1 // Copyright 2012-2014 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 pub use self::PathParsingMode::*;
15 use ast::{RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
16 use ast::{Public, Unsafety};
17 use ast::{Mod, BiAdd, Arg, Arm, Attribute, BindByRef, BindByValue};
18 use ast::{BiBitAnd, BiBitOr, BiBitXor, BiRem, BiLt, BiGt, Block};
19 use ast::{BlockCheckMode, CaptureByRef, CaptureByValue, CaptureClause};
20 use ast::{Constness, ConstImplItem, ConstTraitItem, Crate, CrateConfig};
21 use ast::{Decl, DeclItem, DeclLocal, DefaultBlock, DefaultReturn};
22 use ast::{UnDeref, BiDiv, EMPTY_CTXT, EnumDef, ExplicitSelf};
23 use ast::{Expr, Expr_, ExprAddrOf, ExprMatch, ExprAgain};
24 use ast::{ExprAssign, ExprAssignOp, ExprBinary, ExprBlock, ExprBox};
25 use ast::{ExprBreak, ExprCall, ExprCast};
26 use ast::{ExprField, ExprTupField, ExprClosure, ExprIf, ExprIfLet, ExprIndex};
27 use ast::{ExprLit, ExprLoop, ExprMac, ExprRange};
28 use ast::{ExprMethodCall, ExprParen, ExprPath};
29 use ast::{ExprRepeat, ExprRet, ExprStruct, ExprTup, ExprUnary};
30 use ast::{ExprVec, ExprWhile, ExprWhileLet, ExprForLoop, Field, FnDecl};
31 use ast::{ForeignItem, ForeignItemStatic, ForeignItemFn, ForeignMod, FunctionRetTy};
32 use ast::{Ident, Inherited, ImplItem, Item, Item_, ItemStatic};
33 use ast::{ItemEnum, ItemFn, ItemForeignMod, ItemImpl, ItemConst};
34 use ast::{ItemMac, ItemMod, ItemStruct, ItemTrait, ItemTy, ItemDefaultImpl};
35 use ast::{ItemExternCrate, ItemUse};
36 use ast::{LifetimeDef, Lit, Lit_};
37 use ast::{LitBool, LitChar, LitByte, LitByteStr};
38 use ast::{LitStr, LitInt, Local};
39 use ast::{MacStmtWithBraces, MacStmtWithSemicolon, MacStmtWithoutBraces};
40 use ast::{MutImmutable, MutMutable, Mac_, MacInvocTT, MatchSource};
41 use ast::{MutTy, BiMul, Mutability};
42 use ast::{MethodImplItem, NamedField, UnNeg, NoReturn, UnNot};
43 use ast::{Pat, PatBox, PatEnum, PatIdent, PatLit, PatQPath, PatMac, PatRange};
44 use ast::{PatRegion, PatStruct, PatTup, PatVec, PatWild, PatWildMulti};
45 use ast::PatWildSingle;
46 use ast::{PolyTraitRef, QSelf};
47 use ast::{Return, BiShl, BiShr, Stmt, StmtDecl};
48 use ast::{StmtExpr, StmtSemi, StmtMac, StructDef, StructField};
49 use ast::{StructVariantKind, BiSub, StrStyle};
50 use ast::{SelfExplicit, SelfRegion, SelfStatic, SelfValue};
51 use ast::{Delimited, SequenceRepetition, TokenTree, TraitItem, TraitRef};
52 use ast::{TtDelimited, TtSequence, TtToken};
53 use ast::{TupleVariantKind, Ty, Ty_, TypeBinding};
55 use ast::{TyFixedLengthVec, TyBareFn, TyTypeof, TyInfer};
56 use ast::{TyParam, TyParamBound, TyParen, TyPath, TyPolyTraitRef, TyPtr};
57 use ast::{TyRptr, TyTup, TyU32, TyVec, UnUniq};
58 use ast::{TypeImplItem, TypeTraitItem};
59 use ast::{UnnamedField, UnsafeBlock};
60 use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
61 use ast::{Visibility, WhereClause};
63 use ast_util::{self, AS_PREC, ident_to_path, operator_prec};
64 use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp, CodeMap};
66 use ext::tt::macro_parser;
68 use parse::attr::ParserAttr;
70 use parse::common::{SeqSep, seq_sep_none, seq_sep_trailing_allowed};
71 use parse::lexer::{Reader, TokenAndSpan};
72 use parse::obsolete::{ParserObsoleteMethods, ObsoleteSyntax};
73 use parse::token::{self, MatchNt, SubstNt, SpecialVarNt, InternedString};
74 use parse::token::{keywords, special_idents, SpecialMacroVar};
75 use parse::{new_sub_parser_from_file, ParseSess};
78 use owned_slice::OwnedSlice;
80 use diagnostic::FatalError;
82 use std::collections::HashSet;
83 use std::io::prelude::*;
85 use std::path::{Path, PathBuf};
90 flags Restrictions: u8 {
91 const RESTRICTION_STMT_EXPR = 1 << 0,
92 const RESTRICTION_NO_STRUCT_LITERAL = 1 << 1,
96 type ItemInfo = (Ident, Item_, Option<Vec<Attribute> >);
98 /// How to parse a path. There are four different kinds of paths, all of which
99 /// are parsed somewhat differently.
100 #[derive(Copy, Clone, PartialEq)]
101 pub enum PathParsingMode {
102 /// A path with no type parameters; e.g. `foo::bar::Baz`
104 /// A path with a lifetime and type parameters, with no double colons
105 /// before the type parameters; e.g. `foo::bar<'a>::Baz<T>`
106 LifetimeAndTypesWithoutColons,
107 /// A path with a lifetime and type parameters with double colons before
108 /// the type parameters; e.g. `foo::bar::<'a>::Baz::<T>`
109 LifetimeAndTypesWithColons,
112 /// How to parse a bound, whether to allow bound modifiers such as `?`.
113 #[derive(Copy, Clone, PartialEq)]
114 pub enum BoundParsingMode {
119 /// Possibly accept an `token::Interpolated` expression (a pre-parsed expression
120 /// dropped into the token stream, which happens while parsing the result of
121 /// macro expansion). Placement of these is not as complex as I feared it would
122 /// be. The important thing is to make sure that lookahead doesn't balk at
123 /// `token::Interpolated` tokens.
124 macro_rules! maybe_whole_expr {
127 let found = match $p.token {
128 token::Interpolated(token::NtExpr(ref e)) => {
131 token::Interpolated(token::NtPath(_)) => {
132 // FIXME: The following avoids an issue with lexical borrowck scopes,
133 // but the clone is unfortunate.
134 let pt = match $p.token {
135 token::Interpolated(token::NtPath(ref pt)) => (**pt).clone(),
139 Some($p.mk_expr(span.lo, span.hi, ExprPath(None, pt)))
141 token::Interpolated(token::NtBlock(_)) => {
142 // FIXME: The following avoids an issue with lexical borrowck scopes,
143 // but the clone is unfortunate.
144 let b = match $p.token {
145 token::Interpolated(token::NtBlock(ref b)) => (*b).clone(),
149 Some($p.mk_expr(span.lo, span.hi, ExprBlock(b)))
164 /// As maybe_whole_expr, but for things other than expressions
165 macro_rules! maybe_whole {
166 ($p:expr, $constructor:ident) => (
168 let found = match ($p).token {
169 token::Interpolated(token::$constructor(_)) => {
170 Some(try!(($p).bump_and_get()))
174 if let Some(token::Interpolated(token::$constructor(x))) = found {
175 return Ok(x.clone());
179 (no_clone $p:expr, $constructor:ident) => (
181 let found = match ($p).token {
182 token::Interpolated(token::$constructor(_)) => {
183 Some(try!(($p).bump_and_get()))
187 if let Some(token::Interpolated(token::$constructor(x))) = found {
192 (deref $p:expr, $constructor:ident) => (
194 let found = match ($p).token {
195 token::Interpolated(token::$constructor(_)) => {
196 Some(try!(($p).bump_and_get()))
200 if let Some(token::Interpolated(token::$constructor(x))) = found {
201 return Ok((*x).clone());
205 (Some deref $p:expr, $constructor:ident) => (
207 let found = match ($p).token {
208 token::Interpolated(token::$constructor(_)) => {
209 Some(try!(($p).bump_and_get()))
213 if let Some(token::Interpolated(token::$constructor(x))) = found {
214 return Ok(Some((*x).clone()));
218 (pair_empty $p:expr, $constructor:ident) => (
220 let found = match ($p).token {
221 token::Interpolated(token::$constructor(_)) => {
222 Some(try!(($p).bump_and_get()))
226 if let Some(token::Interpolated(token::$constructor(x))) = found {
227 return Ok((Vec::new(), x));
234 fn maybe_append(mut lhs: Vec<Attribute>, rhs: Option<Vec<Attribute>>)
236 if let Some(ref attrs) = rhs {
237 lhs.extend(attrs.iter().cloned())
242 /* ident is handled by common.rs */
244 pub struct Parser<'a> {
245 pub sess: &'a ParseSess,
246 /// the current token:
247 pub token: token::Token,
248 /// the span of the current token:
250 /// the span of the prior token:
252 pub cfg: CrateConfig,
253 /// the previous token or None (only stashed sometimes).
