1 //! A support library for macro authors when defining new macros.
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]`.
8 //! See [the book] for more.
10 //! [the book]: ../book/ch19-06-macros.html#procedural-macros-for-generating-code-from-attributes
12 #![stable(feature = "proc_macro_lib", since = "1.15.0")]
13 #![deny(missing_docs)]
15 html_root_url = "https://doc.rust-lang.org/nightly/",
16 html_playground_url = "https://play.rust-lang.org/",
17 issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
18 test(no_crate_inject, attr(deny(warnings))),
19 test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
22 #![feature(staged_api)]
23 #![feature(allow_internal_unstable)]
25 #![feature(decl_macro)]
26 #![feature(extern_types)]
27 #![feature(in_band_lifetimes)]
28 #![feature(optin_builtin_traits)]
29 #![feature(rustc_attrs)]
30 #![feature(specialization)]
31 #![recursion_limit = "256"]
33 #[unstable(feature = "proc_macro_internals", issue = "27812")]
39 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
40 pub use diagnostic::{Diagnostic, Level, MultiSpan};
42 use std::ops::{Bound, RangeBounds};
43 use std::path::PathBuf;
44 use std::str::FromStr;
45 use std::{fmt, iter, mem};
47 /// The main type provided by this crate, representing an abstract stream of
48 /// tokens, or, more specifically, a sequence of token trees.
49 /// The type provide interfaces for iterating over those token trees and, conversely,
50 /// collecting a number of token trees into one stream.
52 /// This is both the input and output of `#[proc_macro]`, `#[proc_macro_attribute]`
53 /// and `#[proc_macro_derive]` definitions.
54 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
56 pub struct TokenStream(bridge::client::TokenStream);
58 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
59 impl !Send for TokenStream {}
60 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
61 impl !Sync for TokenStream {}
63 /// Error returned from `TokenStream::from_str`.
64 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
70 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
71 impl !Send for LexError {}
72 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
73 impl !Sync for LexError {}
76 /// Returns an empty `TokenStream` containing no token trees.
77 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
78 pub fn new() -> TokenStream {
79 TokenStream(bridge::client::TokenStream::new())
82 /// Checks if this `TokenStream` is empty.
83 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
84 pub fn is_empty(&self) -> bool {
89 /// Attempts to break the string into tokens and parse those tokens into a token stream.
90 /// May fail for a number of reasons, for example, if the string contains unbalanced delimiters
91 /// or characters not existing in the language.
92 /// All tokens in the parsed stream get `Span::call_site()` spans.
94 /// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to
95 /// change these errors into `LexError`s later.
96 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
97 impl FromStr for TokenStream {
100 fn from_str(src: &str) -> Result<TokenStream, LexError> {
101 Ok(TokenStream(bridge::client::TokenStream::from_str(src)))
105 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
106 // based on it (the reverse of the usual relationship between the two).
107 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
108 impl ToString for TokenStream {
109 fn to_string(&self) -> String {
114 /// Prints the token stream as a string that is supposed to be losslessly convertible back
115 /// into the same token stream (modulo spans), except for possibly `TokenTree::Group`s
116 /// with `Delimiter::None` delimiters and negative numeric literals.
117 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
118 impl fmt::Display for TokenStream {
119 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
120 f.write_str(&self.to_string())
124 /// Prints token in a form convenient for debugging.
125 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
126 impl fmt::Debug for TokenStream {
127 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
128 f.write_str("TokenStream ")?;
129 f.debug_list().entries(self.clone()).finish()
133 #[unstable(feature = "proc_macro_quote", issue = "54722")]
134 pub use quote::{quote, quote_span};
136 /// Creates a token stream containing a single token tree.
137 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
138 impl From<TokenTree> for TokenStream {
139 fn from(tree: TokenTree) -> TokenStream {
140 TokenStream(bridge::client::TokenStream::from_token_tree(match tree {
141 TokenTree::Group(tt) => bridge::TokenTree::Group(tt.0),
142 TokenTree::Punct(tt) => bridge::TokenTree::Punct(tt.0),
143 TokenTree::Ident(tt) => bridge::TokenTree::Ident(tt.0),
144 TokenTree::Literal(tt) => bridge::TokenTree::Literal(tt.0),
149 /// Collects a number of token trees into a single stream.
