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)]
24 #![feature(decl_macro)]
25 #![feature(extern_types)]
26 #![feature(in_band_lifetimes)]
27 #![cfg_attr(not(bootstrap), feature(negative_impls))]
28 #![feature(optin_builtin_traits)]
29 #![feature(rustc_attrs)]
30 #![cfg_attr(bootstrap, feature(specialization))]
31 #![cfg_attr(not(bootstrap), feature(min_specialization))]
32 #![recursion_limit = "256"]
34 #[unstable(feature = "proc_macro_internals", issue = "27812")]
40 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
41 pub use diagnostic::{Diagnostic, Level, MultiSpan};
43 use std::ops::{Bound, RangeBounds};
44 use std::path::PathBuf;
45 use std::str::FromStr;
46 use std::{error, fmt, iter, mem};
48 /// Determines whether proc_macro has been made accessible to the currently
51 /// The proc_macro crate is only intended for use inside the implementation of
52 /// procedural macros. All the functions in this crate panic if invoked from
53 /// outside of a procedural macro, such as from a build script or unit test or
54 /// ordinary Rust binary.
56 /// With consideration for Rust libraries that are designed to support both
57 /// macro and non-macro use cases, `proc_macro::is_available()` provides a
58 /// non-panicking way to detect whether the infrastructure required to use the
59 /// API of proc_macro is presently available. Returns true if invoked from
60 /// inside of a procedural macro, false if invoked from any other binary.
61 #[unstable(feature = "proc_macro_is_available", issue = "71436")]
62 pub fn is_available() -> bool {
63 bridge::Bridge::is_available()
66 /// The main type provided by this crate, representing an abstract stream of
67 /// tokens, or, more specifically, a sequence of token trees.
68 /// The type provide interfaces for iterating over those token trees and, conversely,
69 /// collecting a number of token trees into one stream.
71 /// This is both the input and output of `#[proc_macro]`, `#[proc_macro_attribute]`
72 /// and `#[proc_macro_derive]` definitions.
73 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
75 pub struct TokenStream(bridge::client::TokenStream);
77 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
78 impl !Send for TokenStream {}
79 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
80 impl !Sync for TokenStream {}
82 /// Error returned from `TokenStream::from_str`.
83 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
89 #[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
90 impl fmt::Display for LexError {
91 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
92 f.write_str("cannot parse string into token stream")
96 #[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
97 impl error::Error for LexError {}
99 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
100 impl !Send for LexError {}
101 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
102 impl !Sync for LexError {}
105 /// Returns an empty `TokenStream` containing no token trees.
106 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
107 pub fn new() -> TokenStream {
108 TokenStream(bridge::client::TokenStream::new())
111 /// Checks if this `TokenStream` is empty.
112 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
113 pub fn is_empty(&self) -> bool {
118 /// Attempts to break the string into tokens and parse those tokens into a token stream.
119 /// May fail for a number of reasons, for example, if the string contains unbalanced delimiters
120 /// or characters not existing in the language.
121 /// All tokens in the parsed stream get `Span::call_site()` spans.
123 /// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to
124 /// change these errors into `LexError`s later.
125 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
126 impl FromStr for TokenStream {
129 fn from_str(src: &str) -> Result<TokenStream, LexError> {
130 Ok(TokenStream(bridge::client::TokenStream::from_str(src)))
134 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
135 // based on it (the reverse of the usual relationship between the two).
136 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
137 impl ToString for TokenStream {
138 fn to_string(&self) -> String {
143 /// Prints the token stream as a string that is supposed to be losslessly convertible back
144 /// into the same token stream (modulo spans), except for possibly `TokenTree::Group`s
145 /// with `Delimiter::None` delimiters and negative numeric literals.
146 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
147 impl fmt::Display for TokenStream {
148 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
149 f.write_str(&self.to_string())
153 /// Prints token in a form convenient for debugging.
154 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
155 impl fmt::Debug for TokenStream {
156 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
157 f.write_str("TokenStream ")?;
158 f.debug_list().entries(self.clone()).finish()
162 #[unstable(feature = "proc_macro_quote", issue = "54722")]
163 pub use quote::{quote, quote_span};
165 /// Creates a token stream containing a single token tree.