254 pub last_token: Option<Box<token::Token>>,
255 pub buffer: [TokenAndSpan; 4],
256 pub buffer_start: isize,
257 pub buffer_end: isize,
258 pub tokens_consumed: usize,
259 pub restrictions: Restrictions,
260 pub quote_depth: usize, // not (yet) related to the quasiquoter
261 pub reader: Box<Reader+'a>,
262 pub interner: Rc<token::IdentInterner>,
263 /// The set of seen errors about obsolete syntax. Used to suppress
264 /// extra detail when the same error is seen twice
265 pub obsolete_set: HashSet<ObsoleteSyntax>,
266 /// Used to determine the path to externally loaded source files
267 pub mod_path_stack: Vec<InternedString>,
268 /// Stack of spans of open delimiters. Used for error message.
269 pub open_braces: Vec<Span>,
270 /// Flag if this parser "owns" the directory that it is currently parsing
271 /// in. This will affect how nested files are looked up.
272 pub owns_directory: bool,
273 /// Name of the root module this parser originated from. If `None`, then the
274 /// name is not known. This does not change while the parser is descending
275 /// into modules, and sub-parsers have new values for this name.
276 pub root_module_name: Option<String>,
277 pub expected_tokens: Vec<TokenType>,
280 #[derive(PartialEq, Eq, Clone)]
283 Keyword(keywords::Keyword),
288 fn to_string(&self) -> String {
290 TokenType::Token(ref t) => format!("`{}`", Parser::token_to_string(t)),
291 TokenType::Operator => "an operator".to_string(),
292 TokenType::Keyword(kw) => format!("`{}`", kw.to_name()),
297 fn is_plain_ident_or_underscore(t: &token::Token) -> bool {
298 t.is_plain_ident() || *t == token::Underscore
301 /// Information about the path to a module.
302 pub struct ModulePath {
304 pub path_exists: bool,
305 pub result: Result<ModulePathSuccess, ModulePathError>,
308 pub struct ModulePathSuccess {
309 pub path: ::std::path::PathBuf,
310 pub owns_directory: bool,
313 pub struct ModulePathError {
315 pub help_msg: String,
319 impl<'a> Parser<'a> {
320 pub fn new(sess: &'a ParseSess,
321 cfg: ast::CrateConfig,
322 mut rdr: Box<Reader+'a>)
325 let tok0 = rdr.real_token();
327 let placeholder = TokenAndSpan {
328 tok: token::Underscore,
334 interner: token::get_ident_interner(),
350 restrictions: Restrictions::empty(),
352 obsolete_set: HashSet::new(),
353 mod_path_stack: Vec::new(),
354 open_braces: Vec::new(),
355 owns_directory: true,
356 root_module_name: None,
357 expected_tokens: Vec::new(),
361 // Panicing fns (for now!)
362 // This is so that the quote_*!() syntax extensions
363 pub fn parse_expr(&mut self) -> P<Expr> {
364 panictry!(self.parse_expr_nopanic())
367 pub fn parse_item(&mut self) -> Option<P<Item>> {
368 panictry!(self.parse_item_nopanic())
371 pub fn parse_pat(&mut self) -> P<Pat> {
372 panictry!(self.parse_pat_nopanic())
375 pub fn parse_arm(&mut self) -> Arm {
376 panictry!(self.parse_arm_nopanic())
379 pub fn parse_ty(&mut self) -> P<Ty> {
380 panictry!(self.parse_ty_nopanic())
383 pub fn parse_stmt(&mut self) -> Option<P<Stmt>> {
384 panictry!(self.parse_stmt_nopanic())
387 /// Convert a token to a string using self's reader
388 pub fn token_to_string(token: &token::Token) -> String {
389 pprust::token_to_string(token)
392 /// Convert the current token to a string using self's reader
393 pub fn this_token_to_string(&self) -> String {
394 Parser::token_to_string(&self.token)
397 pub fn unexpected_last(&self, t: &token::Token) -> FatalError {
398 let token_str = Parser::token_to_string(t);
399 let last_span = self.last_span;
400 self.span_fatal(last_span, &format!("unexpected token: `{}`",
404 pub fn unexpected(&mut self) -> FatalError {
405 match self.expect_one_of(&[], &[]) {
407 Ok(_) => unreachable!()
411 /// Expect and consume the token t. Signal an error if
412 /// the next token is not t.
413 pub fn expect(&mut self, t: &token::Token) -> PResult<()> {
414 if self.expected_tokens.is_empty() {
415 if self.token == *t {
418 let token_str = Parser::token_to_string(t);
419 let this_token_str = self.this_token_to_string();
420 Err(self.fatal(&format!("expected `{}`, found `{}`",
425 self.expect_one_of(slice::ref_slice(t), &[])
429 /// Expect next token to be edible or inedible token. If edible,
430 /// then consume it; if inedible, then return without consuming
431 /// anything. Signal a fatal error if next token is unexpected.
432 pub fn expect_one_of(&mut self,
433 edible: &[token::Token],
434 inedible: &[token::Token]) -> PResult<()>{
435 fn tokens_to_string(tokens: &[TokenType]) -> String {
436 let mut i = tokens.iter();
437 // This might be a sign we need a connect method on Iterator.
439 .map_or("".to_string(), |t| t.to_string());
440 i.enumerate().fold(b, |mut b, (i, ref a)| {
441 if tokens.len() > 2 && i == tokens.len() - 2 {
443 } else if tokens.len() == 2 && i == tokens.len() - 2 {
448 b.push_str(&*a.to_string());
452 if edible.contains(&self.token) {
454 } else if inedible.contains(&self.token) {
455 // leave it in the input
458 let mut expected = edible.iter()
459 .map(|x| TokenType::Token(x.clone()))
460 .chain(inedible.iter().map(|x| TokenType::Token(x.clone())))
461 .chain(self.expected_tokens.iter().cloned())
462 .collect::<Vec<_>>();
463 expected.sort_by(|a, b| a.to_string().cmp(&b.to_string()));
465 let expect = tokens_to_string(&expected[..]);
466 let actual = self.this_token_to_string();
468 &(if expected.len() > 1 {
469 (format!("expected one of {}, found `{}`",
472 } else if expected.is_empty() {
473 (format!("unexpected token: `{}`",
476 (format!("expected {}, found `{}`",
484 /// Check for erroneous `ident { }`; if matches, signal error and
485 /// recover (without consuming any expected input token). Returns
486 /// true if and only if input was consumed for recovery.
487 pub fn check_for_erroneous_unit_struct_expecting(&mut self,
488 expected: &[token::Token])
490 if self.token == token::OpenDelim(token::Brace)
491 && expected.iter().all(|t| *t != token::OpenDelim(token::Brace))
492 && self.look_ahead(1, |t| *t == token::CloseDelim(token::Brace)) {
493 // matched; signal non-fatal error and recover.
494 let span = self.span;
496 "unit-like struct construction is written with no trailing `{ }`");
497 try!(self.eat(&token::OpenDelim(token::Brace)));
498 try!(self.eat(&token::CloseDelim(token::Brace)));
505 /// Commit to parsing a complete expression `e` expected to be
506 /// followed by some token from the set edible + inedible. Recover
507 /// from anticipated input errors, discarding erroneous characters.
508 pub fn commit_expr(&mut self, e: &Expr, edible: &[token::Token],
509 inedible: &[token::Token]) -> PResult<()> {
510 debug!("commit_expr {:?}", e);
511 if let ExprPath(..) = e.node {
512 // might be unit-struct construction; check for recoverableinput error.
513 let expected = edible.iter()
515 .chain(inedible.iter().cloned())
516 .collect::<Vec<_>>();
517 try!(self.check_for_erroneous_unit_struct_expecting(&expected[..]));
519 self.expect_one_of(edible, inedible)
522 pub fn commit_expr_expecting(&mut self, e: &Expr, edible: token::Token) -> PResult<()> {
523 self.commit_expr(e, &[edible], &[])
526 /// Commit to parsing a complete statement `s`, which expects to be
527 /// followed by some token from the set edible + inedible. Check
528 /// for recoverable input errors, discarding erroneous characters.
529 pub fn commit_stmt(&mut self, edible: &[token::Token],
530 inedible: &[token::Token]) -> PResult<()> {
533 .map_or(false, |t| t.is_ident() || t.is_path()) {
534 let expected = edible.iter()
536 .chain(inedible.iter().cloned())
537 .collect::<Vec<_>>();
538 try!(self.check_for_erroneous_unit_struct_expecting(&expected));
540 self.expect_one_of(edible, inedible)
543 pub fn commit_stmt_expecting(&mut self, edible: token::Token) -> PResult<()> {
544 self.commit_stmt(&[edible], &[])
547 pub fn parse_ident(&mut self) -> PResult<ast::Ident> {
548 self.check_strict_keywords();
549 try!(self.check_reserved_keywords());
551 token::Ident(i, _) => {
555 token::Interpolated(token::NtIdent(..)) => {
556 self.bug("ident interpolation not converted to real token");
559 let token_str = self.this_token_to_string();
560 Err(self.fatal(&format!("expected ident, found `{}`",
566 pub fn parse_ident_or_self_type(&mut self) -> PResult<ast::Ident> {
567 if self.is_self_type_ident() {
568 self.expect_self_type_ident()
574 pub fn parse_path_list_item(&mut self) -> PResult<ast::PathListItem> {
575 let lo = self.span.lo;
576 let node = if try!(self.eat_keyword(keywords::SelfValue)) {
577 let rename = try!(self.parse_rename());
578 ast::PathListMod { id: ast::DUMMY_NODE_ID, rename: rename }
580 let ident = try!(self.parse_ident());
581 let rename = try!(self.parse_rename());
582 ast::PathListIdent { name: ident, rename: rename, id: ast::DUMMY_NODE_ID }
584 let hi = self.last_span.hi;
585 Ok(spanned(lo, hi, node))
588 /// Check if the next token is `tok`, and return `true` if so.
