
1295 escape_single_quote: false,
1296 escape_double_quote: true,
1297 escape_nonascii: false,
1298 };
1299 let repr = escape_bytes(string.as_bytes(), escape);
1300 Literal::new(bridge::LitKind::Str, &repr, None)
1301 }
1302
1303 /// Character literal.
1304 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1305 pub fn character(ch: char) -> Literal {
1306 let escape = EscapeOptions {
1307 escape_single_quote: true,
1308 escape_double_quote: false,
1309 escape_nonascii: false,
1310 };
1311 let repr = escape_bytes(ch.encode_utf8(&mut [0u8; 4]).as_bytes(), escape);
1312 Literal::new(bridge::LitKind::Char, &repr, None)
1313 }
1314
1315 /// Byte character literal.
1316 #[stable(feature = "proc_macro_byte_character", since = "1.79.0")]
1317 pub fn byte_character(byte: u8) -> Literal {
1318 let escape = EscapeOptions {
1319 escape_single_quote: true,
1320 escape_double_quote: false,
1321 escape_nonascii: true,
1322 };
1323 let repr = escape_bytes(&[byte], escape);
1324 Literal::new(bridge::LitKind::Byte, &repr, None)
1325 }
1326
1327 /// Byte string literal.
1328 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1329 pub fn byte_string(bytes: &[u8]) -> Literal {
1330 let escape = EscapeOptions {
1331 escape_single_quote: false,
1332 escape_double_quote: true,
1333 escape_nonascii: true,
1334 };
1335 let repr = escape_bytes(bytes, escape);
1336 Literal::new(bridge::LitKind::ByteStr, &repr, None)
1337 }
1338
1339 /// C string literal.
1340 #[stable(feature = "proc_macro_c_str_literals", since = "1.79.0")]
1341 pub fn c_string(string: &CStr) -> Literal {
1342 let escape = EscapeOptions {
1343 escape_single_quote: false,
1344 escape_double_quote: true,
1345 escape_nonascii: false,
1346 };
1347 let repr = escape_bytes(string.to_bytes(), escape);
1348 Literal::new(bridge::LitKind::CStr, &repr, None)
1349 }
1350
1351 /// Returns the span encompassing this literal.
1352 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1353 pub fn span(&self) -> Span {
1354 Span(self.0.span)
1355 }
1356
1357 /// Configures the span associated for this literal.
1358 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1359 pub fn set_span(&mut self, span: Span) {
1360 self.0.span = span.0;
1361 }
1362
1363 /// Returns a `Span` that is a subset of `self.span()` containing only the
1364 /// source bytes in range `range`. Returns `None` if the would-be trimmed
1365 /// span is outside the bounds of `self`.
1366 // FIXME(SergioBenitez): check that the byte range starts and ends at a
1367 // UTF-8 boundary of the source. otherwise, it's likely that a panic will
1368 // occur elsewhere when the source text is printed.
1369 // FIXME(SergioBenitez): there is no way for the user to know what
1370 // `self.span()` actually maps to, so this method can currently only be
1371 // called blindly. For example, `to_string()` for the character 'c' returns
1372 // "'\u{63}'"; there is no way for the user to know whether the source text
1373 // was 'c' or whether it was '\u{63}'.
1374 #[unstable(feature = "proc_macro_span", issue = "54725")]
1375 pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
1376 self.0.span.subspan(range.start_bound().cloned(), range.end_bound().cloned()).map(Span)
1377 }
1378
1379 fn with_symbol_and_suffix<R>(&self, f: impl FnOnce(&str, &str) -> R) -> R {
1380 self.0.symbol.with(|symbol| match self.0.suffix {
1381 Some(suffix) => suffix.with(|suffix| f(symbol, suffix)),
1382 None => f(symbol, ""),
1383 })
1384 }
1385
1386 /// Invokes the callback with a `&[&str]` consisting of each part of the
1387 /// literal's representation. This is done to allow the `ToString` and
1388 /// `Display` implementations to borrow references to symbol values, and
1389 /// both be optimized to reduce overhead.
1390 fn with_stringify_parts<R>(&self, f: impl FnOnce(&[&str]) -> R) -> R {
1391 /// Returns a string containing exactly `num` '#' characters.
1392 /// Uses a 256-character source string literal which is always safe to
1393 /// index with a `u8` index.