150 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
151 impl iter::FromIterator<TokenTree> for TokenStream {
152 fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self {
153 trees.into_iter().map(TokenStream::from).collect()
157 /// A "flattening" operation on token streams, collects token trees
158 /// from multiple token streams into a single stream.
159 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
160 impl iter::FromIterator<TokenStream> for TokenStream {
161 fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
162 let mut builder = bridge::client::TokenStreamBuilder::new();
163 streams.into_iter().for_each(|stream| builder.push(stream.0));
164 TokenStream(builder.build())
168 #[stable(feature = "token_stream_extend", since = "1.30.0")]
169 impl Extend<TokenTree> for TokenStream {
170 fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) {
171 self.extend(trees.into_iter().map(TokenStream::from));
175 #[stable(feature = "token_stream_extend", since = "1.30.0")]
176 impl Extend<TokenStream> for TokenStream {
177 fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
178 // FIXME(eddyb) Use an optimized implementation if/when possible.
179 *self = iter::once(mem::replace(self, Self::new())).chain(streams).collect();
183 /// Public implementation details for the `TokenStream` type, such as iterators.
184 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
185 pub mod token_stream {
186 use crate::{bridge, Group, Ident, Literal, Punct, TokenStream, TokenTree};
188 /// An iterator over `TokenStream`'s `TokenTree`s.
189 /// The iteration is "shallow", e.g., the iterator doesn't recurse into delimited groups,
190 /// and returns whole groups as token trees.
192 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
193 pub struct IntoIter(bridge::client::TokenStreamIter);
195 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
196 impl Iterator for IntoIter {
197 type Item = TokenTree;
199 fn next(&mut self) -> Option<TokenTree> {
200 self.0.next().map(|tree| match tree {
201 bridge::TokenTree::Group(tt) => TokenTree::Group(Group(tt)),
202 bridge::TokenTree::Punct(tt) => TokenTree::Punct(Punct(tt)),
203 bridge::TokenTree::Ident(tt) => TokenTree::Ident(Ident(tt)),
204 bridge::TokenTree::Literal(tt) => TokenTree::Literal(Literal(tt)),
209 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
210 impl IntoIterator for TokenStream {
211 type Item = TokenTree;
212 type IntoIter = IntoIter;
214 fn into_iter(self) -> IntoIter {
215 IntoIter(self.0.into_iter())
220 /// `quote!(..)` accepts arbitrary tokens and expands into a `TokenStream` describing the input.
221 /// For example, `quote!(a + b)` will produce a expression, that, when evaluated, constructs
222 /// the `TokenStream` `[Ident("a"), Punct('+', Alone), Ident("b")]`.
224 /// Unquoting is done with `$`, and works by taking the single next ident as the unquoted term.
225 /// To quote `$` itself, use `$$`.
226 #[unstable(feature = "proc_macro_quote", issue = "54722")]
227 #[allow_internal_unstable(proc_macro_def_site)]
228 #[rustc_builtin_macro]
229 pub macro quote($($t:tt)*) {
230 /* compiler built-in */
233 #[unstable(feature = "proc_macro_internals", issue = "27812")]
237 /// A region of source code, along with macro expansion information.
238 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
239 #[derive(Copy, Clone)]
240 pub struct Span(bridge::client::Span);
242 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
243 impl !Send for Span {}
244 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
245 impl !Sync for Span {}
247 macro_rules! diagnostic_method {
248 ($name:ident, $level:expr) => (
249 /// Creates a new `Diagnostic` with the given `message` at the span
251 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
252 pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic {
253 Diagnostic::spanned(self, $level, message)
259 /// A span that resolves at the macro definition site.
260 #[unstable(feature = "proc_macro_def_site", issue = "54724")]
261 pub fn def_site() -> Span {
262 Span(bridge::client::Span::def_site())
265 /// The span of the invocation of the current procedural macro.