590 /// This method is will automatically add `tok` to `expected_tokens` if `tok` is not
592 pub fn check(&mut self, tok: &token::Token) -> bool {
593 let is_present = self.token == *tok;
594 if !is_present { self.expected_tokens.push(TokenType::Token(tok.clone())); }
598 /// Consume token 'tok' if it exists. Returns true if the given
599 /// token was present, false otherwise.
600 pub fn eat(&mut self, tok: &token::Token) -> PResult<bool> {
601 let is_present = self.check(tok);
602 if is_present { try!(self.bump())}
606 pub fn check_keyword(&mut self, kw: keywords::Keyword) -> bool {
607 self.expected_tokens.push(TokenType::Keyword(kw));
608 self.token.is_keyword(kw)
611 /// If the next token is the given keyword, eat it and return
612 /// true. Otherwise, return false.
613 pub fn eat_keyword(&mut self, kw: keywords::Keyword) -> PResult<bool> {
614 if self.check_keyword(kw) {
622 pub fn eat_keyword_noexpect(&mut self, kw: keywords::Keyword) -> PResult<bool> {
623 if self.token.is_keyword(kw) {
631 /// If the given word is not a keyword, signal an error.
632 /// If the next token is not the given word, signal an error.
633 /// Otherwise, eat it.
634 pub fn expect_keyword(&mut self, kw: keywords::Keyword) -> PResult<()> {
635 if !try!(self.eat_keyword(kw) ){
636 self.expect_one_of(&[], &[])
642 /// Signal an error if the given string is a strict keyword
643 pub fn check_strict_keywords(&mut self) {
644 if self.token.is_strict_keyword() {
645 let token_str = self.this_token_to_string();
646 let span = self.span;
648 &format!("expected identifier, found keyword `{}`",
653 /// Signal an error if the current token is a reserved keyword
654 pub fn check_reserved_keywords(&mut self) -> PResult<()>{
655 if self.token.is_reserved_keyword() {
656 let token_str = self.this_token_to_string();
657 Err(self.fatal(&format!("`{}` is a reserved keyword",
664 /// Expect and consume an `&`. If `&&` is seen, replace it with a single
665 /// `&` and continue. If an `&` is not seen, signal an error.
666 fn expect_and(&mut self) -> PResult<()> {
667 self.expected_tokens.push(TokenType::Token(token::BinOp(token::And)));
669 token::BinOp(token::And) => self.bump(),
671 let span = self.span;
672 let lo = span.lo + BytePos(1);
673 Ok(self.replace_token(token::BinOp(token::And), lo, span.hi))
675 _ => self.expect_one_of(&[], &[])
679 pub fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<ast::Name>) {
681 None => {/* everything ok */}
683 let text = suf.as_str();
685 self.span_bug(sp, "found empty literal suffix in Some")
687 self.span_err(sp, &*format!("{} with a suffix is invalid", kind));
693 /// Attempt to consume a `<`. If `<<` is seen, replace it with a single
694 /// `<` and continue. If a `<` is not seen, return false.
696 /// This is meant to be used when parsing generics on a path to get the
698 fn eat_lt(&mut self) -> PResult<bool> {
699 self.expected_tokens.push(TokenType::Token(token::Lt));
701 token::Lt => { try!(self.bump()); Ok(true)}
702 token::BinOp(token::Shl) => {
703 let span = self.span;
704 let lo = span.lo + BytePos(1);
705 self.replace_token(token::Lt, lo, span.hi);
712 fn expect_lt(&mut self) -> PResult<()> {
713 if !try!(self.eat_lt()) {
714 self.expect_one_of(&[], &[])
720 /// Expect and consume a GT. if a >> is seen, replace it
721 /// with a single > and continue. If a GT is not seen,
723 pub fn expect_gt(&mut self) -> PResult<()> {
724 self.expected_tokens.push(TokenType::Token(token::Gt));
726 token::Gt => self.bump(),
727 token::BinOp(token::Shr) => {
728 let span = self.span;
729 let lo = span.lo + BytePos(1);
730 Ok(self.replace_token(token::Gt, lo, span.hi))
732 token::BinOpEq(token::Shr) => {
733 let span = self.span;
734 let lo = span.lo + BytePos(1);
735 Ok(self.replace_token(token::Ge, lo, span.hi))
738 let span = self.span;
739 let lo = span.lo + BytePos(1);
740 Ok(self.replace_token(token::Eq, lo, span.hi))
743 let gt_str = Parser::token_to_string(&token::Gt);
744 let this_token_str = self.this_token_to_string();
745 Err(self.fatal(&format!("expected `{}`, found `{}`",
752 pub fn parse_seq_to_before_gt_or_return<T, F>(&mut self,
753 sep: Option<token::Token>,
755 -> PResult<(OwnedSlice<T>, bool)> where
756 F: FnMut(&mut Parser) -> PResult<Option<T>>,
758 let mut v = Vec::new();
759 // This loop works by alternating back and forth between parsing types
760 // and commas. For example, given a string `A, B,>`, the parser would
761 // first parse `A`, then a comma, then `B`, then a comma. After that it
762 // would encounter a `>` and stop. This lets the parser handle trailing
763 // commas in generic parameters, because it can stop either after
764 // parsing a type or after parsing a comma.
766 if self.check(&token::Gt)
767 || self.token == token::BinOp(token::Shr)
768 || self.token == token::Ge
769 || self.token == token::BinOpEq(token::Shr) {
774 match try!(f(self)) {
775 Some(result) => v.push(result),
776 None => return Ok((OwnedSlice::from_vec(v), true))
779 if let Some(t) = sep.as_ref() {
780 try!(self.expect(t));
785 return Ok((OwnedSlice::from_vec(v), false));
788 /// Parse a sequence bracketed by '<' and '>', stopping
790 pub fn parse_seq_to_before_gt<T, F>(&mut self,
791 sep: Option<token::Token>,
793 -> PResult<OwnedSlice<T>> where
794 F: FnMut(&mut Parser) -> PResult<T>,
796 let (result, returned) = try!(self.parse_seq_to_before_gt_or_return(sep,
797 |p| Ok(Some(try!(f(p))))));
802 pub fn parse_seq_to_gt<T, F>(&mut self,
803 sep: Option<token::Token>,
805 -> PResult<OwnedSlice<T>> where
806 F: FnMut(&mut Parser) -> PResult<T>,
808 let v = try!(self.parse_seq_to_before_gt(sep, f));
809 try!(self.expect_gt());
813 pub fn parse_seq_to_gt_or_return<T, F>(&mut self,
814 sep: Option<token::Token>,
816 -> PResult<(OwnedSlice<T>, bool)> where
817 F: FnMut(&mut Parser) -> PResult<Option<T>>,
819 let (v, returned) = try!(self.parse_seq_to_before_gt_or_return(sep, f));
821 try!(self.expect_gt());
823 return Ok((v, returned));
826 /// Parse a sequence, including the closing delimiter. The function
827 /// f must consume tokens until reaching the next separator or
829 pub fn parse_seq_to_end<T, F>(&mut self,
833 -> PResult<Vec<T>> where
834 F: FnMut(&mut Parser) -> PResult<T>,
836 let val = try!(self.parse_seq_to_before_end(ket, sep, f));
841 /// Parse a sequence, not including the closing delimiter. The function
842 /// f must consume tokens until reaching the next separator or
844 pub fn parse_seq_to_before_end<T, F>(&mut self,
848 -> PResult<Vec<T>> where
849 F: FnMut(&mut Parser) -> PResult<T>,
851 let mut first: bool = true;
853 while self.token != *ket {
856 if first { first = false; }
857 else { try!(self.expect(t)); }
861 if sep.trailing_sep_allowed && self.check(ket) { break; }
862 v.push(try!(f(self)));
867 /// Parse a sequence, including the closing delimiter. The function
868 /// f must consume tokens until reaching the next separator or
870 pub fn parse_unspanned_seq<T, F>(&mut self,
875 -> PResult<Vec<T>> where
876 F: FnMut(&mut Parser) -> PResult<T>,
878 try!(self.expect(bra));
879 let result = try!(self.parse_seq_to_before_end(ket, sep, f));
884 /// Parse a sequence parameter of enum variant. For consistency purposes,
885 /// these should not be empty.
886 pub fn parse_enum_variant_seq<T, F>(&mut self,
891 -> PResult<Vec<T>> where
892 F: FnMut(&mut Parser) -> PResult<T>,
894 let result = try!(self.parse_unspanned_seq(bra, ket, sep, f));
895 if result.is_empty() {
896 let last_span = self.last_span;
897 self.span_err(last_span,
898 "nullary enum variants are written with no trailing `( )`");
903 // NB: Do not use this function unless you actually plan to place the
904 // spanned list in the AST.
905 pub fn parse_seq<T, F>(&mut self,
910 -> PResult<Spanned<Vec<T>>> where
911 F: FnMut(&mut Parser) -> PResult<T>,
913 let lo = self.span.lo;
914 try!(self.expect(bra));
915 let result = try!(self.parse_seq_to_before_end(ket, sep, f));
916 let hi = self.span.hi;
918 Ok(spanned(lo, hi, result))
921 /// Advance the parser by one token
922 pub fn bump(&mut self) -> PResult<()> {
923 self.last_span = self.span;
924 // Stash token for error recovery (sometimes; clone is not necessarily cheap).
