1 // Copyright 2016 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! A support library for macro authors when defining new macros.
13 //! This library, provided by the standard distribution, provides the types
14 //! consumed in the interfaces of procedurally defined macro definitions.
15 //! Currently the primary use of this crate is to provide the ability to define
16 //! new custom derive modes through `#[proc_macro_derive]`.
18 //! Note that this crate is intentionally very bare-bones currently. The main
19 //! type, `TokenStream`, only supports `fmt::Display` and `FromStr`
20 //! implementations, indicating that it can only go to and come from a string.
21 //! This functionality is intended to be expanded over time as more surface
22 //! area for macro authors is stabilized.
24 //! See [the book](../book/first-edition/procedural-macros.html) for more.
26 #![stable(feature = "proc_macro_lib", since = "1.15.0")]
28 #![deny(missing_docs)]
29 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
30 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
31 html_root_url = "https://doc.rust-lang.org/nightly/",
32 html_playground_url = "https://play.rust-lang.org/",
33 issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
34 test(no_crate_inject, attr(deny(warnings))),
35 test(attr(allow(dead_code, deprecated, unused_variables, unused_mut))))]
37 #![feature(i128_type)]
38 #![feature(rustc_private)]
39 #![feature(staged_api)]
40 #![feature(lang_items)]
44 extern crate syntax_pos;
45 extern crate rustc_errors;
49 #[unstable(feature = "proc_macro", issue = "38356")]
50 pub use diagnostic::{Diagnostic, Level};
52 use std::{ascii, fmt, iter};
54 use std::str::FromStr;
57 use syntax::errors::DiagnosticBuilder;
58 use syntax::parse::{self, token};
59 use syntax::symbol::Symbol;
60 use syntax::tokenstream;
61 use syntax_pos::DUMMY_SP;
62 use syntax_pos::{FileMap, Pos, SyntaxContext, FileName};
63 use syntax_pos::hygiene::Mark;
65 /// The main type provided by this crate, representing an abstract stream of
68 /// This is both the input and output of `#[proc_macro_derive]` definitions.
69 /// Currently it's required to be a list of valid Rust items, but this
70 /// restriction may be lifted in the future.
72 /// The API of this type is intentionally bare-bones, but it'll be expanded over
74 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
75 #[derive(Clone, Debug)]
76 pub struct TokenStream(tokenstream::TokenStream);
78 /// Error returned from `TokenStream::from_str`.
79 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
85 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
86 impl FromStr for TokenStream {
89 fn from_str(src: &str) -> Result<TokenStream, LexError> {
90 __internal::with_sess(|(sess, mark)| {
91 let src = src.to_string();
92 let name = FileName::ProcMacroSourceCode;
93 let expn_info = mark.expn_info().unwrap();
94 let call_site = expn_info.call_site;
95 // notify the expansion info that it is unhygienic
96 let mark = Mark::fresh(mark);
97 mark.set_expn_info(expn_info);
98 let span = call_site.with_ctxt(call_site.ctxt().apply_mark(mark));
99 let stream = parse::parse_stream_from_source_str(name, src, sess, Some(span));
100 Ok(__internal::token_stream_wrap(stream))
105 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
106 impl fmt::Display for TokenStream {
107 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
112 /// `quote!(..)` accepts arbitrary tokens and expands into a `TokenStream` describing the input.
113 /// For example, `quote!(a + b)` will produce a expression, that, when evaluated, constructs
114 /// the `TokenStream` `[Word("a"), Op('+', Alone), Word("b")]`.
116 /// Unquoting is done with `$`, and works by taking the single next ident as the unquoted term.
117 /// To quote `$` itself, use `$$`.
118 #[unstable(feature = "proc_macro", issue = "38356")]
120 macro_rules! quote { () => {} }
122 #[unstable(feature = "proc_macro_internals", issue = "27812")]
126 #[unstable(feature = "proc_macro", issue = "38356")]
127 impl From<TokenTree> for TokenStream {
128 fn from(tree: TokenTree) -> TokenStream {
129 TokenStream(tree.to_internal())
133 #[unstable(feature = "proc_macro", issue = "38356")]
134 impl From<TokenNode> for TokenStream {
135 fn from(kind: TokenNode) -> TokenStream {
136 TokenTree::from(kind).into()
140 #[unstable(feature = "proc_macro", issue = "38356")]
141 impl<T: Into<TokenStream>> iter::FromIterator<T> for TokenStream {
142 fn from_iter<I: IntoIterator<Item = T>>(streams: I) -> Self {
143 let mut builder = tokenstream::TokenStreamBuilder::new();
144 for stream in streams {
145 builder.push(stream.into().0);
147 TokenStream(builder.build())
151 #[unstable(feature = "proc_macro", issue = "38356")]
152 impl IntoIterator for TokenStream {
153 type Item = TokenTree;
154 type IntoIter = TokenTreeIter;
156 fn into_iter(self) -> TokenTreeIter {
157 TokenTreeIter { cursor: self.0.trees(), next: None }
162 /// Returns an empty `TokenStream`.