266 /// Identifiers created with this span will be resolved as if they were written
267 /// directly at the macro call location (call-site hygiene) and other code
268 /// at the macro call site will be able to refer to them as well.
269 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
270 pub fn call_site() -> Span {
271 Span(bridge::client::Span::call_site())
274 /// A span that represents `macro_rules` hygiene, and sometimes resolves at the macro
275 /// definition site (local variables, labels, `$crate`) and sometimes at the macro
276 /// call site (everything else).
277 /// The span location is taken from the call-site.
278 #[unstable(feature = "proc_macro_mixed_site", issue = "65049")]
279 pub fn mixed_site() -> Span {
280 Span(bridge::client::Span::mixed_site())
283 /// The original source file into which this span points.
284 #[unstable(feature = "proc_macro_span", issue = "54725")]
285 pub fn source_file(&self) -> SourceFile {
286 SourceFile(self.0.source_file())
289 /// The `Span` for the tokens in the previous macro expansion from which
290 /// `self` was generated from, if any.
291 #[unstable(feature = "proc_macro_span", issue = "54725")]
292 pub fn parent(&self) -> Option<Span> {
293 self.0.parent().map(Span)
296 /// The span for the origin source code that `self` was generated from. If
297 /// this `Span` wasn't generated from other macro expansions then the return
298 /// value is the same as `*self`.
299 #[unstable(feature = "proc_macro_span", issue = "54725")]
300 pub fn source(&self) -> Span {
301 Span(self.0.source())
304 /// Gets the starting line/column in the source file for this span.
305 #[unstable(feature = "proc_macro_span", issue = "54725")]
306 pub fn start(&self) -> LineColumn {
310 /// Gets the ending line/column in the source file for this span.
311 #[unstable(feature = "proc_macro_span", issue = "54725")]
312 pub fn end(&self) -> LineColumn {
316 /// Creates a new span encompassing `self` and `other`.
318 /// Returns `None` if `self` and `other` are from different files.
319 #[unstable(feature = "proc_macro_span", issue = "54725")]
320 pub fn join(&self, other: Span) -> Option<Span> {
321 self.0.join(other.0).map(Span)
324 /// Creates a new span with the same line/column information as `self` but
325 /// that resolves symbols as though it were at `other`.
326 #[unstable(feature = "proc_macro_span", issue = "54725")]
327 pub fn resolved_at(&self, other: Span) -> Span {
328 Span(self.0.resolved_at(other.0))
331 /// Creates a new span with the same name resolution behavior as `self` but
332 /// with the line/column information of `other`.
333 #[unstable(feature = "proc_macro_span", issue = "54725")]
334 pub fn located_at(&self, other: Span) -> Span {
335 other.resolved_at(*self)
338 /// Compares to spans to see if they're equal.
339 #[unstable(feature = "proc_macro_span", issue = "54725")]
340 pub fn eq(&self, other: &Span) -> bool {
344 /// Returns the source text behind a span. This preserves the original source
345 /// code, including spaces and comments. It only returns a result if the span
346 /// corresponds to real source code.
348 /// Note: The observable result of a macro should only rely on the tokens and
349 /// not on this source text. The result of this function is a best effort to
350 /// be used for diagnostics only.
351 #[unstable(feature = "proc_macro_span", issue = "54725")]
352 pub fn source_text(&self) -> Option<String> {
356 diagnostic_method!(error, Level::Error);
357 diagnostic_method!(warning, Level::Warning);
358 diagnostic_method!(note, Level::Note);
359 diagnostic_method!(help, Level::Help);
362 /// Prints a span in a form convenient for debugging.
363 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
364 impl fmt::Debug for Span {
365 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
370 /// A line-column pair representing the start or end of a `Span`.
371 #[unstable(feature = "proc_macro_span", issue = "54725")]
372 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
373 pub struct LineColumn {
374 /// The 1-indexed line in the source file on which the span starts or ends (inclusive).
375 #[unstable(feature = "proc_macro_span", issue = "54725")]
377 /// The 0-indexed column (in UTF-8 characters) in the source file on which
378 /// the span starts or ends (inclusive).