925 self.last_token = if self.token.is_ident() ||
926 self.token.is_path() ||
927 self.token == token::Comma {
928 Some(Box::new(self.token.clone()))
932 let next = if self.buffer_start == self.buffer_end {
933 self.reader.real_token()
935 // Avoid token copies with `replace`.
936 let buffer_start = self.buffer_start as usize;
937 let next_index = (buffer_start + 1) & 3;
938 self.buffer_start = next_index as isize;
940 let placeholder = TokenAndSpan {
941 tok: token::Underscore,
944 mem::replace(&mut self.buffer[buffer_start], placeholder)
947 self.token = next.tok;
948 self.tokens_consumed += 1;
949 self.expected_tokens.clear();
950 // check after each token
951 self.check_unknown_macro_variable()
954 /// Advance the parser by one token and return the bumped token.
955 pub fn bump_and_get(&mut self) -> PResult<token::Token> {
956 let old_token = mem::replace(&mut self.token, token::Underscore);
961 /// EFFECT: replace the current token and span with the given one
962 pub fn replace_token(&mut self,
966 self.last_span = mk_sp(self.span.lo, lo);
968 self.span = mk_sp(lo, hi);
970 pub fn buffer_length(&mut self) -> isize {
971 if self.buffer_start <= self.buffer_end {
972 return self.buffer_end - self.buffer_start;
974 return (4 - self.buffer_start) + self.buffer_end;
976 pub fn look_ahead<R, F>(&mut self, distance: usize, f: F) -> R where
977 F: FnOnce(&token::Token) -> R,
979 let dist = distance as isize;
980 while self.buffer_length() < dist {
981 self.buffer[self.buffer_end as usize] = self.reader.real_token();
982 self.buffer_end = (self.buffer_end + 1) & 3;
984 f(&self.buffer[((self.buffer_start + dist - 1) & 3) as usize].tok)
986 pub fn fatal(&self, m: &str) -> diagnostic::FatalError {
987 self.sess.span_diagnostic.span_fatal(self.span, m)
989 pub fn span_fatal(&self, sp: Span, m: &str) -> diagnostic::FatalError {
990 self.sess.span_diagnostic.span_fatal(sp, m)
992 pub fn span_fatal_help(&self, sp: Span, m: &str, help: &str) -> diagnostic::FatalError {
993 self.span_err(sp, m);
994 self.fileline_help(sp, help);
995 diagnostic::FatalError
997 pub fn span_note(&self, sp: Span, m: &str) {
998 self.sess.span_diagnostic.span_note(sp, m)
1000 pub fn span_help(&self, sp: Span, m: &str) {
1001 self.sess.span_diagnostic.span_help(sp, m)
1003 pub fn span_suggestion(&self, sp: Span, m: &str, n: String) {
1004 self.sess.span_diagnostic.span_suggestion(sp, m, n)
1006 pub fn fileline_help(&self, sp: Span, m: &str) {
1007 self.sess.span_diagnostic.fileline_help(sp, m)
1009 pub fn bug(&self, m: &str) -> ! {
1010 self.sess.span_diagnostic.span_bug(self.span, m)
1012 pub fn warn(&self, m: &str) {
1013 self.sess.span_diagnostic.span_warn(self.span, m)
1015 pub fn span_warn(&self, sp: Span, m: &str) {
1016 self.sess.span_diagnostic.span_warn(sp, m)
1018 pub fn span_err(&self, sp: Span, m: &str) {
1019 self.sess.span_diagnostic.span_err(sp, m)
1021 pub fn span_bug(&self, sp: Span, m: &str) -> ! {
1022 self.sess.span_diagnostic.span_bug(sp, m)
1024 pub fn abort_if_errors(&self) {
1025 self.sess.span_diagnostic.handler().abort_if_errors();
1028 pub fn id_to_interned_str(&mut self, id: Ident) -> InternedString {
1032 /// Is the current token one of the keywords that signals a bare function
1034 pub fn token_is_bare_fn_keyword(&mut self) -> bool {
1035 self.check_keyword(keywords::Fn) ||
1036 self.check_keyword(keywords::Unsafe) ||
1037 self.check_keyword(keywords::Extern)
1040 pub fn get_lifetime(&mut self) -> ast::Ident {
1042 token::Lifetime(ref ident) => *ident,
1043 _ => self.bug("not a lifetime"),
1047 pub fn parse_for_in_type(&mut self) -> PResult<Ty_> {
1049 Parses whatever can come after a `for` keyword in a type.
1050 The `for` has already been consumed.
1054 - for <'lt> |S| -> T
1058 - for <'lt> [unsafe] [extern "ABI"] fn (S) -> T
1059 - for <'lt> path::foo(a, b)
1064 let lo = self.span.lo;
1066 let lifetime_defs = try!(self.parse_late_bound_lifetime_defs());
1068 // examine next token to decide to do
1069 if self.token_is_bare_fn_keyword() {
1070 self.parse_ty_bare_fn(lifetime_defs)
1072 let hi = self.span.hi;
1073 let trait_ref = try!(self.parse_trait_ref());
1074 let poly_trait_ref = ast::PolyTraitRef { bound_lifetimes: lifetime_defs,
1075 trait_ref: trait_ref,
1076 span: mk_sp(lo, hi)};
1077 let other_bounds = if try!(self.eat(&token::BinOp(token::Plus)) ){
1078 try!(self.parse_ty_param_bounds(BoundParsingMode::Bare))
1083 Some(TraitTyParamBound(poly_trait_ref, TraitBoundModifier::None)).into_iter()
1084 .chain(other_bounds.into_vec())
1086 Ok(ast::TyPolyTraitRef(all_bounds))
1090 pub fn parse_ty_path(&mut self) -> PResult<Ty_> {
1091 Ok(TyPath(None, try!(self.parse_path(LifetimeAndTypesWithoutColons))))
1094 /// parse a TyBareFn type:
1095 pub fn parse_ty_bare_fn(&mut self, lifetime_defs: Vec<ast::LifetimeDef>) -> PResult<Ty_> {
1098 [unsafe] [extern "ABI"] fn <'lt> (S) -> T
1099 ^~~~^ ^~~~^ ^~~~^ ^~^ ^
1102 | | | Argument types
1108 let unsafety = try!(self.parse_unsafety());
1109 let abi = if try!(self.eat_keyword(keywords::Extern) ){
1110 try!(self.parse_opt_abi()).unwrap_or(abi::C)
1115 try!(self.expect_keyword(keywords::Fn));
1116 let (inputs, variadic) = try!(self.parse_fn_args(false, true));
1117 let ret_ty = try!(self.parse_ret_ty());
1118 let decl = P(FnDecl {
1123 Ok(TyBareFn(P(BareFnTy {
1126 lifetimes: lifetime_defs,
1131 /// Parses an obsolete closure kind (`&:`, `&mut:`, or `:`).
1132 pub fn parse_obsolete_closure_kind(&mut self) -> PResult<()> {
1133 let lo = self.span.lo;
1135 self.check(&token::BinOp(token::And)) &&
1136 self.look_ahead(1, |t| t.is_keyword(keywords::Mut)) &&
1137 self.look_ahead(2, |t| *t == token::Colon)
1143 self.token == token::BinOp(token::And) &&
1144 self.look_ahead(1, |t| *t == token::Colon)
1149 try!(self.eat(&token::Colon))
1156 let span = mk_sp(lo, self.span.hi);
1157 self.obsolete(span, ObsoleteSyntax::ClosureKind);
1161 pub fn parse_unsafety(&mut self) -> PResult<Unsafety> {
1162 if try!(self.eat_keyword(keywords::Unsafe)) {
1163 return Ok(Unsafety::Unsafe);
1165 return Ok(Unsafety::Normal);
1169 /// Parse the items in a trait declaration
1170 pub fn parse_trait_items(&mut self) -> PResult<Vec<P<TraitItem>>> {
1171 self.parse_unspanned_seq(
1172 &token::OpenDelim(token::Brace),
1173 &token::CloseDelim(token::Brace),
1175 |p| -> PResult<P<TraitItem>> {
1176 maybe_whole!(no_clone p, NtTraitItem);
1177 let mut attrs = p.parse_outer_attributes();
1180 let (name, node) = if try!(p.eat_keyword(keywords::Type)) {
1181 let TyParam {ident, bounds, default, ..} = try!(p.parse_ty_param());
1182 try!(p.expect(&token::Semi));
1183 (ident, TypeTraitItem(bounds, default))
1184 } else if p.is_const_item() {
1185 try!(p.expect_keyword(keywords::Const));
1186 let ident = try!(p.parse_ident());
1187 try!(p.expect(&token::Colon));
1188 let ty = try!(p.parse_ty_sum());
1189 let default = if p.check(&token::Eq) {
1191 let expr = try!(p.parse_expr_nopanic());
1192 try!(p.commit_expr_expecting(&expr, token::Semi));
1195 try!(p.expect(&token::Semi));
1198 (ident, ConstTraitItem(ty, default))
1200 let (constness, unsafety, abi) = try!(p.parse_fn_front_matter());
1202 let ident = try!(p.parse_ident());
1203 let mut generics = try!(p.parse_generics());
1205 let (explicit_self, d) = try!(p.parse_fn_decl_with_self(|p|{
1206 // This is somewhat dubious; We don't want to allow
1207 // argument names to be left off if there is a
1209 p.parse_arg_general(false)
1212 generics.where_clause = try!(p.parse_where_clause());
1213 let sig = ast::MethodSig {
1215 constness: constness,
1219 explicit_self: explicit_self,
1222 let body = match p.token {
1225 debug!("parse_trait_methods(): parsing required method");
1228 token::OpenDelim(token::Brace) => {
1229 debug!("parse_trait_methods(): parsing provided method");
1230 let (inner_attrs, body) =
1231 try!(p.parse_inner_attrs_and_block());
1232 attrs.extend(inner_attrs.iter().cloned());
1237 let token_str = p.this_token_to_string();
1238 return Err(p.fatal(&format!("expected `;` or `{{`, found `{}`",
1242 (ident, ast::MethodTraitItem(sig, body))
1246 id: ast::DUMMY_NODE_ID,
1250 span: mk_sp(lo, p.last_span.hi),
1255 /// Parse a possibly mutable type
1256 pub fn parse_mt(&mut self) -> PResult<MutTy> {
1257 let mutbl = try!(self.parse_mutability());
1258 let t = try!(self.parse_ty_nopanic());
1259 Ok(MutTy { ty: t, mutbl: mutbl })
1262 /// Parse optional return type [ -> TY ] in function decl
1263 pub fn parse_ret_ty(&mut self) -> PResult<FunctionRetTy> {
1264 if try!(self.eat(&token::RArrow) ){
1265 if try!(self.eat(&token::Not) ){
1266 Ok(NoReturn(self.last_span))
1268 Ok(Return(try!(self.parse_ty_nopanic())))
1271 let pos = self.span.lo;
1272 Ok(DefaultReturn(mk_sp(pos, pos)))
1276 /// Parse a type in a context where `T1+T2` is allowed.