163 #[unstable(feature = "proc_macro", issue = "38356")]
164 pub fn empty() -> TokenStream {
165 TokenStream(tokenstream::TokenStream::empty())
168 /// Checks if this `TokenStream` is empty.
169 #[unstable(feature = "proc_macro", issue = "38356")]
170 pub fn is_empty(&self) -> bool {
175 /// A region of source code, along with macro expansion information.
176 #[unstable(feature = "proc_macro", issue = "38356")]
177 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
178 pub struct Span(syntax_pos::Span);
181 /// A span that resolves at the macro definition site.
182 #[unstable(feature = "proc_macro", issue = "38356")]
183 pub fn def_site() -> Span {
184 ::__internal::with_sess(|(_, mark)| {
185 let call_site = mark.expn_info().unwrap().call_site;
186 Span(call_site.with_ctxt(SyntaxContext::empty().apply_mark(mark)))
191 /// Quote a `Span` into a `TokenStream`.
192 /// This is needed to implement a custom quoter.
193 #[unstable(feature = "proc_macro", issue = "38356")]
194 pub fn quote_span(span: Span) -> TokenStream {
195 quote::Quote::quote(span)
198 macro_rules! diagnostic_method {
199 ($name:ident, $level:expr) => (
200 /// Create a new `Diagnostic` with the given `message` at the span
202 #[unstable(feature = "proc_macro", issue = "38356")]
203 pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic {
204 Diagnostic::spanned(self, $level, message)
210 /// The span of the invocation of the current procedural macro.
211 #[unstable(feature = "proc_macro", issue = "38356")]
212 pub fn call_site() -> Span {
213 ::__internal::with_sess(|(_, mark)| Span(mark.expn_info().unwrap().call_site))
216 /// The original source file into which this span points.
217 #[unstable(feature = "proc_macro", issue = "38356")]
218 pub fn source_file(&self) -> SourceFile {
220 filemap: __internal::lookup_char_pos(self.0.lo()).file,
224 /// Get the starting line/column in the source file for this span.
225 #[unstable(feature = "proc_macro", issue = "38356")]
226 pub fn start(&self) -> LineColumn {
227 let loc = __internal::lookup_char_pos(self.0.lo());
230 column: loc.col.to_usize()
234 /// Get the ending line/column in the source file for this span.
235 #[unstable(feature = "proc_macro", issue = "38356")]
236 pub fn end(&self) -> LineColumn {
237 let loc = __internal::lookup_char_pos(self.0.hi());
240 column: loc.col.to_usize()
244 /// Create a new span encompassing `self` and `other`.
246 /// Returns `None` if `self` and `other` are from different files.
247 #[unstable(feature = "proc_macro", issue = "38356")]
248 pub fn join(&self, other: Span) -> Option<Span> {
249 let self_loc = __internal::lookup_char_pos(self.0.lo());
250 let other_loc = __internal::lookup_char_pos(self.0.lo());
252 if self_loc.file.name != other_loc.file.name { return None }
254 Some(Span(self.0.to(other.0)))
257 /// Creates a new span with the same line/column information as `self` but
258 /// that resolves symbols as though it were at `other`.
259 #[unstable(feature = "proc_macro", issue = "38356")]
260 pub fn resolved_at(&self, other: Span) -> Span {
261 Span(self.0.with_ctxt(other.0.ctxt()))
264 /// Creates a new span with the same name resolution behavior as `self` but
265 /// with the line/column information of `other`.
266 #[unstable(feature = "proc_macro", issue = "38356")]
267 pub fn located_at(&self, other: Span) -> Span {
268 other.resolved_at(*self)
271 diagnostic_method!(error, Level::Error);
272 diagnostic_method!(warning, Level::Warning);
273 diagnostic_method!(note, Level::Note);
274 diagnostic_method!(help, Level::Help);
277 /// A line-column pair representing the start or end of a `Span`.