166 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
167 impl From<TokenTree> for TokenStream {
168 fn from(tree: TokenTree) -> TokenStream {
169 TokenStream(bridge::client::TokenStream::from_token_tree(match tree {
170 TokenTree::Group(tt) => bridge::TokenTree::Group(tt.0),
171 TokenTree::Punct(tt) => bridge::TokenTree::Punct(tt.0),
172 TokenTree::Ident(tt) => bridge::TokenTree::Ident(tt.0),
173 TokenTree::Literal(tt) => bridge::TokenTree::Literal(tt.0),
178 /// Collects a number of token trees into a single stream.
179 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
180 impl iter::FromIterator<TokenTree> for TokenStream {
181 fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self {
182 trees.into_iter().map(TokenStream::from).collect()
186 /// A "flattening" operation on token streams, collects token trees
187 /// from multiple token streams into a single stream.
188 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
189 impl iter::FromIterator<TokenStream> for TokenStream {
190 fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
191 let mut builder = bridge::client::TokenStreamBuilder::new();
192 streams.into_iter().for_each(|stream| builder.push(stream.0));
193 TokenStream(builder.build())
197 #[stable(feature = "token_stream_extend", since = "1.30.0")]
198 impl Extend<TokenTree> for TokenStream {
199 fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) {
200 self.extend(trees.into_iter().map(TokenStream::from));
204 #[stable(feature = "token_stream_extend", since = "1.30.0")]
205 impl Extend<TokenStream> for TokenStream {
206 fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
207 // FIXME(eddyb) Use an optimized implementation if/when possible.
208 *self = iter::once(mem::replace(self, Self::new())).chain(streams).collect();
212 /// Public implementation details for the `TokenStream` type, such as iterators.
213 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
214 pub mod token_stream {
215 use crate::{bridge, Group, Ident, Literal, Punct, TokenStream, TokenTree};
217 /// An iterator over `TokenStream`'s `TokenTree`s.
218 /// The iteration is "shallow", e.g., the iterator doesn't recurse into delimited groups,
219 /// and returns whole groups as token trees.
221 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
222 pub struct IntoIter(bridge::client::TokenStreamIter);
224 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
225 impl Iterator for IntoIter {
226 type Item = TokenTree;
228 fn next(&mut self) -> Option<TokenTree> {
229 self.0.next().map(|tree| match tree {
230 bridge::TokenTree::Group(tt) => TokenTree::Group(Group(tt)),
231 bridge::TokenTree::Punct(tt) => TokenTree::Punct(Punct(tt)),
232 bridge::TokenTree::Ident(tt) => TokenTree::Ident(Ident(tt)),
233 bridge::TokenTree::Literal(tt) => TokenTree::Literal(Literal(tt)),
238 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
239 impl IntoIterator for TokenStream {
240 type Item = TokenTree;
241 type IntoIter = IntoIter;
243 fn into_iter(self) -> IntoIter {
244 IntoIter(self.0.into_iter())
249 /// `quote!(..)` accepts arbitrary tokens and expands into a `TokenStream` describing the input.
250 /// For example, `quote!(a + b)` will produce a expression, that, when evaluated, constructs
251 /// the `TokenStream` `[Ident("a"), Punct('+', Alone), Ident("b")]`.
253 /// Unquoting is done with `$`, and works by taking the single next ident as the unquoted term.
254 /// To quote `$` itself, use `$$`.
255 #[unstable(feature = "proc_macro_quote", issue = "54722")]
256 #[allow_internal_unstable(proc_macro_def_site)]
257 #[rustc_builtin_macro]
258 pub macro quote($($t:tt)*) {
259 /* compiler built-in */
262 #[unstable(feature = "proc_macro_internals", issue = "27812")]
266 /// A region of source code, along with macro expansion information.
267 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
268 #[derive(Copy, Clone)]
269 pub struct Span(bridge::client::Span);
271 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
272 impl !Send for Span {}
273 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
274 impl !Sync for Span {}
276 macro_rules! diagnostic_method {
277 ($name:ident, $level:expr) => (
278 /// Creates a new `Diagnostic` with the given `message` at the span
280 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
281 pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic {
282 Diagnostic::spanned(self, $level, message)
288 /// A span that resolves at the macro definition site.