1277 pub fn parse_ty_sum(&mut self) -> PResult<P<Ty>> {
1278 let lo = self.span.lo;
1279 let lhs = try!(self.parse_ty_nopanic());
1281 if !try!(self.eat(&token::BinOp(token::Plus)) ){
1285 let bounds = try!(self.parse_ty_param_bounds(BoundParsingMode::Bare));
1287 // In type grammar, `+` is treated like a binary operator,
1288 // and hence both L and R side are required.
1289 if bounds.is_empty() {
1290 let last_span = self.last_span;
1291 self.span_err(last_span,
1292 "at least one type parameter bound \
1293 must be specified");
1296 let sp = mk_sp(lo, self.last_span.hi);
1297 let sum = ast::TyObjectSum(lhs, bounds);
1298 Ok(P(Ty {id: ast::DUMMY_NODE_ID, node: sum, span: sp}))
1302 pub fn parse_ty_nopanic(&mut self) -> PResult<P<Ty>> {
1303 maybe_whole!(no_clone self, NtTy);
1305 let lo = self.span.lo;
1307 let t = if self.check(&token::OpenDelim(token::Paren)) {
1310 // (t) is a parenthesized ty
1311 // (t,) is the type of a tuple with only one field,
1313 let mut ts = vec![];
1314 let mut last_comma = false;
1315 while self.token != token::CloseDelim(token::Paren) {
1316 ts.push(try!(self.parse_ty_sum()));
1317 if self.check(&token::Comma) {
1326 try!(self.expect(&token::CloseDelim(token::Paren)));
1327 if ts.len() == 1 && !last_comma {
1328 TyParen(ts.into_iter().nth(0).unwrap())
1332 } else if self.check(&token::BinOp(token::Star)) {
1333 // STAR POINTER (bare pointer?)
1335 TyPtr(try!(self.parse_ptr()))
1336 } else if self.check(&token::OpenDelim(token::Bracket)) {
1338 try!(self.expect(&token::OpenDelim(token::Bracket)));
1339 let t = try!(self.parse_ty_sum());
1341 // Parse the `; e` in `[ i32; e ]`
1342 // where `e` is a const expression
1343 let t = match try!(self.maybe_parse_fixed_length_of_vec()) {
1345 Some(suffix) => TyFixedLengthVec(t, suffix)
1347 try!(self.expect(&token::CloseDelim(token::Bracket)));
1349 } else if self.check(&token::BinOp(token::And)) ||
1350 self.token == token::AndAnd {
1352 try!(self.expect_and());
1353 try!(self.parse_borrowed_pointee())
1354 } else if self.check_keyword(keywords::For) {
1355 try!(self.parse_for_in_type())
1356 } else if self.token_is_bare_fn_keyword() {
1358 try!(self.parse_ty_bare_fn(Vec::new()))
1359 } else if try!(self.eat_keyword_noexpect(keywords::Typeof)) {
1361 // In order to not be ambiguous, the type must be surrounded by parens.
1362 try!(self.expect(&token::OpenDelim(token::Paren)));
1363 let e = try!(self.parse_expr_nopanic());
1364 try!(self.expect(&token::CloseDelim(token::Paren)));
1366 } else if try!(self.eat_lt()) {
1369 try!(self.parse_qualified_path(NoTypesAllowed));
1371 TyPath(Some(qself), path)
1372 } else if self.check(&token::ModSep) ||
1373 self.token.is_ident() ||
1374 self.token.is_path() {
1375 let path = try!(self.parse_path(LifetimeAndTypesWithoutColons));
1376 if self.check(&token::Not) {
1379 let delim = try!(self.expect_open_delim());
1380 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
1382 |p| p.parse_token_tree()));
1383 let hi = self.span.hi;
1384 TyMac(spanned(lo, hi, MacInvocTT(path, tts, EMPTY_CTXT)))
1389 } else if try!(self.eat(&token::Underscore) ){
1390 // TYPE TO BE INFERRED
1393 let this_token_str = self.this_token_to_string();
1394 let msg = format!("expected type, found `{}`", this_token_str);
1395 return Err(self.fatal(&msg[..]));
1398 let sp = mk_sp(lo, self.last_span.hi);
1399 Ok(P(Ty {id: ast::DUMMY_NODE_ID, node: t, span: sp}))
1402 pub fn parse_borrowed_pointee(&mut self) -> PResult<Ty_> {
1403 // look for `&'lt` or `&'foo ` and interpret `foo` as the region name:
1404 let opt_lifetime = try!(self.parse_opt_lifetime());
1406 let mt = try!(self.parse_mt());
1407 return Ok(TyRptr(opt_lifetime, mt));
1410 pub fn parse_ptr(&mut self) -> PResult<MutTy> {
1411 let mutbl = if try!(self.eat_keyword(keywords::Mut) ){
1413 } else if try!(self.eat_keyword(keywords::Const) ){
1416 let span = self.last_span;
1418 "bare raw pointers are no longer allowed, you should \
1419 likely use `*mut T`, but otherwise `*T` is now \
1420 known as `*const T`");
1423 let t = try!(self.parse_ty_nopanic());
1424 Ok(MutTy { ty: t, mutbl: mutbl })
1427 pub fn is_named_argument(&mut self) -> bool {
1428 let offset = match self.token {
1429 token::BinOp(token::And) => 1,
1431 _ if self.token.is_keyword(keywords::Mut) => 1,
1435 debug!("parser is_named_argument offset:{}", offset);
1438 is_plain_ident_or_underscore(&self.token)
1439 && self.look_ahead(1, |t| *t == token::Colon)
1441 self.look_ahead(offset, |t| is_plain_ident_or_underscore(t))
1442 && self.look_ahead(offset + 1, |t| *t == token::Colon)
1446 /// This version of parse arg doesn't necessarily require
1447 /// identifier names.
1448 pub fn parse_arg_general(&mut self, require_name: bool) -> PResult<Arg> {
1449 let pat = if require_name || self.is_named_argument() {
1450 debug!("parse_arg_general parse_pat (require_name:{})",
1452 let pat = try!(self.parse_pat_nopanic());
1454 try!(self.expect(&token::Colon));
1457 debug!("parse_arg_general ident_to_pat");
1458 ast_util::ident_to_pat(ast::DUMMY_NODE_ID,
1460 special_idents::invalid)
1463 let t = try!(self.parse_ty_sum());
1468 id: ast::DUMMY_NODE_ID,
1472 /// Parse a single function argument
1473 pub fn parse_arg(&mut self) -> PResult<Arg> {
1474 self.parse_arg_general(true)
1477 /// Parse an argument in a lambda header e.g. |arg, arg|
1478 pub fn parse_fn_block_arg(&mut self) -> PResult<Arg> {
1479 let pat = try!(self.parse_pat_nopanic());
1480 let t = if try!(self.eat(&token::Colon) ){
1481 try!(self.parse_ty_sum())
1484 id: ast::DUMMY_NODE_ID,
1486 span: mk_sp(self.span.lo, self.span.hi),
1492 id: ast::DUMMY_NODE_ID
1496 pub fn maybe_parse_fixed_length_of_vec(&mut self) -> PResult<Option<P<ast::Expr>>> {
1497 if self.check(&token::Semi) {
1499 Ok(Some(try!(self.parse_expr_nopanic())))
1505 /// Matches token_lit = LIT_INTEGER | ...