379 #[unstable(feature = "proc_macro_span", issue = "54725")]
383 #[unstable(feature = "proc_macro_span", issue = "54725")]
384 impl !Send for LineColumn {}
385 #[unstable(feature = "proc_macro_span", issue = "54725")]
386 impl !Sync for LineColumn {}
388 /// The source file of a given `Span`.
389 #[unstable(feature = "proc_macro_span", issue = "54725")]
391 pub struct SourceFile(bridge::client::SourceFile);
394 /// Gets the path to this source file.
397 /// If the code span associated with this `SourceFile` was generated by an external macro, this
398 /// macro, this may not be an actual path on the filesystem. Use [`is_real`] to check.
400 /// Also note that even if `is_real` returns `true`, if `--remap-path-prefix` was passed on
401 /// the command line, the path as given may not actually be valid.
403 /// [`is_real`]: #method.is_real
404 #[unstable(feature = "proc_macro_span", issue = "54725")]
405 pub fn path(&self) -> PathBuf {
406 PathBuf::from(self.0.path())
409 /// Returns `true` if this source file is a real source file, and not generated by an external
410 /// macro's expansion.
411 #[unstable(feature = "proc_macro_span", issue = "54725")]
412 pub fn is_real(&self) -> bool {
413 // This is a hack until intercrate spans are implemented and we can have real source files
414 // for spans generated in external macros.
415 // https://github.com/rust-lang/rust/pull/43604#issuecomment-333334368
420 #[unstable(feature = "proc_macro_span", issue = "54725")]
421 impl fmt::Debug for SourceFile {
422 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
423 f.debug_struct("SourceFile")
424 .field("path", &self.path())
425 .field("is_real", &self.is_real())
430 #[unstable(feature = "proc_macro_span", issue = "54725")]
431 impl PartialEq for SourceFile {
432 fn eq(&self, other: &Self) -> bool {
437 #[unstable(feature = "proc_macro_span", issue = "54725")]
438 impl Eq for SourceFile {}
440 /// A single token or a delimited sequence of token trees (e.g., `[1, (), ..]`).
441 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
444 /// A token stream surrounded by bracket delimiters.
445 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
446 Group(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Group),
448 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
449 Ident(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Ident),
450 /// A single punctuation character (`+`, `,`, `$`, etc.).
451 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
452 Punct(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Punct),
453 /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
454 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
455 Literal(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Literal),
458 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
459 impl !Send for TokenTree {}
460 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
461 impl !Sync for TokenTree {}
464 /// Returns the span of this tree, delegating to the `span` method of
465 /// the contained token or a delimited stream.
466 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
467 pub fn span(&self) -> Span {
469 TokenTree::Group(ref t) => t.span(),
470 TokenTree::Ident(ref t) => t.span(),
471 TokenTree::Punct(ref t) => t.span(),
472 TokenTree::Literal(ref t) => t.span(),
476 /// Configures the span for *only this token*.
478 /// Note that if this token is a `Group` then this method will not configure
479 /// the span of each of the internal tokens, this will simply delegate to
480 /// the `set_span` method of each variant.
481 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
482 pub fn set_span(&mut self, span: Span) {
484 TokenTree::Group(ref mut t) => t.set_span(span),
485 TokenTree::Ident(ref mut t) => t.set_span(span),
486 TokenTree::Punct(ref mut t) => t.set_span(span),
487 TokenTree::Literal(ref mut t) => t.set_span(span),
492 /// Prints token tree in a form convenient for debugging.
493 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
494 impl fmt::Debug for TokenTree {
495 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
496 // Each of these has the name in the struct type in the derived debug,
497 // so don't bother with an extra layer of indirection
499 TokenTree::Group(ref tt) => tt.fmt(f),
500 TokenTree::Ident(ref tt) => tt.fmt(f),
501 TokenTree::Punct(ref tt) => tt.fmt(f),
502 TokenTree::Literal(ref tt) => tt.fmt(f),
507 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
508 impl From<Group> for TokenTree {
509 fn from(g: Group) -> TokenTree {
514 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
515 impl From<Ident> for TokenTree {
516 fn from(g: Ident) -> TokenTree {
521 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
522 impl From<Punct> for TokenTree {
523 fn from(g: Punct) -> TokenTree {
528 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
529 impl From<Literal> for TokenTree {
530 fn from(g: Literal) -> TokenTree {
531 TokenTree::Literal(g)
535 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
536 // based on it (the reverse of the usual relationship between the two).