1394 fn get_hashes_str(num: u8) -> &'static str {
1395 const HASHES: &str = "\
1396 ################################################################\
1397 ################################################################\
1398 ################################################################\
1399 ################################################################\
1400 ";
1401 const _: () = assert!(HASHES.len() == 256);
1402 &HASHES[..num as usize]
1403 }
1404
1405 self.with_symbol_and_suffix(|symbol, suffix| match self.0.kind {
1406 bridge::LitKind::Byte => f(&["b'", symbol, "'", suffix]),
1407 bridge::LitKind::Char => f(&["'", symbol, "'", suffix]),
1408 bridge::LitKind::Str => f(&["\"", symbol, "\"", suffix]),
1409 bridge::LitKind::StrRaw(n) => {
1410 let hashes = get_hashes_str(n);
1411 f(&["r", hashes, "\"", symbol, "\"", hashes, suffix])
1412 }
1413 bridge::LitKind::ByteStr => f(&["b\"", symbol, "\"", suffix]),
1414 bridge::LitKind::ByteStrRaw(n) => {
1415 let hashes = get_hashes_str(n);
1416 f(&["br", hashes, "\"", symbol, "\"", hashes, suffix])
1417 }
1418 bridge::LitKind::CStr => f(&["c\"", symbol, "\"", suffix]),
1419 bridge::LitKind::CStrRaw(n) => {
1420 let hashes = get_hashes_str(n);
1421 f(&["cr", hashes, "\"", symbol, "\"", hashes, suffix])
1422 }
1423
1424 bridge::LitKind::Integer | bridge::LitKind::Float | bridge::LitKind::ErrWithGuar => {
1425 f(&[symbol, suffix])
1426 }
1427 })
1428 }
1429
1430 /// Returns the unescaped string value if the current literal is a string or a string literal.
1431 #[unstable(feature = "proc_macro_value", issue = "136652")]
1432 pub fn str_value(&self) -> Result<String, ConversionErrorKind> {
1433 self.0.symbol.with(|symbol| match self.0.kind {
1434 bridge::LitKind::Str => {
1435 if symbol.contains('\\') {
1436 let mut buf = String::with_capacity(symbol.len());
1437 let mut error = None;
1438 // Force-inlining here is aggressive but the closure is
1439 // called on every char in the string, so it can be hot in
1440 // programs with many long strings containing escapes.
1441 unescape_unicode(
1442 symbol,
1443 Mode::Str,
1444 &mut #[inline(always)]
1445 |_, c| match c {
1446 Ok(c) => buf.push(c),
1447 Err(err) => {
1448 if err.is_fatal() {
1449 error = Some(ConversionErrorKind::FailedToUnescape(err));
1450 }
1451 }
1452 },
1453 );
1454 if let Some(error) = error { Err(error) } else { Ok(buf) }
1455 } else {
1456 Ok(symbol.to_string())
1457 }
1458 }
1459 bridge::LitKind::StrRaw(_) => Ok(symbol.to_string()),
1460 _ => Err(ConversionErrorKind::InvalidLiteralKind),
1461 })
1462 }
1463
1464 /// Returns the unescaped string value if the current literal is a c-string or a c-string
1465 /// literal.
1466 #[unstable(feature = "proc_macro_value", issue = "136652")]
1467 pub fn cstr_value(&self) -> Result<Vec<u8>, ConversionErrorKind> {
1468 self.0.symbol.with(|symbol| match self.0.kind {
1469 bridge::LitKind::CStr => {
1470 let mut error = None;
1471 let mut buf = Vec::with_capacity(symbol.len());
1472
1473 unescape_mixed(symbol, Mode::CStr, &mut |_span, c| match c {
1474 Ok(MixedUnit::Char(c)) => {
1475 buf.extend_from_slice(c.encode_utf8(&mut [0; 4]).as_bytes())
1476 }
1477 Ok(MixedUnit::HighByte(b)) => buf.push(b),
1478 Err(err) => {
1479 if err.is_fatal() {
1480 error = Some(ConversionErrorKind::FailedToUnescape(err));
1481 }
1482 }
1483 });
1484 if let Some(error) = error {
1485 Err(error)
1486 } else {
1487 buf.push(0);
1488 Ok(buf)
1489 }
1490 }
1491 bridge::LitKind::CStrRaw(_) => {
1492 // Raw strings have no escapes so we can convert the symbol
1493 // directly to a `Lrc<u8>` after appending the terminating NUL
1494 // char.
1495 let mut buf = symbol.to_owned().into_bytes();
1496 buf.push(0);
1497 Ok(buf)
1498 }
1499 _ => Err(ConversionErrorKind::InvalidLiteralKind),
1500 })
1501 }
1502
1503 /// Returns the unescaped string value if the current literal is a byte string or a byte string
1504 /// literal.