289 #[unstable(feature = "proc_macro_def_site", issue = "54724")]
290 pub fn def_site() -> Span {
291 Span(bridge::client::Span::def_site())
294 /// The span of the invocation of the current procedural macro.
295 /// Identifiers created with this span will be resolved as if they were written
296 /// directly at the macro call location (call-site hygiene) and other code
297 /// at the macro call site will be able to refer to them as well.
298 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
299 pub fn call_site() -> Span {
300 Span(bridge::client::Span::call_site())
303 /// A span that represents `macro_rules` hygiene, and sometimes resolves at the macro
304 /// definition site (local variables, labels, `$crate`) and sometimes at the macro
305 /// call site (everything else).
306 /// The span location is taken from the call-site.
307 #[unstable(feature = "proc_macro_mixed_site", issue = "65049")]
308 pub fn mixed_site() -> Span {
309 Span(bridge::client::Span::mixed_site())
312 /// The original source file into which this span points.
313 #[unstable(feature = "proc_macro_span", issue = "54725")]
314 pub fn source_file(&self) -> SourceFile {
315 SourceFile(self.0.source_file())
318 /// The `Span` for the tokens in the previous macro expansion from which
319 /// `self` was generated from, if any.
320 #[unstable(feature = "proc_macro_span", issue = "54725")]
321 pub fn parent(&self) -> Option<Span> {
322 self.0.parent().map(Span)
325 /// The span for the origin source code that `self` was generated from. If
326 /// this `Span` wasn't generated from other macro expansions then the return
327 /// value is the same as `*self`.
328 #[unstable(feature = "proc_macro_span", issue = "54725")]
329 pub fn source(&self) -> Span {
330 Span(self.0.source())
333 /// Gets the starting line/column in the source file for this span.
334 #[unstable(feature = "proc_macro_span", issue = "54725")]
335 pub fn start(&self) -> LineColumn {
339 /// Gets the ending line/column in the source file for this span.
340 #[unstable(feature = "proc_macro_span", issue = "54725")]
341 pub fn end(&self) -> LineColumn {
345 /// Creates a new span encompassing `self` and `other`.
347 /// Returns `None` if `self` and `other` are from different files.
348 #[unstable(feature = "proc_macro_span", issue = "54725")]
349 pub fn join(&self, other: Span) -> Option<Span> {
350 self.0.join(other.0).map(Span)
353 /// Creates a new span with the same line/column information as `self` but
354 /// that resolves symbols as though it were at `other`.
355 #[unstable(feature = "proc_macro_span", issue = "54725")]
356 pub fn resolved_at(&self, other: Span) -> Span {
357 Span(self.0.resolved_at(other.0))
360 /// Creates a new span with the same name resolution behavior as `self` but
361 /// with the line/column information of `other`.
362 #[unstable(feature = "proc_macro_span", issue = "54725")]
363 pub fn located_at(&self, other: Span) -> Span {
364 other.resolved_at(*self)
367 /// Compares to spans to see if they're equal.
368 #[unstable(feature = "proc_macro_span", issue = "54725")]
369 pub fn eq(&self, other: &Span) -> bool {
373 /// Returns the source text behind a span. This preserves the original source
374 /// code, including spaces and comments. It only returns a result if the span
375 /// corresponds to real source code.
377 /// Note: The observable result of a macro should only rely on the tokens and
378 /// not on this source text. The result of this function is a best effort to
379 /// be used for diagnostics only.
380 #[unstable(feature = "proc_macro_span", issue = "54725")]
381 pub fn source_text(&self) -> Option<String> {
385 diagnostic_method!(error, Level::Error);
386 diagnostic_method!(warning, Level::Warning);
387 diagnostic_method!(note, Level::Note);
388 diagnostic_method!(help, Level::Help);
391 /// Prints a span in a form convenient for debugging.
392 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
393 impl fmt::Debug for Span {
394 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
399 /// A line-column pair representing the start or end of a `Span`.
400 #[unstable(feature = "proc_macro_span", issue = "54725")]
401 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
402 pub struct LineColumn {
403 /// The 1-indexed line in the source file on which the span starts or ends (inclusive).