278 #[unstable(feature = "proc_macro", issue = "38356")]
279 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
280 pub struct LineColumn {
281 /// The 1-indexed line in the source file on which the span starts or ends (inclusive).
282 #[unstable(feature = "proc_macro", issue = "38356")]
284 /// The 0-indexed column (in UTF-8 characters) in the source file on which
285 /// the span starts or ends (inclusive).
286 #[unstable(feature = "proc_macro", issue = "38356")]
290 /// The source file of a given `Span`.
291 #[unstable(feature = "proc_macro", issue = "38356")]
293 pub struct SourceFile {
294 filemap: Rc<FileMap>,
298 /// Get the path to this source file.
301 /// If the code span associated with this `SourceFile` was generated by an external macro, this
302 /// may not be an actual path on the filesystem. Use [`is_real`] to check.
304 /// Also note that even if `is_real` returns `true`, if `-Z remap-path-prefix-*` was passed on
305 /// the command line, the path as given may not actually be valid.
307 /// [`is_real`]: #method.is_real
308 # [unstable(feature = "proc_macro", issue = "38356")]
309 pub fn path(&self) -> &FileName {
313 /// Returns `true` if this source file is a real source file, and not generated by an external
314 /// macro's expansion.
315 # [unstable(feature = "proc_macro", issue = "38356")]
316 pub fn is_real(&self) -> bool {
317 // This is a hack until intercrate spans are implemented and we can have real source files
318 // for spans generated in external macros.
319 // https://github.com/rust-lang/rust/pull/43604#issuecomment-333334368
320 self.filemap.is_real_file()
324 #[unstable(feature = "proc_macro", issue = "38356")]
325 impl AsRef<FileName> for SourceFile {
326 fn as_ref(&self) -> &FileName {
331 #[unstable(feature = "proc_macro", issue = "38356")]
332 impl fmt::Debug for SourceFile {
333 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
334 f.debug_struct("SourceFile")
335 .field("path", self.path())
336 .field("is_real", &self.is_real())
341 #[unstable(feature = "proc_macro", issue = "38356")]
342 impl PartialEq for SourceFile {
343 fn eq(&self, other: &Self) -> bool {
344 Rc::ptr_eq(&self.filemap, &other.filemap)
348 #[unstable(feature = "proc_macro", issue = "38356")]
349 impl Eq for SourceFile {}
351 #[unstable(feature = "proc_macro", issue = "38356")]
352 impl PartialEq<FileName> for SourceFile {
353 fn eq(&self, other: &FileName) -> bool {
354 self.as_ref() == other
358 /// A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`).
359 #[unstable(feature = "proc_macro", issue = "38356")]
360 #[derive(Clone, Debug)]
361 pub struct TokenTree {
362 /// The `TokenTree`'s span
364 /// Description of the `TokenTree`
368 #[unstable(feature = "proc_macro", issue = "38356")]
369 impl From<TokenNode> for TokenTree {
370 fn from(kind: TokenNode) -> TokenTree {
371 TokenTree { span: Span::def_site(), kind: kind }
375 #[unstable(feature = "proc_macro", issue = "38356")]
376 impl fmt::Display for TokenTree {
377 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
378 TokenStream::from(self.clone()).fmt(f)
382 /// Description of a `TokenTree`
383 #[derive(Clone, Debug)]
384 #[unstable(feature = "proc_macro", issue = "38356")]
386 /// A delimited tokenstream.
387 Group(Delimiter, TokenStream),
388 /// A unicode identifier.
390 /// A punctuation character (`+`, `,`, `$`, etc.).
392 /// A literal character (`'a'`), string (`"hello"`), or number (`2.3`).
396 /// Describes how a sequence of token trees is delimited.
397 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
398 #[unstable(feature = "proc_macro", issue = "38356")]
406 /// An implicit delimiter, e.g. `$var`, where $var is `...`.
410 /// An interned string.
411 #[derive(Copy, Clone, Debug)]
412 #[unstable(feature = "proc_macro", issue = "38356")]
413 pub struct Term(Symbol);
416 /// Intern a string into a `Term`.
417 #[unstable(feature = "proc_macro", issue = "38356")]
418 pub fn intern(string: &str) -> Term {
419 Term(Symbol::intern(string))
422 /// Get a reference to the interned string.