1505 #[unstable(feature = "proc_macro_value", issue = "136652")]
1506 pub fn byte_str_value(&self) -> Result<Vec<u8>, ConversionErrorKind> {
1507 self.0.symbol.with(|symbol| match self.0.kind {
1508 bridge::LitKind::ByteStr => {
1509 let mut buf = Vec::with_capacity(symbol.len());
1510 let mut error = None;
1511
1512 unescape_unicode(symbol, Mode::ByteStr, &mut |_, c| match c {
1513 Ok(c) => buf.push(byte_from_char(c)),
1514 Err(err) => {
1515 if err.is_fatal() {
1516 error = Some(ConversionErrorKind::FailedToUnescape(err));
1517 }
1518 }
1519 });
1520 if let Some(error) = error { Err(error) } else { Ok(buf) }
1521 }
1522 bridge::LitKind::ByteStrRaw(_) => {
1523 // Raw strings have no escapes so we can convert the symbol
1524 // directly to a `Lrc<u8>`.
1525 Ok(symbol.to_owned().into_bytes())
1526 }
1527 _ => Err(ConversionErrorKind::InvalidLiteralKind),
1528 })
1529 }
1530}
1531
1532/// Parse a single literal from its stringified representation.
1533///
1534/// In order to parse successfully, the input string must not contain anything
1535/// but the literal token. Specifically, it must not contain whitespace or
1536/// comments in addition to the literal.
1537///
1538/// The resulting literal token will have a `Span::call_site()` span.
1539///
1540/// NOTE: some errors may cause panics instead of returning `LexError`. We
1541/// reserve the right to change these errors into `LexError`s later.
1542#[stable(feature = "proc_macro_literal_parse", since = "1.54.0")]
1543impl FromStr for Literal {
1544 type Err = LexError;
1545
1546 fn from_str(src: &str) -> Result<Self, LexError> {
1547 match bridge::client::FreeFunctions::literal_from_str(src) {
1548 Ok(literal) => Ok(Literal(literal)),
1549 Err(()) => Err(LexError),
1550 }
1551 }
1552}
1553
1554/// Prints the literal as a string that should be losslessly convertible
1555/// back into the same literal (except for possible rounding for floating point literals).
1556#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1557impl fmt::Display for Literal {
1558 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1559 self.with_stringify_parts(|parts| {
1560 for part in parts {
1561 fmt::Display::fmt(part, f)?;
1562 }
1563 Ok(())
1564 })
1565 }
1566}
1567
1568#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1569impl fmt::Debug for Literal {
1570 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1571 f.debug_struct("Literal")
1572 // format the kind on one line even in {:#?} mode
1573 .field("kind", &format_args!("{:?}", self.0.kind))
1574 .field("symbol", &self.0.symbol)
1575 // format `Some("...")` on one line even in {:#?} mode
1576 .field("suffix", &format_args!("{:?}", self.0.suffix))
1577 .field("span", &self.0.span)
1578 .finish()
1579 }
1580}
1581
1582/// Tracked access to environment variables.
1583#[unstable(feature = "proc_macro_tracked_env", issue = "99515")]
1584pub mod tracked_env {
1585 use std::env::{self, VarError};
1586 use std::ffi::OsStr;
1587
1588 /// Retrieve an environment variable and add it to build dependency info.
1589 /// The build system executing the compiler will know that the variable was accessed during
1590 /// compilation, and will be able to rerun the build when the value of that variable changes.
1591 /// Besides the dependency tracking this function should be equivalent to `env::var` from the
1592 /// standard library, except that the argument must be UTF-8.
1593 #[unstable(feature = "proc_macro_tracked_env", issue = "99515")]
1594 pub fn var<K: AsRef<OsStr> + AsRef<str>>(key: K) -> Result<String, VarError> {
1595 let key: &str = key.as_ref();
1596 let value = crate:🌉:client::FreeFunctions::injected_env_var(key)
1597 .map_or_else(|| env::var(key), Ok);
1598 crate:🌉:client::FreeFunctions::track_env_var(key, value.as_deref().ok());
1599 value
1600 }
1601}
1602
1603/// Tracked access to additional files.
1604#[unstable(feature = "track_path", issue = "99515")]
1605pub mod tracked_path {
1606
1607 /// Track a file explicitly.
1608 ///
1609 /// Commonly used for tracking asset preprocessing.
1610 #[unstable(feature = "track_path", issue = "99515")]
1611 pub fn path<P: AsRef<str>>(path: P) {
1612 let path: &str = path.as_ref();
1613 crate:🌉:client::FreeFunctions::track_path(path);
1614 }
1615}