404 #[unstable(feature = "proc_macro_span", issue = "54725")]
406 /// The 0-indexed column (in UTF-8 characters) in the source file on which
407 /// the span starts or ends (inclusive).
408 #[unstable(feature = "proc_macro_span", issue = "54725")]
412 #[unstable(feature = "proc_macro_span", issue = "54725")]
413 impl !Send for LineColumn {}
414 #[unstable(feature = "proc_macro_span", issue = "54725")]
415 impl !Sync for LineColumn {}
417 /// The source file of a given `Span`.
418 #[unstable(feature = "proc_macro_span", issue = "54725")]
420 pub struct SourceFile(bridge::client::SourceFile);
423 /// Gets the path to this source file.
426 /// If the code span associated with this `SourceFile` was generated by an external macro, this
427 /// macro, this may not be an actual path on the filesystem. Use [`is_real`] to check.
429 /// Also note that even if `is_real` returns `true`, if `--remap-path-prefix` was passed on
430 /// the command line, the path as given may not actually be valid.
432 /// [`is_real`]: #method.is_real
433 #[unstable(feature = "proc_macro_span", issue = "54725")]
434 pub fn path(&self) -> PathBuf {
435 PathBuf::from(self.0.path())
438 /// Returns `true` if this source file is a real source file, and not generated by an external
439 /// macro's expansion.
440 #[unstable(feature = "proc_macro_span", issue = "54725")]
441 pub fn is_real(&self) -> bool {
442 // This is a hack until intercrate spans are implemented and we can have real source files
443 // for spans generated in external macros.
444 // https://github.com/rust-lang/rust/pull/43604#issuecomment-333334368
449 #[unstable(feature = "proc_macro_span", issue = "54725")]
450 impl fmt::Debug for SourceFile {
451 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
452 f.debug_struct("SourceFile")
453 .field("path", &self.path())
454 .field("is_real", &self.is_real())
459 #[unstable(feature = "proc_macro_span", issue = "54725")]
460 impl PartialEq for SourceFile {
461 fn eq(&self, other: &Self) -> bool {
466 #[unstable(feature = "proc_macro_span", issue = "54725")]
467 impl Eq for SourceFile {}
469 /// A single token or a delimited sequence of token trees (e.g., `[1, (), ..]`).
470 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
473 /// A token stream surrounded by bracket delimiters.
474 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
475 Group(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Group),
477 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
478 Ident(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Ident),
479 /// A single punctuation character (`+`, `,`, `$`, etc.).
480 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
481 Punct(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Punct),
482 /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
483 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
484 Literal(#[stable(feature = "proc_macro_lib2", since = "1.29.0")] Literal),
487 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
488 impl !Send for TokenTree {}
489 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
490 impl !Sync for TokenTree {}
493 /// Returns the span of this tree, delegating to the `span` method of
494 /// the contained token or a delimited stream.
495 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
496 pub fn span(&self) -> Span {
498 TokenTree::Group(ref t) => t.span(),
499 TokenTree::Ident(ref t) => t.span(),
500 TokenTree::Punct(ref t) => t.span(),
501 TokenTree::Literal(ref t) => t.span(),
505 /// Configures the span for *only this token*.
507 /// Note that if this token is a `Group` then this method will not configure
508 /// the span of each of the internal tokens, this will simply delegate to
509 /// the `set_span` method of each variant.
510 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
511 pub fn set_span(&mut self, span: Span) {
513 TokenTree::Group(ref mut t) => t.set_span(span),
514 TokenTree::Ident(ref mut t) => t.set_span(span),
515 TokenTree::Punct(ref mut t) => t.set_span(span),
516 TokenTree::Literal(ref mut t) => t.set_span(span),
521 /// Prints token tree in a form convenient for debugging.