1506 pub fn lit_from_token(&self, tok: &token::Token) -> PResult<Lit_> {
1508 token::Interpolated(token::NtExpr(ref v)) => {
1510 ExprLit(ref lit) => { Ok(lit.node.clone()) }
1511 _ => { return Err(self.unexpected_last(tok)); }
1514 token::Literal(lit, suf) => {
1515 let (suffix_illegal, out) = match lit {
1516 token::Byte(i) => (true, LitByte(parse::byte_lit(&i.as_str()).0)),
1517 token::Char(i) => (true, LitChar(parse::char_lit(&i.as_str()).0)),
1519 // there are some valid suffixes for integer and
1520 // float literals, so all the handling is done
1522 token::Integer(s) => {
1523 (false, parse::integer_lit(&s.as_str(),
1524 suf.as_ref().map(|s| s.as_str()),
1525 &self.sess.span_diagnostic,
1528 token::Float(s) => {
1529 (false, parse::float_lit(&s.as_str(),
1530 suf.as_ref().map(|s| s.as_str()),
1531 &self.sess.span_diagnostic,
1537 LitStr(token::intern_and_get_ident(&parse::str_lit(&s.as_str())),
1540 token::StrRaw(s, n) => {
1543 token::intern_and_get_ident(&parse::raw_str_lit(&s.as_str())),
1546 token::ByteStr(i) =>
1547 (true, LitByteStr(parse::byte_str_lit(&i.as_str()))),
1548 token::ByteStrRaw(i, _) =>
1550 LitByteStr(Rc::new(i.to_string().into_bytes()))),
1554 let sp = self.last_span;
1555 self.expect_no_suffix(sp, &*format!("{} literal", lit.short_name()), suf)
1560 _ => { return Err(self.unexpected_last(tok)); }
1564 /// Matches lit = true | false | token_lit
1565 pub fn parse_lit(&mut self) -> PResult<Lit> {
1566 let lo = self.span.lo;
1567 let lit = if try!(self.eat_keyword(keywords::True) ){
1569 } else if try!(self.eat_keyword(keywords::False) ){
1572 let token = try!(self.bump_and_get());
1573 let lit = try!(self.lit_from_token(&token));
1576 Ok(codemap::Spanned { node: lit, span: mk_sp(lo, self.last_span.hi) })
1579 /// matches '-' lit | lit
1580 pub fn parse_literal_maybe_minus(&mut self) -> PResult<P<Expr>> {
1581 let minus_lo = self.span.lo;
1582 let minus_present = try!(self.eat(&token::BinOp(token::Minus)));
1584 let lo = self.span.lo;
1585 let literal = P(try!(self.parse_lit()));
1586 let hi = self.span.hi;
1587 let expr = self.mk_expr(lo, hi, ExprLit(literal));
1590 let minus_hi = self.span.hi;
1591 let unary = self.mk_unary(UnNeg, expr);
1592 Ok(self.mk_expr(minus_lo, minus_hi, unary))
1598 // QUALIFIED PATH `<TYPE [as TRAIT_REF]>::IDENT[::<PARAMS>]`
1599 // Assumes that the leading `<` has been parsed already.
1600 pub fn parse_qualified_path(&mut self, mode: PathParsingMode)
1601 -> PResult<(QSelf, ast::Path)> {
1602 let span = self.last_span;
1603 let self_type = try!(self.parse_ty_sum());
1604 let mut path = if try!(self.eat_keyword(keywords::As)) {
1605 try!(self.parse_path(LifetimeAndTypesWithoutColons))
1616 position: path.segments.len()
1619 try!(self.expect(&token::Gt));
1620 try!(self.expect(&token::ModSep));
1622 let segments = match mode {
1623 LifetimeAndTypesWithoutColons => {
1624 try!(self.parse_path_segments_without_colons())
1626 LifetimeAndTypesWithColons => {
1627 try!(self.parse_path_segments_with_colons())
1630 try!(self.parse_path_segments_without_types())
1633 path.segments.extend(segments);
1635 path.span.hi = self.last_span.hi;
1640 /// Parses a path and optional type parameter bounds, depending on the
1641 /// mode. The `mode` parameter determines whether lifetimes, types, and/or
1642 /// bounds are permitted and whether `::` must precede type parameter
1644 pub fn parse_path(&mut self, mode: PathParsingMode) -> PResult<ast::Path> {
1645 // Check for a whole path...
1646 let found = match self.token {
1647 token::Interpolated(token::NtPath(_)) => Some(try!(self.bump_and_get())),
1650 if let Some(token::Interpolated(token::NtPath(path))) = found {
1654 let lo = self.span.lo;
1655 let is_global = try!(self.eat(&token::ModSep));
1657 // Parse any number of segments and bound sets. A segment is an
1658 // identifier followed by an optional lifetime and a set of types.
1659 // A bound set is a set of type parameter bounds.
1660 let segments = match mode {
1661 LifetimeAndTypesWithoutColons => {
1662 try!(self.parse_path_segments_without_colons())
1664 LifetimeAndTypesWithColons => {
1665 try!(self.parse_path_segments_with_colons())
1668 try!(self.parse_path_segments_without_types())
1672 // Assemble the span.
1673 let span = mk_sp(lo, self.last_span.hi);
1675 // Assemble the result.
1684 /// - `a::b<T,U>::c<V,W>`
1685 /// - `a::b<T,U>::c(V) -> W`
1686 /// - `a::b<T,U>::c(V)`
1687 pub fn parse_path_segments_without_colons(&mut self) -> PResult<Vec<ast::PathSegment>> {
1688 let mut segments = Vec::new();
1690 // First, parse an identifier.
1691 let identifier = try!(self.parse_ident_or_self_type());
1693 // Parse types, optionally.
1694 let parameters = if try!(self.eat_lt() ){
1695 let (lifetimes, types, bindings) = try!(self.parse_generic_values_after_lt());
1697 ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
1698 lifetimes: lifetimes,
1699 types: OwnedSlice::from_vec(types),
1700 bindings: OwnedSlice::from_vec(bindings),
1702 } else if try!(self.eat(&token::OpenDelim(token::Paren)) ){
1703 let lo = self.last_span.lo;
1705 let inputs = try!(self.parse_seq_to_end(
1706 &token::CloseDelim(token::Paren),
1707 seq_sep_trailing_allowed(token::Comma),
1708 |p| p.parse_ty_sum()));
1710 let output_ty = if try!(self.eat(&token::RArrow) ){
1711 Some(try!(self.parse_ty_nopanic()))
1716 let hi = self.last_span.hi;
1718 ast::ParenthesizedParameters(ast::ParenthesizedParameterData {
1719 span: mk_sp(lo, hi),
1724 ast::PathParameters::none()
1727 // Assemble and push the result.
1728 segments.push(ast::PathSegment { identifier: identifier,
1729 parameters: parameters });
1731 // Continue only if we see a `::`
1732 if !try!(self.eat(&token::ModSep) ){
1733 return Ok(segments);
1739 /// - `a::b::<T,U>::c`
1740 pub fn parse_path_segments_with_colons(&mut self) -> PResult<Vec<ast::PathSegment>> {
1741 let mut segments = Vec::new();
1743 // First, parse an identifier.
1744 let identifier = try!(self.parse_ident_or_self_type());
1746 // If we do not see a `::`, stop.
1747 if !try!(self.eat(&token::ModSep) ){
1748 segments.push(ast::PathSegment {
1749 identifier: identifier,
1750 parameters: ast::PathParameters::none()
1752 return Ok(segments);
1755 // Check for a type segment.
1756 if try!(self.eat_lt() ){
1757 // Consumed `a::b::<`, go look for types
1758 let (lifetimes, types, bindings) = try!(self.parse_generic_values_after_lt());
1759 segments.push(ast::PathSegment {
1760 identifier: identifier,
1761 parameters: ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
1762 lifetimes: lifetimes,
1763 types: OwnedSlice::from_vec(types),
1764 bindings: OwnedSlice::from_vec(bindings),
1768 // Consumed `a::b::<T,U>`, check for `::` before proceeding
1769 if !try!(self.eat(&token::ModSep) ){
1770 return Ok(segments);
1773 // Consumed `a::`, go look for `b`
1774 segments.push(ast::PathSegment {
1775 identifier: identifier,
1776 parameters: ast::PathParameters::none(),
1785 pub fn parse_path_segments_without_types(&mut self) -> PResult<Vec<ast::PathSegment>> {
1786 let mut segments = Vec::new();
1788 // First, parse an identifier.
1789 let identifier = try!(self.parse_ident_or_self_type());
1791 // Assemble and push the result.
1792 segments.push(ast::PathSegment {
1793 identifier: identifier,
1794 parameters: ast::PathParameters::none()
1797 // If we do not see a `::`, stop.