423 #[unstable(feature = "proc_macro", issue = "38356")]
424 pub fn as_str(&self) -> &str {
425 unsafe { &*(&*self.0.as_str() as *const str) }
429 /// Whether an `Op` is either followed immediately by another `Op` or followed by whitespace.
430 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
431 #[unstable(feature = "proc_macro", issue = "38356")]
433 /// e.g. `+` is `Alone` in `+ =`.
435 /// e.g. `+` is `Joint` in `+=`.
439 /// A literal character (`'a'`), string (`"hello"`), or number (`2.3`).
440 #[derive(Clone, Debug)]
441 #[unstable(feature = "proc_macro", issue = "38356")]
442 pub struct Literal(token::Token);
444 #[unstable(feature = "proc_macro", issue = "38356")]
445 impl fmt::Display for Literal {
446 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
447 TokenTree { kind: TokenNode::Literal(self.clone()), span: Span(DUMMY_SP) }.fmt(f)
451 macro_rules! int_literals {
452 ($($int_kind:ident),*) => {$(
454 #[unstable(feature = "proc_macro", issue = "38356")]
455 pub fn $int_kind(n: $int_kind) -> Literal {
456 Literal::typed_integer(n as i128, stringify!($int_kind))
463 #[unstable(feature = "proc_macro", issue = "38356")]
464 pub fn integer(n: i128) -> Literal {
465 Literal(token::Literal(token::Lit::Integer(Symbol::intern(&n.to_string())), None))
468 int_literals!(u8, i8, u16, i16, u32, i32, u64, i64, usize, isize);
469 fn typed_integer(n: i128, kind: &'static str) -> Literal {
470 Literal(token::Literal(token::Lit::Integer(Symbol::intern(&n.to_string())),
471 Some(Symbol::intern(kind))))
474 /// Floating point literal.
475 #[unstable(feature = "proc_macro", issue = "38356")]
476 pub fn float(n: f64) -> Literal {
478 panic!("Invalid float literal {}", n);
480 Literal(token::Literal(token::Lit::Float(Symbol::intern(&n.to_string())), None))
483 /// Floating point literal.
484 #[unstable(feature = "proc_macro", issue = "38356")]
485 pub fn f32(n: f32) -> Literal {
487 panic!("Invalid f32 literal {}", n);
489 Literal(token::Literal(token::Lit::Float(Symbol::intern(&n.to_string())),
490 Some(Symbol::intern("f32"))))
493 /// Floating point literal.
494 #[unstable(feature = "proc_macro", issue = "38356")]
495 pub fn f64(n: f64) -> Literal {
497 panic!("Invalid f64 literal {}", n);
499 Literal(token::Literal(token::Lit::Float(Symbol::intern(&n.to_string())),
500 Some(Symbol::intern("f64"))))
504 #[unstable(feature = "proc_macro", issue = "38356")]
505 pub fn string(string: &str) -> Literal {
506 let mut escaped = String::new();
507 for ch in string.chars() {
508 escaped.extend(ch.escape_debug());
510 Literal(token::Literal(token::Lit::Str_(Symbol::intern(&escaped)), None))
513 /// Character literal.
514 #[unstable(feature = "proc_macro", issue = "38356")]
515 pub fn character(ch: char) -> Literal {
516 let mut escaped = String::new();
517 escaped.extend(ch.escape_unicode());
518 Literal(token::Literal(token::Lit::Char(Symbol::intern(&escaped)), None))
521 /// Byte string literal.
522 #[unstable(feature = "proc_macro", issue = "38356")]
523 pub fn byte_string(bytes: &[u8]) -> Literal {
524 let string = bytes.iter().cloned().flat_map(ascii::escape_default)
525 .map(Into::<char>::into).collect::<String>();
526 Literal(token::Literal(token::Lit::ByteStr(Symbol::intern(&string)), None))
530 /// An iterator over `TokenTree`s.