522 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
523 impl fmt::Debug for TokenTree {
524 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
525 // Each of these has the name in the struct type in the derived debug,
526 // so don't bother with an extra layer of indirection
528 TokenTree::Group(ref tt) => tt.fmt(f),
529 TokenTree::Ident(ref tt) => tt.fmt(f),
530 TokenTree::Punct(ref tt) => tt.fmt(f),
531 TokenTree::Literal(ref tt) => tt.fmt(f),
536 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
537 impl From<Group> for TokenTree {
538 fn from(g: Group) -> TokenTree {
543 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
544 impl From<Ident> for TokenTree {
545 fn from(g: Ident) -> TokenTree {
550 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
551 impl From<Punct> for TokenTree {
552 fn from(g: Punct) -> TokenTree {
557 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
558 impl From<Literal> for TokenTree {
559 fn from(g: Literal) -> TokenTree {
560 TokenTree::Literal(g)
564 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
565 // based on it (the reverse of the usual relationship between the two).
566 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
567 impl ToString for TokenTree {
568 fn to_string(&self) -> String {
570 TokenTree::Group(ref t) => t.to_string(),
571 TokenTree::Ident(ref t) => t.to_string(),
572 TokenTree::Punct(ref t) => t.to_string(),
573 TokenTree::Literal(ref t) => t.to_string(),
578 /// Prints the token tree as a string that is supposed to be losslessly convertible back
579 /// into the same token tree (modulo spans), except for possibly `TokenTree::Group`s
580 /// with `Delimiter::None` delimiters and negative numeric literals.
581 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
582 impl fmt::Display for TokenTree {
583 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
584 f.write_str(&self.to_string())
588 /// A delimited token stream.
590 /// A `Group` internally contains a `TokenStream` which is surrounded by `Delimiter`s.
592 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
593 pub struct Group(bridge::client::Group);
595 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
596 impl !Send for Group {}
597 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
598 impl !Sync for Group {}
600 /// Describes how a sequence of token trees is delimited.
601 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
602 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
605 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
608 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
611 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
614 /// An implicit delimiter, that may, for example, appear around tokens coming from a
615 /// "macro variable" `$var`. It is important to preserve operator priorities in cases like
616 /// `$var * 3` where `$var` is `1 + 2`.
617 /// Implicit delimiters may not survive roundtrip of a token stream through a string.
618 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
623 /// Creates a new `Group` with the given delimiter and token stream.
625 /// This constructor will set the span for this group to
626 /// `Span::call_site()`. To change the span you can use the `set_span`
628 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
629 pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group {
630 Group(bridge::client::Group::new(delimiter, stream.0))
633 /// Returns the delimiter of this `Group`
634 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
635 pub fn delimiter(&self) -> Delimiter {
639 /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
641 /// Note that the returned token stream does not include the delimiter
643 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
644 pub fn stream(&self) -> TokenStream {
645 TokenStream(self.0.stream())
648 /// Returns the span for the delimiters of this token stream, spanning the
652 /// pub fn span(&self) -> Span {
655 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
656 pub fn span(&self) -> Span {
660 /// Returns the span pointing to the opening delimiter of this group.
663 /// pub fn span_open(&self) -> Span {
666 #[unstable(feature = "proc_macro_span", issue = "54725")]
667 pub fn span_open(&self) -> Span {
668 Span(self.0.span_open())
671 /// Returns the span pointing to the closing delimiter of this group.
674 /// pub fn span_close(&self) -> Span {
677 #[unstable(feature = "proc_macro_span", issue = "54725")]
678 pub fn span_close(&self) -> Span {
679 Span(self.0.span_close())
682 /// Configures the span for this `Group`'s delimiters, but not its internal
685 /// This method will **not** set the span of all the internal tokens spanned
686 /// by this group, but rather it will only set the span of the delimiter
687 /// tokens at the level of the `Group`.
688 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
689 pub fn set_span(&mut self, span: Span) {
690 self.0.set_span(span.0);
694 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
695 // based on it (the reverse of the usual relationship between the two).
696 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
697 impl ToString for Group {
698 fn to_string(&self) -> String {
699 TokenStream::from(TokenTree::from(self.clone())).to_string()
703 /// Prints the group as a string that should be losslessly convertible back
704 /// into the same group (modulo spans), except for possibly `TokenTree::Group`s
705 /// with `Delimiter::None` delimiters.
706 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
707 impl fmt::Display for Group {
708 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
709 f.write_str(&self.to_string())
713 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
714 impl fmt::Debug for Group {
715 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
716 f.debug_struct("Group")
717 .field("delimiter", &self.delimiter())
718 .field("stream", &self.stream())
719 .field("span", &self.span())
724 /// An `Punct` is an single punctuation character like `+`, `-` or `#`.