537 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
538 impl ToString for TokenTree {
539 fn to_string(&self) -> String {
541 TokenTree::Group(ref t) => t.to_string(),
542 TokenTree::Ident(ref t) => t.to_string(),
543 TokenTree::Punct(ref t) => t.to_string(),
544 TokenTree::Literal(ref t) => t.to_string(),
549 /// Prints the token tree as a string that is supposed to be losslessly convertible back
550 /// into the same token tree (modulo spans), except for possibly `TokenTree::Group`s
551 /// with `Delimiter::None` delimiters and negative numeric literals.
552 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
553 impl fmt::Display for TokenTree {
554 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
555 f.write_str(&self.to_string())
559 /// A delimited token stream.
561 /// A `Group` internally contains a `TokenStream` which is surrounded by `Delimiter`s.
563 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
564 pub struct Group(bridge::client::Group);
566 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
567 impl !Send for Group {}
568 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
569 impl !Sync for Group {}
571 /// Describes how a sequence of token trees is delimited.
572 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
573 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
576 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
579 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
582 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
585 /// An implicit delimiter, that may, for example, appear around tokens coming from a
586 /// "macro variable" `$var`. It is important to preserve operator priorities in cases like
587 /// `$var * 3` where `$var` is `1 + 2`.
588 /// Implicit delimiters may not survive roundtrip of a token stream through a string.
589 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
594 /// Creates a new `Group` with the given delimiter and token stream.
596 /// This constructor will set the span for this group to
597 /// `Span::call_site()`. To change the span you can use the `set_span`
599 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
600 pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group {
601 Group(bridge::client::Group::new(delimiter, stream.0))
604 /// Returns the delimiter of this `Group`
605 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
606 pub fn delimiter(&self) -> Delimiter {
610 /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
612 /// Note that the returned token stream does not include the delimiter
614 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
615 pub fn stream(&self) -> TokenStream {
616 TokenStream(self.0.stream())
619 /// Returns the span for the delimiters of this token stream, spanning the
623 /// pub fn span(&self) -> Span {
626 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
627 pub fn span(&self) -> Span {
631 /// Returns the span pointing to the opening delimiter of this group.
634 /// pub fn span_open(&self) -> Span {
637 #[unstable(feature = "proc_macro_span", issue = "54725")]
638 pub fn span_open(&self) -> Span {
639 Span(self.0.span_open())
642 /// Returns the span pointing to the closing delimiter of this group.
645 /// pub fn span_close(&self) -> Span {
648 #[unstable(feature = "proc_macro_span", issue = "54725")]
649 pub fn span_close(&self) -> Span {
650 Span(self.0.span_close())
653 /// Configures the span for this `Group`'s delimiters, but not its internal
656 /// This method will **not** set the span of all the internal tokens spanned
657 /// by this group, but rather it will only set the span of the delimiter
658 /// tokens at the level of the `Group`.
659 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
660 pub fn set_span(&mut self, span: Span) {
661 self.0.set_span(span.0);
665 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
666 // based on it (the reverse of the usual relationship between the two).
667 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
668 impl ToString for Group {
669 fn to_string(&self) -> String {
670 TokenStream::from(TokenTree::from(self.clone())).to_string()
674 /// Prints the group as a string that should be losslessly convertible back
675 /// into the same group (modulo spans), except for possibly `TokenTree::Group`s
676 /// with `Delimiter::None` delimiters.
677 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
678 impl fmt::Display for Group {
679 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
680 f.write_str(&self.to_string())
684 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
685 impl fmt::Debug for Group {
686 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
687 f.debug_struct("Group")
688 .field("delimiter", &self.delimiter())
689 .field("stream", &self.stream())
690 .field("span", &self.span())
695 /// An `Punct` is an single punctuation character like `+`, `-` or `#`.