532 #[unstable(feature = "proc_macro", issue = "38356")]
533 pub struct TokenTreeIter {
534 cursor: tokenstream::Cursor,
535 next: Option<tokenstream::TokenStream>,
538 #[unstable(feature = "proc_macro", issue = "38356")]
539 impl Iterator for TokenTreeIter {
540 type Item = TokenTree;
542 fn next(&mut self) -> Option<TokenTree> {
545 unwrap_or!(self.next.take().or_else(|| self.cursor.next_as_stream()), return None);
546 let tree = TokenTree::from_internal(next, &mut self.next);
547 if tree.span.0 == DUMMY_SP {
548 if let TokenNode::Group(Delimiter::None, stream) = tree.kind {
549 self.cursor.insert(stream.0);
559 fn from_internal(delim: token::DelimToken) -> Delimiter {
561 token::Paren => Delimiter::Parenthesis,
562 token::Brace => Delimiter::Brace,
563 token::Bracket => Delimiter::Bracket,
564 token::NoDelim => Delimiter::None,
568 fn to_internal(self) -> token::DelimToken {
570 Delimiter::Parenthesis => token::Paren,
571 Delimiter::Brace => token::Brace,
572 Delimiter::Bracket => token::Bracket,
573 Delimiter::None => token::NoDelim,
579 fn from_internal(stream: tokenstream::TokenStream, next: &mut Option<tokenstream::TokenStream>)
581 use syntax::parse::token::*;
583 let (tree, is_joint) = stream.as_tree();
584 let (mut span, token) = match tree {
585 tokenstream::TokenTree::Token(span, token) => (span, token),
586 tokenstream::TokenTree::Delimited(span, delimed) => {
587 let delimiter = Delimiter::from_internal(delimed.delim);
590 kind: TokenNode::Group(delimiter, TokenStream(delimed.tts.into())),
595 let op_kind = if is_joint { Spacing::Joint } else { Spacing::Alone };
597 ($op:expr) => { TokenNode::Op($op, op_kind) }
601 ($first:expr, $rest:expr) => { joint($first, $rest, is_joint, &mut span, next) }
604 fn joint(first: char, rest: Token, is_joint: bool, span: &mut syntax_pos::Span,
605 next: &mut Option<tokenstream::TokenStream>)
607 let (first_span, rest_span) = (*span, *span);
609 let tree = tokenstream::TokenTree::Token(rest_span, rest);
610 *next = Some(if is_joint { tree.joint() } else { tree.into() });
611 TokenNode::Op(first, Spacing::Joint)
614 let kind = match token {
617 Le => joint!('<', Eq),
618 EqEq => joint!('=', Eq),
619 Ne => joint!('!', Eq),
620 Ge => joint!('>', Eq),
622 AndAnd => joint!('&', BinOp(And)),
623 OrOr => joint!('|', BinOp(Or)),
626 BinOp(Plus) => op!('+'),
627 BinOp(Minus) => op!('-'),
628 BinOp(Star) => op!('*'),
629 BinOp(Slash) => op!('/'),
630 BinOp(Percent) => op!('%'),
631 BinOp(Caret) => op!('^'),
632 BinOp(And) => op!('&'),
633 BinOp(Or) => op!('|'),
634 BinOp(Shl) => joint!('<', Lt),
635 BinOp(Shr) => joint!('>', Gt),
636 BinOpEq(Plus) => joint!('+', Eq),
637 BinOpEq(Minus) => joint!('-', Eq),
638 BinOpEq(Star) => joint!('*', Eq),
639 BinOpEq(Slash) => joint!('/', Eq),
640 BinOpEq(Percent) => joint!('%', Eq),
641 BinOpEq(Caret) => joint!('^', Eq),
642 BinOpEq(And) => joint!('&', Eq),
643 BinOpEq(Or) => joint!('|', Eq),
644 BinOpEq(Shl) => joint!('<', Le),
645 BinOpEq(Shr) => joint!('>', Ge),
648 DotDot => joint!('.', Dot),
649 DotDotDot => joint!('.', DotDot),
650 DotDotEq => joint!('.', DotEq),
654 ModSep => joint!(':', Colon),
655 RArrow => joint!('-', Gt),
656 LArrow => joint!('<', BinOp(Minus)),
657 FatArrow => joint!('=', Gt),
660 Question => op!('?'),
661 Underscore => op!('_'),
663 Ident(ident) | Lifetime(ident) => TokenNode::Term(Term(ident.name)),
664 Literal(..) | DocComment(..) => TokenNode::Literal(self::Literal(token)),
667 __internal::with_sess(|(sess, _)| {
668 let tts = token.interpolated_to_tokenstream(sess, span);
669 TokenNode::Group(Delimiter::None, TokenStream(tts))
673 DotEq => unreachable!(),
674 OpenDelim(..) | CloseDelim(..) => unreachable!(),
675 Whitespace | Comment | Shebang(..) | Eof => unreachable!(),
678 TokenTree { span: Span(span), kind: kind }
681 fn to_internal(self) -> tokenstream::TokenStream {
682 use syntax::parse::token::*;
683 use syntax::tokenstream::{TokenTree, Delimited};
685 let (op, kind) = match self.kind {
686 TokenNode::Op(op, kind) => (op, kind),
687 TokenNode::Group(delimiter, tokens) => {
688 return TokenTree::Delimited(self.span.0, Delimited {
689 delim: delimiter.to_internal(),
690 tts: tokens.0.into(),
693 TokenNode::Term(symbol) => {
694 let ident = ast::Ident { name: symbol.0, ctxt: self.span.0.ctxt() };
696 if symbol.0.as_str().starts_with("'") { Lifetime(ident) } else { Ident(ident) };
697 return TokenTree::Token(self.span.0, token).into();
699 TokenNode::Literal(token) => return TokenTree::Token(self.span.0, token.0).into(),
702 let token = match op {
712 '%' => BinOp(Percent),
725 _ => panic!("unsupported character {}", op),
728 let tree = TokenTree::Token(self.span.0, token);
730 Spacing::Alone => tree.into(),
731 Spacing::Joint => tree.joint(),
736 /// Permanently unstable internal implementation details of this crate. This
737 /// should not be used.