726 /// Multi-character operators like `+=` are represented as two instances of `Punct` with different
727 /// forms of `Spacing` returned.
728 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
730 pub struct Punct(bridge::client::Punct);
732 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
733 impl !Send for Punct {}
734 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
735 impl !Sync for Punct {}
737 /// Whether an `Punct` is followed immediately by another `Punct` or
738 /// followed by another token or whitespace.
739 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
740 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
742 /// e.g., `+` is `Alone` in `+ =`, `+ident` or `+()`.
743 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
745 /// e.g., `+` is `Joint` in `+=` or `'#`.
746 /// Additionally, single quote `'` can join with identifiers to form lifetimes `'ident`.
747 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
752 /// Creates a new `Punct` from the given character and spacing.
753 /// The `ch` argument must be a valid punctuation character permitted by the language,
754 /// otherwise the function will panic.
756 /// The returned `Punct` will have the default span of `Span::call_site()`
757 /// which can be further configured with the `set_span` method below.
758 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
759 pub fn new(ch: char, spacing: Spacing) -> Punct {
760 Punct(bridge::client::Punct::new(ch, spacing))
763 /// Returns the value of this punctuation character as `char`.
764 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
765 pub fn as_char(&self) -> char {
769 /// Returns the spacing of this punctuation character, indicating whether it's immediately
770 /// followed by another `Punct` in the token stream, so they can potentially be combined into
771 /// a multi-character operator (`Joint`), or it's followed by some other token or whitespace
772 /// (`Alone`) so the operator has certainly ended.
773 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
774 pub fn spacing(&self) -> Spacing {
778 /// Returns the span for this punctuation character.
779 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
780 pub fn span(&self) -> Span {
784 /// Configure the span for this punctuation character.
785 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
786 pub fn set_span(&mut self, span: Span) {
787 self.0 = self.0.with_span(span.0);
791 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
792 // based on it (the reverse of the usual relationship between the two).
793 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
794 impl ToString for Punct {
795 fn to_string(&self) -> String {
796 TokenStream::from(TokenTree::from(self.clone())).to_string()
800 /// Prints the punctuation character as a string that should be losslessly convertible
801 /// back into the same character.
802 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
803 impl fmt::Display for Punct {
804 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
805 f.write_str(&self.to_string())
809 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
810 impl fmt::Debug for Punct {
811 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
812 f.debug_struct("Punct")
813 .field("ch", &self.as_char())
814 .field("spacing", &self.spacing())
815 .field("span", &self.span())
820 /// An identifier (`ident`).
822 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
823 pub struct Ident(bridge::client::Ident);
826 /// Creates a new `Ident` with the given `string` as well as the specified
828 /// The `string` argument must be a valid identifier permitted by the
829 /// language, otherwise the function will panic.
831 /// Note that `span`, currently in rustc, configures the hygiene information
832 /// for this identifier.
834 /// As of this time `Span::call_site()` explicitly opts-in to "call-site" hygiene
835 /// meaning that identifiers created with this span will be resolved as if they were written
836 /// directly at the location of the macro call, and other code at the macro call site will be
837 /// able to refer to them as well.
839 /// Later spans like `Span::def_site()` will allow to opt-in to "definition-site" hygiene
840 /// meaning that identifiers created with this span will be resolved at the location of the
841 /// macro definition and other code at the macro call site will not be able to refer to them.
843 /// Due to the current importance of hygiene this constructor, unlike other
844 /// tokens, requires a `Span` to be specified at construction.
845 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
846 pub fn new(string: &str, span: Span) -> Ident {
847 Ident(bridge::client::Ident::new(string, span.0, false))
850 /// Same as `Ident::new`, but creates a raw identifier (`r#ident`).
851 #[unstable(feature = "proc_macro_raw_ident", issue = "54723")]
852 pub fn new_raw(string: &str, span: Span) -> Ident {
853 Ident(bridge::client::Ident::new(string, span.0, true))
856 /// Returns the span of this `Ident`, encompassing the entire string returned
858 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
859 pub fn span(&self) -> Span {
863 /// Configures the span of this `Ident`, possibly changing its hygiene context.