697 /// Multi-character operators like `+=` are represented as two instances of `Punct` with different
698 /// forms of `Spacing` returned.
699 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
701 pub struct Punct(bridge::client::Punct);
703 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
704 impl !Send for Punct {}
705 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
706 impl !Sync for Punct {}
708 /// Whether an `Punct` is followed immediately by another `Punct` or
709 /// followed by another token or whitespace.
710 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
711 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
713 /// e.g., `+` is `Alone` in `+ =`, `+ident` or `+()`.
714 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
716 /// e.g., `+` is `Joint` in `+=` or `'#`.
717 /// Additionally, single quote `'` can join with identifiers to form lifetimes `'ident`.
718 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
723 /// Creates a new `Punct` from the given character and spacing.
724 /// The `ch` argument must be a valid punctuation character permitted by the language,
725 /// otherwise the function will panic.
727 /// The returned `Punct` will have the default span of `Span::call_site()`
728 /// which can be further configured with the `set_span` method below.
729 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
730 pub fn new(ch: char, spacing: Spacing) -> Punct {
731 Punct(bridge::client::Punct::new(ch, spacing))
734 /// Returns the value of this punctuation character as `char`.
735 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
736 pub fn as_char(&self) -> char {
740 /// Returns the spacing of this punctuation character, indicating whether it's immediately
741 /// followed by another `Punct` in the token stream, so they can potentially be combined into
742 /// a multi-character operator (`Joint`), or it's followed by some other token or whitespace
743 /// (`Alone`) so the operator has certainly ended.
744 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
745 pub fn spacing(&self) -> Spacing {
749 /// Returns the span for this punctuation character.
750 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
751 pub fn span(&self) -> Span {
755 /// Configure the span for this punctuation character.
756 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
757 pub fn set_span(&mut self, span: Span) {
758 self.0 = self.0.with_span(span.0);
762 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
763 // based on it (the reverse of the usual relationship between the two).
764 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
765 impl ToString for Punct {
766 fn to_string(&self) -> String {
767 TokenStream::from(TokenTree::from(self.clone())).to_string()
771 /// Prints the punctuation character as a string that should be losslessly convertible
772 /// back into the same character.
773 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
774 impl fmt::Display for Punct {
775 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
776 f.write_str(&self.to_string())
780 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
781 impl fmt::Debug for Punct {
782 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
783 f.debug_struct("Punct")
784 .field("ch", &self.as_char())
785 .field("spacing", &self.spacing())
786 .field("span", &self.span())
791 /// An identifier (`ident`).
793 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
794 pub struct Ident(bridge::client::Ident);
797 /// Creates a new `Ident` with the given `string` as well as the specified
799 /// The `string` argument must be a valid identifier permitted by the
800 /// language, otherwise the function will panic.
802 /// Note that `span`, currently in rustc, configures the hygiene information
803 /// for this identifier.
805 /// As of this time `Span::call_site()` explicitly opts-in to "call-site" hygiene
806 /// meaning that identifiers created with this span will be resolved as if they were written
807 /// directly at the location of the macro call, and other code at the macro call site will be
808 /// able to refer to them as well.
810 /// Later spans like `Span::def_site()` will allow to opt-in to "definition-site" hygiene
811 /// meaning that identifiers created with this span will be resolved at the location of the
812 /// macro definition and other code at the macro call site will not be able to refer to them.
814 /// Due to the current importance of hygiene this constructor, unlike other
815 /// tokens, requires a `Span` to be specified at construction.
816 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
817 pub fn new(string: &str, span: Span) -> Ident {
818 Ident(bridge::client::Ident::new(string, span.0, false))
821 /// Same as `Ident::new`, but creates a raw identifier (`r#ident`).
822 #[unstable(feature = "proc_macro_raw_ident", issue = "54723")]
823 pub fn new_raw(string: &str, span: Span) -> Ident {
824 Ident(bridge::client::Ident::new(string, span.0, true))
827 /// Returns the span of this `Ident`, encompassing the entire string returned
829 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
830 pub fn span(&self) -> Span {
834 /// Configures the span of this `Ident`, possibly changing its hygiene context.