739 /// These methods are used by the rest of the compiler to generate instances of
740 /// `TokenStream` to hand to macro definitions, as well as consume the output.
742 /// Note that this module is also intentionally separate from the rest of the
743 /// crate. This allows the `#[unstable]` directive below to naturally apply to
744 /// all of the contents.
745 #[unstable(feature = "proc_macro_internals", issue = "27812")]
748 pub use quote::{LiteralKind, Quoter, unquote};
753 use syntax::ext::base::ExtCtxt;
754 use syntax::ext::hygiene::Mark;
756 use syntax::parse::{self, ParseSess};
757 use syntax::parse::token::{self, Token};
758 use syntax::tokenstream;
759 use syntax_pos::{BytePos, Loc, DUMMY_SP};
761 use super::{TokenStream, LexError};
763 pub fn lookup_char_pos(pos: BytePos) -> Loc {
764 with_sess(|(sess, _)| sess.codemap().lookup_char_pos(pos))
767 pub fn new_token_stream(item: P<ast::Item>) -> TokenStream {
768 let token = Token::interpolated(token::NtItem(item));
769 TokenStream(tokenstream::TokenTree::Token(DUMMY_SP, token).into())
772 pub fn token_stream_wrap(inner: tokenstream::TokenStream) -> TokenStream {
776 pub fn token_stream_parse_items(stream: TokenStream) -> Result<Vec<P<ast::Item>>, LexError> {
777 with_sess(move |(sess, _)| {
778 let mut parser = parse::stream_to_parser(sess, stream.0);
779 let mut items = Vec::new();
781 while let Some(item) = try!(parser.parse_item().map_err(super::parse_to_lex_err)) {
789 pub fn token_stream_inner(stream: TokenStream) -> tokenstream::TokenStream {
794 fn register_custom_derive(&mut self,
796 expand: fn(TokenStream) -> TokenStream,
797 attributes: &[&'static str]);
799 fn register_attr_proc_macro(&mut self,
801 expand: fn(TokenStream, TokenStream) -> TokenStream);
803 fn register_bang_proc_macro(&mut self,
805 expand: fn(TokenStream) -> TokenStream);
808 // Emulate scoped_thread_local!() here essentially
810 static CURRENT_SESS: Cell<(*const ParseSess, Mark)> =
811 Cell::new((0 as *const _, Mark::root()));
814 pub fn set_sess<F, R>(cx: &ExtCtxt, f: F) -> R
815 where F: FnOnce() -> R
817 struct Reset { prev: (*const ParseSess, Mark) }
819 impl Drop for Reset {
821 CURRENT_SESS.with(|p| p.set(self.prev));
825 CURRENT_SESS.with(|p| {
826 let _reset = Reset { prev: p.get() };
827 p.set((cx.parse_sess, cx.current_expansion.mark));
832 pub fn with_sess<F, R>(f: F) -> R
833 where F: FnOnce((&ParseSess, Mark)) -> R
835 let p = CURRENT_SESS.with(|p| p.get());
836 assert!(!p.0.is_null(), "proc_macro::__internal::with_sess() called \
837 before set_parse_sess()!");
838 f(unsafe { (&*p.0, p.1) })
842 fn parse_to_lex_err(mut err: DiagnosticBuilder) -> LexError {
844 LexError { _inner: () }