864 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
865 pub fn set_span(&mut self, span: Span) {
866 self.0 = self.0.with_span(span.0);
870 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
871 // based on it (the reverse of the usual relationship between the two).
872 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
873 impl ToString for Ident {
874 fn to_string(&self) -> String {
875 TokenStream::from(TokenTree::from(self.clone())).to_string()
879 /// Prints the identifier as a string that should be losslessly convertible
880 /// back into the same identifier.
881 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
882 impl fmt::Display for Ident {
883 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
884 f.write_str(&self.to_string())
888 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
889 impl fmt::Debug for Ident {
890 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
891 f.debug_struct("Ident")
892 .field("ident", &self.to_string())
893 .field("span", &self.span())
898 /// A literal string (`"hello"`), byte string (`b"hello"`),
899 /// character (`'a'`), byte character (`b'a'`), an integer or floating point number
900 /// with or without a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
901 /// Boolean literals like `true` and `false` do not belong here, they are `Ident`s.
903 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
904 pub struct Literal(bridge::client::Literal);
906 macro_rules! suffixed_int_literals {
907 ($($name:ident => $kind:ident,)*) => ($(
908 /// Creates a new suffixed integer literal with the specified value.
910 /// This function will create an integer like `1u32` where the integer
911 /// value specified is the first part of the token and the integral is
912 /// also suffixed at the end.
913 /// Literals created from negative numbers may not survive round-trips through
914 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
916 /// Literals created through this method have the `Span::call_site()`
917 /// span by default, which can be configured with the `set_span` method
919 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
920 pub fn $name(n: $kind) -> Literal {
921 Literal(bridge::client::Literal::typed_integer(&n.to_string(), stringify!($kind)))
926 macro_rules! unsuffixed_int_literals {
927 ($($name:ident => $kind:ident,)*) => ($(
928 /// Creates a new unsuffixed integer literal with the specified value.
930 /// This function will create an integer like `1` where the integer
931 /// value specified is the first part of the token. No suffix is
932 /// specified on this token, meaning that invocations like
933 /// `Literal::i8_unsuffixed(1)` are equivalent to
934 /// `Literal::u32_unsuffixed(1)`.
935 /// Literals created from negative numbers may not survive rountrips through
936 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
938 /// Literals created through this method have the `Span::call_site()`
939 /// span by default, which can be configured with the `set_span` method
941 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
942 pub fn $name(n: $kind) -> Literal {
943 Literal(bridge::client::Literal::integer(&n.to_string()))
949 suffixed_int_literals! {
954 u128_suffixed => u128,
955 usize_suffixed => usize,
960 i128_suffixed => i128,
961 isize_suffixed => isize,
964 unsuffixed_int_literals! {
966 u16_unsuffixed => u16,
967 u32_unsuffixed => u32,
968 u64_unsuffixed => u64,
969 u128_unsuffixed => u128,
970 usize_unsuffixed => usize,
972 i16_unsuffixed => i16,
973 i32_unsuffixed => i32,
974 i64_unsuffixed => i64,
975 i128_unsuffixed => i128,
976 isize_unsuffixed => isize,
979 /// Creates a new unsuffixed floating-point literal.
981 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
982 /// the float's value is emitted directly into the token but no suffix is
983 /// used, so it may be inferred to be a `f64` later in the compiler.
984 /// Literals created from negative numbers may not survive rountrips through
985 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
989 /// This function requires that the specified float is finite, for
990 /// example if it is infinity or NaN this function will panic.
991 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
992 pub fn f32_unsuffixed(n: f32) -> Literal {
994 panic!("Invalid float literal {}", n);
996 Literal(bridge::client::Literal::float(&n.to_string()))
999 /// Creates a new suffixed floating-point literal.
1001 /// This constructor will create a literal like `1.0f32` where the value
1002 /// specified is the preceding part of the token and `f32` is the suffix of
1003 /// the token. This token will always be inferred to be an `f32` in the
1005 /// Literals created from negative numbers may not survive rountrips through
1006 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1010 /// This function requires that the specified float is finite, for
1011 /// example if it is infinity or NaN this function will panic.