1798 if !try!(self.eat(&token::ModSep) ){
1799 return Ok(segments);
1804 /// parses 0 or 1 lifetime
1805 pub fn parse_opt_lifetime(&mut self) -> PResult<Option<ast::Lifetime>> {
1807 token::Lifetime(..) => {
1808 Ok(Some(try!(self.parse_lifetime())))
1816 /// Parses a single lifetime
1817 /// Matches lifetime = LIFETIME
1818 pub fn parse_lifetime(&mut self) -> PResult<ast::Lifetime> {
1820 token::Lifetime(i) => {
1821 let span = self.span;
1823 return Ok(ast::Lifetime {
1824 id: ast::DUMMY_NODE_ID,
1830 return Err(self.fatal(&format!("expected a lifetime name")));
1835 /// Parses `lifetime_defs = [ lifetime_defs { ',' lifetime_defs } ]` where `lifetime_def =
1836 /// lifetime [':' lifetimes]`
1837 pub fn parse_lifetime_defs(&mut self) -> PResult<Vec<ast::LifetimeDef>> {
1839 let mut res = Vec::new();
1842 token::Lifetime(_) => {
1843 let lifetime = try!(self.parse_lifetime());
1845 if try!(self.eat(&token::Colon) ){
1846 try!(self.parse_lifetimes(token::BinOp(token::Plus)))
1850 res.push(ast::LifetimeDef { lifetime: lifetime,
1860 token::Comma => { try!(self.bump());}
1861 token::Gt => { return Ok(res); }
1862 token::BinOp(token::Shr) => { return Ok(res); }
1864 let this_token_str = self.this_token_to_string();
1865 let msg = format!("expected `,` or `>` after lifetime \
1868 return Err(self.fatal(&msg[..]));
1874 /// matches lifetimes = ( lifetime ) | ( lifetime , lifetimes ) actually, it matches the empty
1875 /// one too, but putting that in there messes up the grammar....
1877 /// Parses zero or more comma separated lifetimes. Expects each lifetime to be followed by
1878 /// either a comma or `>`. Used when parsing type parameter lists, where we expect something
1879 /// like `<'a, 'b, T>`.
1880 pub fn parse_lifetimes(&mut self, sep: token::Token) -> PResult<Vec<ast::Lifetime>> {
1882 let mut res = Vec::new();
1885 token::Lifetime(_) => {
1886 res.push(try!(self.parse_lifetime()));
1893 if self.token != sep {
1901 /// Parse mutability declaration (mut/const/imm)
1902 pub fn parse_mutability(&mut self) -> PResult<Mutability> {
1903 if try!(self.eat_keyword(keywords::Mut) ){
1910 /// Parse ident COLON expr
1911 pub fn parse_field(&mut self) -> PResult<Field> {
1912 let lo = self.span.lo;
1913 let i = try!(self.parse_ident());
1914 let hi = self.last_span.hi;
1915 try!(self.expect(&token::Colon));
1916 let e = try!(self.parse_expr_nopanic());
1918 ident: spanned(lo, hi, i),
1919 span: mk_sp(lo, e.span.hi),
1924 pub fn mk_expr(&mut self, lo: BytePos, hi: BytePos, node: Expr_) -> P<Expr> {
1926 id: ast::DUMMY_NODE_ID,
1928 span: mk_sp(lo, hi),
1932 pub fn mk_unary(&mut self, unop: ast::UnOp, expr: P<Expr>) -> ast::Expr_ {
1933 ExprUnary(unop, expr)
1936 pub fn mk_binary(&mut self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::Expr_ {
1937 ExprBinary(binop, lhs, rhs)
1940 pub fn mk_call(&mut self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::Expr_ {
1944 fn mk_method_call(&mut self,
1945 ident: ast::SpannedIdent,
1949 ExprMethodCall(ident, tps, args)
1952 pub fn mk_index(&mut self, expr: P<Expr>, idx: P<Expr>) -> ast::Expr_ {
1953 ExprIndex(expr, idx)
1956 pub fn mk_range(&mut self,
1957 start: Option<P<Expr>>,
1958 end: Option<P<Expr>>)
1960 ExprRange(start, end)
1963 pub fn mk_field(&mut self, expr: P<Expr>, ident: ast::SpannedIdent) -> ast::Expr_ {
1964 ExprField(expr, ident)
1967 pub fn mk_tup_field(&mut self, expr: P<Expr>, idx: codemap::Spanned<usize>) -> ast::Expr_ {
1968 ExprTupField(expr, idx)
1971 pub fn mk_assign_op(&mut self, binop: ast::BinOp,
1972 lhs: P<Expr>, rhs: P<Expr>) -> ast::Expr_ {
1973 ExprAssignOp(binop, lhs, rhs)
1976 pub fn mk_mac_expr(&mut self, lo: BytePos, hi: BytePos, m: Mac_) -> P<Expr> {
1978 id: ast::DUMMY_NODE_ID,
1979 node: ExprMac(codemap::Spanned {node: m, span: mk_sp(lo, hi)}),
1980 span: mk_sp(lo, hi),
1984 pub fn mk_lit_u32(&mut self, i: u32) -> P<Expr> {
1985 let span = &self.span;
1986 let lv_lit = P(codemap::Spanned {
1987 node: LitInt(i as u64, ast::UnsignedIntLit(TyU32)),
1992 id: ast::DUMMY_NODE_ID,
1993 node: ExprLit(lv_lit),
1998 fn expect_open_delim(&mut self) -> PResult<token::DelimToken> {
1999 self.expected_tokens.push(TokenType::Token(token::Gt));
2001 token::OpenDelim(delim) => {
2005 _ => Err(self.fatal("expected open delimiter")),
2009 /// At the bottom (top?) of the precedence hierarchy,
2010 /// parse things like parenthesized exprs,
2011 /// macros, return, etc.
2012 pub fn parse_bottom_expr(&mut self) -> PResult<P<Expr>> {
2013 maybe_whole_expr!(self);
2015 let lo = self.span.lo;
2016 let mut hi = self.span.hi;
2020 // Note: when adding new syntax here, don't forget to adjust Token::can_begin_expr().
2022 token::OpenDelim(token::Paren) => {
2025 // (e) is parenthesized e
2026 // (e,) is a tuple with only one field, e
2027 let mut es = vec![];
2028 let mut trailing_comma = false;
2029 while self.token != token::CloseDelim(token::Paren) {
2030 es.push(try!(self.parse_expr_nopanic()));
2031 try!(self.commit_expr(&**es.last().unwrap(), &[],
2032 &[token::Comma, token::CloseDelim(token::Paren)]));
2033 if self.check(&token::Comma) {
2034 trailing_comma = true;
2038 trailing_comma = false;
2044 hi = self.last_span.hi;
2045 return if es.len() == 1 && !trailing_comma {
2046 Ok(self.mk_expr(lo, hi, ExprParen(es.into_iter().nth(0).unwrap())))
2048 Ok(self.mk_expr(lo, hi, ExprTup(es)))
2051 token::OpenDelim(token::Brace) => {
2052 return self.parse_block_expr(lo, DefaultBlock);
2054 token::BinOp(token::Or) | token::OrOr => {
2055 let lo = self.span.lo;
2056 return self.parse_lambda_expr(lo, CaptureByRef);
2058 token::Ident(id @ ast::Ident {
2059 name: token::SELF_KEYWORD_NAME,
2061 }, token::Plain) => {
2063 let path = ast_util::ident_to_path(mk_sp(lo, hi), id);
2064 ex = ExprPath(None, path);
2065 hi = self.last_span.hi;
2067 token::OpenDelim(token::Bracket) => {
2070 if self.check(&token::CloseDelim(token::Bracket)) {
2073 ex = ExprVec(Vec::new());
2076 let first_expr = try!(self.parse_expr_nopanic());
2077 if self.check(&token::Semi) {
2078 // Repeating array syntax: [ 0; 512 ]
2080 let count = try!(self.parse_expr_nopanic());
2081 try!(self.expect(&token::CloseDelim(token::Bracket)));
2082 ex = ExprRepeat(first_expr, count);
2083 } else if self.check(&token::Comma) {
2084 // Vector with two or more elements.
2086 let remaining_exprs = try!(self.parse_seq_to_end(
2087 &token::CloseDelim(token::Bracket),
2088 seq_sep_trailing_allowed(token::Comma),
2089 |p| Ok(try!(p.parse_expr_nopanic()))
2091 let mut exprs = vec!(first_expr);
2092 exprs.extend(remaining_exprs);
2093 ex = ExprVec(exprs);
2095 // Vector with one element.