835 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
836 pub fn set_span(&mut self, span: Span) {
837 self.0 = self.0.with_span(span.0);
841 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
842 // based on it (the reverse of the usual relationship between the two).
843 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
844 impl ToString for Ident {
845 fn to_string(&self) -> String {
846 TokenStream::from(TokenTree::from(self.clone())).to_string()
850 /// Prints the identifier as a string that should be losslessly convertible
851 /// back into the same identifier.
852 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
853 impl fmt::Display for Ident {
854 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
855 f.write_str(&self.to_string())
859 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
860 impl fmt::Debug for Ident {
861 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
862 f.debug_struct("Ident")
863 .field("ident", &self.to_string())
864 .field("span", &self.span())
869 /// A literal string (`"hello"`), byte string (`b"hello"`),
870 /// character (`'a'`), byte character (`b'a'`), an integer or floating point number
871 /// with or without a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
872 /// Boolean literals like `true` and `false` do not belong here, they are `Ident`s.
874 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
875 pub struct Literal(bridge::client::Literal);
877 macro_rules! suffixed_int_literals {
878 ($($name:ident => $kind:ident,)*) => ($(
879 /// Creates a new suffixed integer literal with the specified value.
881 /// This function will create an integer like `1u32` where the integer
882 /// value specified is the first part of the token and the integral is
883 /// also suffixed at the end.
884 /// Literals created from negative numbers may not survive round-trips through
885 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
887 /// Literals created through this method have the `Span::call_site()`
888 /// span by default, which can be configured with the `set_span` method
890 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
891 pub fn $name(n: $kind) -> Literal {
892 Literal(bridge::client::Literal::typed_integer(&n.to_string(), stringify!($kind)))
897 macro_rules! unsuffixed_int_literals {
898 ($($name:ident => $kind:ident,)*) => ($(
899 /// Creates a new unsuffixed integer literal with the specified value.
901 /// This function will create an integer like `1` where the integer
902 /// value specified is the first part of the token. No suffix is
903 /// specified on this token, meaning that invocations like
904 /// `Literal::i8_unsuffixed(1)` are equivalent to
905 /// `Literal::u32_unsuffixed(1)`.
906 /// Literals created from negative numbers may not survive rountrips through
907 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
909 /// Literals created through this method have the `Span::call_site()`
910 /// span by default, which can be configured with the `set_span` method
912 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
913 pub fn $name(n: $kind) -> Literal {
914 Literal(bridge::client::Literal::integer(&n.to_string()))
920 suffixed_int_literals! {
925 u128_suffixed => u128,
926 usize_suffixed => usize,
931 i128_suffixed => i128,
932 isize_suffixed => isize,
935 unsuffixed_int_literals! {
937 u16_unsuffixed => u16,
938 u32_unsuffixed => u32,
939 u64_unsuffixed => u64,
940 u128_unsuffixed => u128,
941 usize_unsuffixed => usize,
943 i16_unsuffixed => i16,
944 i32_unsuffixed => i32,
945 i64_unsuffixed => i64,
946 i128_unsuffixed => i128,
947 isize_unsuffixed => isize,
950 /// Creates a new unsuffixed floating-point literal.
952 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
953 /// the float's value is emitted directly into the token but no suffix is
954 /// used, so it may be inferred to be a `f64` later in the compiler.
955 /// Literals created from negative numbers may not survive rountrips through
956 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
960 /// This function requires that the specified float is finite, for
961 /// example if it is infinity or NaN this function will panic.
962 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
963 pub fn f32_unsuffixed(n: f32) -> Literal {
965 panic!("Invalid float literal {}", n);
967 Literal(bridge::client::Literal::float(&n.to_string()))
970 /// Creates a new suffixed floating-point literal.
972 /// This constructor will create a literal like `1.0f32` where the value
973 /// specified is the preceding part of the token and `f32` is the suffix of
974 /// the token. This token will always be inferred to be an `f32` in the
976 /// Literals created from negative numbers may not survive rountrips through
977 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
981 /// This function requires that the specified float is finite, for
982 /// example if it is infinity or NaN this function will panic.