1012 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1013 pub fn f32_suffixed(n: f32) -> Literal {
1015 panic!("Invalid float literal {}", n);
1017 Literal(bridge::client::Literal::f32(&n.to_string()))
1020 /// Creates a new unsuffixed floating-point literal.
1022 /// This constructor is similar to those like `Literal::i8_unsuffixed` where
1023 /// the float's value is emitted directly into the token but no suffix is
1024 /// used, so it may be inferred to be a `f64` later in the compiler.
1025 /// Literals created from negative numbers may not survive rountrips through
1026 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1030 /// This function requires that the specified float is finite, for
1031 /// example if it is infinity or NaN this function will panic.
1032 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1033 pub fn f64_unsuffixed(n: f64) -> Literal {
1035 panic!("Invalid float literal {}", n);
1037 Literal(bridge::client::Literal::float(&n.to_string()))
1040 /// Creates a new suffixed floating-point literal.
1042 /// This constructor will create a literal like `1.0f64` where the value
1043 /// specified is the preceding part of the token and `f64` is the suffix of
1044 /// the token. This token will always be inferred to be an `f64` in the
1046 /// Literals created from negative numbers may not survive rountrips through
1047 /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
1051 /// This function requires that the specified float is finite, for
1052 /// example if it is infinity or NaN this function will panic.
1053 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1054 pub fn f64_suffixed(n: f64) -> Literal {
1056 panic!("Invalid float literal {}", n);
1058 Literal(bridge::client::Literal::f64(&n.to_string()))
1062 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1063 pub fn string(string: &str) -> Literal {
1064 Literal(bridge::client::Literal::string(string))
1067 /// Character literal.
1068 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1069 pub fn character(ch: char) -> Literal {
1070 Literal(bridge::client::Literal::character(ch))
1073 /// Byte string literal.
1074 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1075 pub fn byte_string(bytes: &[u8]) -> Literal {
1076 Literal(bridge::client::Literal::byte_string(bytes))
1079 /// Returns the span encompassing this literal.
1080 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1081 pub fn span(&self) -> Span {
1085 /// Configures the span associated for this literal.
1086 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1087 pub fn set_span(&mut self, span: Span) {
1088 self.0.set_span(span.0);
1091 /// Returns a `Span` that is a subset of `self.span()` containing only the
1092 /// source bytes in range `range`. Returns `None` if the would-be trimmed
1093 /// span is outside the bounds of `self`.
1094 // FIXME(SergioBenitez): check that the byte range starts and ends at a
1095 // UTF-8 boundary of the source. otherwise, it's likely that a panic will
1096 // occur elsewhere when the source text is printed.
1097 // FIXME(SergioBenitez): there is no way for the user to know what
1098 // `self.span()` actually maps to, so this method can currently only be
1099 // called blindly. For example, `to_string()` for the character 'c' returns
1100 // "'\u{63}'"; there is no way for the user to know whether the source text
1101 // was 'c' or whether it was '\u{63}'.
1102 #[unstable(feature = "proc_macro_span", issue = "54725")]
1103 pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
1104 // HACK(eddyb) something akin to `Option::cloned`, but for `Bound<&T>`.
1105 fn cloned_bound<T: Clone>(bound: Bound<&T>) -> Bound<T> {
1107 Bound::Included(x) => Bound::Included(x.clone()),
1108 Bound::Excluded(x) => Bound::Excluded(x.clone()),
1109 Bound::Unbounded => Bound::Unbounded,
1113 self.0.subspan(cloned_bound(range.start_bound()), cloned_bound(range.end_bound())).map(Span)
1117 // N.B., the bridge only provides `to_string`, implement `fmt::Display`
1118 // based on it (the reverse of the usual relationship between the two).
1119 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
1120 impl ToString for Literal {
1121 fn to_string(&self) -> String {
1122 TokenStream::from(TokenTree::from(self.clone())).to_string()
1126 /// Prints the literal as a string that should be losslessly convertible
1127 /// back into the same literal (except for possible rounding for floating point literals).
1128 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1129 impl fmt::Display for Literal {
1130 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1131 f.write_str(&self.to_string())
1135 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
1136 impl fmt::Debug for Literal {
1137 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1138 // FIXME(eddyb) `Literal` should not expose internal `Debug` impls.