983 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
984 pub fn f32_suffixed(n: f32) -> Literal {
986 panic!("Invalid float literal {}", n);
988 Literal(bridge::client::Literal::f32(&n.to_string()))
991 /// Creates a new unsuffixed floating-point literal.
993 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
994 /// the float's value is emitted directly into the token but no suffix is
995 /// used, so it may be inferred to be a `f64` later in the compiler.
996 /// Literals created from negative numbers may not survive rountrips through
997 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1001 /// This function requires that the specified float is finite, for
1002 /// example if it is infinity or NaN this function will panic.
1003 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1004 pub fn f64_unsuffixed(n: f64) -> Literal {
1006 panic!("Invalid float literal {}", n);
1008 Literal(bridge::client::Literal::float(&n.to_string()))
1011 /// Creates a new suffixed floating-point literal.
1013 /// This constructor will create a literal like `1.0f64` where the value
1014 /// specified is the preceding part of the token and `f64` is the suffix of
1015 /// the token. This token will always be inferred to be an `f64` in the
1017 /// Literals created from negative numbers may not survive rountrips through
1018 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1022 /// This function requires that the specified float is finite, for
1023 /// example if it is infinity or NaN this function will panic.
1024 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1025 pub fn f64_suffixed(n: f64) -> Literal {
1027 panic!("Invalid float literal {}", n);
1029 Literal(bridge::client::Literal::f64(&n.to_string()))
1033 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1034 pub fn string(string: &str) -> Literal {
1035 Literal(bridge::client::Literal::string(string))
1038 /// Character literal.
1039 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1040 pub fn character(ch: char) -> Literal {
1041 Literal(bridge::client::Literal::character(ch))
1044 /// Byte string literal.
1045 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1046 pub fn byte_string(bytes: &[u8]) -> Literal {
1047 Literal(bridge::client::Literal::byte_string(bytes))
1050 /// Returns the span encompassing this literal.
1051 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1052 pub fn span(&self) -> Span {
1056 /// Configures the span associated for this literal.
1057 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1058 pub fn set_span(&mut self, span: Span) {
1059 self.0.set_span(span.0);
1062 /// Returns a `Span` that is a subset of `self.span()` containing only the
1063 /// source bytes in range `range`. Returns `None` if the would-be trimmed
1064 /// span is outside the bounds of `self`.
1065 // FIXME(SergioBenitez): check that the byte range starts and ends at a
1066 // UTF-8 boundary of the source. otherwise, it's likely that a panic will
1067 // occur elsewhere when the source text is printed.
1068 // FIXME(SergioBenitez): there is no way for the user to know what
1069 // `self.span()` actually maps to, so this method can currently only be
1070 // called blindly. For example, `to_string()` for the character 'c' returns
1071 // "'\u{63}'"; there is no way for the user to know whether the source text
1072 // was 'c' or whether it was '\u{63}'.
1073 #[unstable(feature = "proc_macro_span", issue = "54725")]
1074 pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
1075 // HACK(eddyb) something akin to `Option::cloned`, but for `Bound<&T>`.
1076 fn cloned_bound<T: Clone>(bound: Bound<&T>) -> Bound<T> {
1078 Bound::Included(x) => Bound::Included(x.clone()),
1079 Bound::Excluded(x) => Bound::Excluded(x.clone()),
1080 Bound::Unbounded => Bound::Unbounded,
1084 self.0.subspan(cloned_bound(range.start_bound()), cloned_bound(range.end_bound())).map(Span)
1088 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
1089 // based on it (the reverse of the usual relationship between the two).
1090 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
1091 impl ToString for Literal {
1092 fn to_string(&self) -> String {
1093 TokenStream::from(TokenTree::from(self.clone())).to_string()
1097 /// Prints the literal as a string that should be losslessly convertible
1098 /// back into the same literal (except for possible rounding for floating point literals).
1099 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1100 impl fmt::Display for Literal {
1101 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1102 f.write_str(&self.to_string())
1106 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1107 impl fmt::Debug for Literal {
1108 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1109 // FIXME(eddyb) `Literal` should not expose internal `Debug` impls.