2096 try!(self.expect(&token::CloseDelim(token::Bracket)));
2097 ex = ExprVec(vec!(first_expr));
2100 hi = self.last_span.hi;
2103 if try!(self.eat_lt()){
2105 try!(self.parse_qualified_path(LifetimeAndTypesWithColons));
2107 return Ok(self.mk_expr(lo, hi, ExprPath(Some(qself), path)));
2109 if try!(self.eat_keyword(keywords::Move) ){
2110 let lo = self.last_span.lo;
2111 return self.parse_lambda_expr(lo, CaptureByValue);
2113 if try!(self.eat_keyword(keywords::If)) {
2114 return self.parse_if_expr();
2116 if try!(self.eat_keyword(keywords::For) ){
2117 let lo = self.last_span.lo;
2118 return self.parse_for_expr(None, lo);
2120 if try!(self.eat_keyword(keywords::While) ){
2121 let lo = self.last_span.lo;
2122 return self.parse_while_expr(None, lo);
2124 if self.token.is_lifetime() {
2125 let lifetime = self.get_lifetime();
2126 let lo = self.span.lo;
2128 try!(self.expect(&token::Colon));
2129 if try!(self.eat_keyword(keywords::While) ){
2130 return self.parse_while_expr(Some(lifetime), lo)
2132 if try!(self.eat_keyword(keywords::For) ){
2133 return self.parse_for_expr(Some(lifetime), lo)
2135 if try!(self.eat_keyword(keywords::Loop) ){
2136 return self.parse_loop_expr(Some(lifetime), lo)
2138 return Err(self.fatal("expected `while`, `for`, or `loop` after a label"))
2140 if try!(self.eat_keyword(keywords::Loop) ){
2141 let lo = self.last_span.lo;
2142 return self.parse_loop_expr(None, lo);
2144 if try!(self.eat_keyword(keywords::Continue) ){
2145 let ex = if self.token.is_lifetime() {
2146 let ex = ExprAgain(Some(Spanned{
2147 node: self.get_lifetime(),
2155 let hi = self.last_span.hi;
2156 return Ok(self.mk_expr(lo, hi, ex));
2158 if try!(self.eat_keyword(keywords::Match) ){
2159 return self.parse_match_expr();
2161 if try!(self.eat_keyword(keywords::Unsafe) ){
2162 return self.parse_block_expr(
2164 UnsafeBlock(ast::UserProvided));
2166 if try!(self.eat_keyword(keywords::Return) ){
2167 if self.token.can_begin_expr() {
2168 let e = try!(self.parse_expr_nopanic());
2170 ex = ExprRet(Some(e));
2174 } else if try!(self.eat_keyword(keywords::Break) ){
2175 if self.token.is_lifetime() {
2176 ex = ExprBreak(Some(Spanned {
2177 node: self.get_lifetime(),
2182 ex = ExprBreak(None);
2184 hi = self.last_span.hi;
2185 } else if self.check(&token::ModSep) ||
2186 self.token.is_ident() &&
2187 !self.check_keyword(keywords::True) &&
2188 !self.check_keyword(keywords::False) {
2190 try!(self.parse_path(LifetimeAndTypesWithColons));
2192 // `!`, as an operator, is prefix, so we know this isn't that
2193 if self.check(&token::Not) {
2194 // MACRO INVOCATION expression
2197 let delim = try!(self.expect_open_delim());
2198 let tts = try!(self.parse_seq_to_end(
2199 &token::CloseDelim(delim),
2201 |p| p.parse_token_tree()));
2202 let hi = self.last_span.hi;
2204 return Ok(self.mk_mac_expr(lo,
2210 if self.check(&token::OpenDelim(token::Brace)) {
2211 // This is a struct literal, unless we're prohibited
2212 // from parsing struct literals here.
2213 let prohibited = self.restrictions.contains(
2214 Restrictions::RESTRICTION_NO_STRUCT_LITERAL
2217 // It's a struct literal.
2219 let mut fields = Vec::new();
2220 let mut base = None;
2222 while self.token != token::CloseDelim(token::Brace) {
2223 if try!(self.eat(&token::DotDot) ){
2224 base = Some(try!(self.parse_expr_nopanic()));
2228 fields.push(try!(self.parse_field()));
2229 try!(self.commit_expr(&*fields.last().unwrap().expr,
2231 &[token::CloseDelim(token::Brace)]));
2235 try!(self.expect(&token::CloseDelim(token::Brace)));
2236 ex = ExprStruct(pth, fields, base);
2237 return Ok(self.mk_expr(lo, hi, ex));
2242 ex = ExprPath(None, pth);
2244 // other literal expression
2245 let lit = try!(self.parse_lit());
2247 ex = ExprLit(P(lit));
2252 return Ok(self.mk_expr(lo, hi, ex));
2255 /// Parse a block or unsafe block
2256 pub fn parse_block_expr(&mut self, lo: BytePos, blk_mode: BlockCheckMode)
2257 -> PResult<P<Expr>> {
2258 try!(self.expect(&token::OpenDelim(token::Brace)));
2259 let blk = try!(self.parse_block_tail(lo, blk_mode));
2260 return Ok(self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk)));
2263 /// parse a.b or a(13) or a[4] or just a
2264 pub fn parse_dot_or_call_expr(&mut self) -> PResult<P<Expr>> {
2265 let b = try!(self.parse_bottom_expr());
2266 self.parse_dot_or_call_expr_with(b)
2269 pub fn parse_dot_or_call_expr_with(&mut self, e0: P<Expr>) -> PResult<P<Expr>> {
2275 if try!(self.eat(&token::Dot) ){
2277 token::Ident(i, _) => {
2278 let dot = self.last_span.hi;
2281 let (_, tys, bindings) = if try!(self.eat(&token::ModSep) ){
2282 try!(self.expect_lt());
2283 try!(self.parse_generic_values_after_lt())
2285 (Vec::new(), Vec::new(), Vec::new())
2288 if !bindings.is_empty() {
2289 let last_span = self.last_span;
2290 self.span_err(last_span, "type bindings are only permitted on trait paths");
2293 // expr.f() method call
2295 token::OpenDelim(token::Paren) => {
2296 let mut es = try!(self.parse_unspanned_seq(
2297 &token::OpenDelim(token::Paren),
2298 &token::CloseDelim(token::Paren),
2299 seq_sep_trailing_allowed(token::Comma),
2300 |p| Ok(try!(p.parse_expr_nopanic()))
2302 hi = self.last_span.hi;
2305 let id = spanned(dot, hi, i);
2306 let nd = self.mk_method_call(id, tys, es);
2307 e = self.mk_expr(lo, hi, nd);
2310 if !tys.is_empty() {
2311 let last_span = self.last_span;
2312 self.span_err(last_span,
2313 "field expressions may not \
2314 have type parameters");
2317 let id = spanned(dot, hi, i);
2318 let field = self.mk_field(e, id);
2319 e = self.mk_expr(lo, hi, field);
2323 token::Literal(token::Integer(n), suf) => {
2326 // A tuple index may not have a suffix
2327 self.expect_no_suffix(sp, "tuple index", suf);
2329 let dot = self.last_span.hi;
2333 let index = n.as_str().parse::<usize>().ok();
2336 let id = spanned(dot, hi, n);
2337 let field = self.mk_tup_field(e, id);
2338 e = self.mk_expr(lo, hi, field);
2341 let last_span = self.last_span;
2342 self.span_err(last_span, "invalid tuple or tuple struct index");
2346 token::Literal(token::Float(n), _suf) => {
2348 let last_span = self.last_span;
2349 let fstr = n.as_str();
2350 self.span_err(last_span,
2351 &format!("unexpected token: `{}`", n.as_str()));
2352 if fstr.chars().all(|x| "0123456789.".contains(x)) {
2353 let float = match fstr.parse::<f64>().ok() {
2357 self.fileline_help(last_span,
2358 &format!("try parenthesizing the first index; e.g., `(foo.{}){}`",
2359 float.trunc() as usize,
2360 format!(".{}", fstr.splitn(2, ".").last().unwrap())));
2362 self.abort_if_errors();
2365 _ => return Err(self.unexpected())
2369 if self.expr_is_complete(&*e) { break; }
2372 token::OpenDelim(token::Paren) => {
2373 let es = try!(self.parse_unspanned_seq(
2374 &token::OpenDelim(token::Paren),
2375 &token::CloseDelim(token::Paren),
2376 seq_sep_trailing_allowed(token::Comma),
2377 |p| Ok(try!(p.parse_expr_nopanic()))
2379 hi = self.last_span.hi;
2381 let nd = self.mk_call(e, es);
2382 e = self.mk_expr(lo, hi, nd);
2386 // Could be either an index expression or a slicing expression.
2387 token::OpenDelim(token::Bracket) => {
2389 let ix = try!(self.parse_expr_nopanic());
2391 try!(self.commit_expr_expecting(&*ix, token::CloseDelim(token::Bracket)));
2392 let index = self.mk_index(e, ix);
2393 e = self.mk_expr(lo, hi, index)
2401 // Parse unquoted tokens after a `$` in a token tree
2402 fn parse_unquoted(&mut self) -> PResult<TokenTree> {
2403 let mut sp = self.span;
2404 let (name, namep) = match self.token {
2408 if self.token == token::OpenDelim(token::Paren) {
2409 let Spanned { node: seq, span: seq_span } = try!(self.parse_seq(
2410 &token::OpenDelim(token::Paren),
2411 &token::CloseDelim(token::Paren),
2413 |p| p.parse_token_tree()
2415 let (sep, repeat) = try!(self.parse_sep_and_kleene_op());
2416 let name_num = macro_parser::count_names(&seq);
2417 return Ok(TtSequence(mk_sp(sp.lo, seq_span.hi),
2418 Rc::new(SequenceRepetition {
2422 num_captures: name_num
2424 } else if self.token.is_keyword_allow_following_colon(keywords::Crate) {
2426 return Ok(TtToken(sp, SpecialVarNt(SpecialMacroVar::CrateMacroVar)));
2428 sp = mk_sp(sp.lo, self.span.hi);
2429 let namep = match self.token { token::Ident(_, p) => p, _ => token::Plain };
2430 let name = try!(self.parse_ident());
2434 token::SubstNt(name, namep) => {
2440 // continue by trying to parse the `:ident` after `$name`
2441 if self.token == token::Colon && self.look_ahead(1, |t| t.is_ident() &&
2442 !t.is_strict_keyword() &&
2443 !t.is_reserved_keyword()) {
2445 sp = mk_sp(sp.lo, self.span.hi);
2446 let kindp = match self.token { token::Ident(_, p) => p, _ => token::Plain };
2447 let nt_kind = try!(self.parse_ident());
2448 Ok(TtToken(sp, MatchNt(name, nt_kind, namep, kindp)))
2450 Ok(TtToken(sp, SubstNt(name, namep)))
2454 pub fn check_unknown_macro_variable(&mut self) -> PResult<()> {
2455 if self.quote_depth == 0 {
2457 token::SubstNt(name, _) =>
2458 return Err(self.fatal(&format!("unknown macro variable `{}`",
2466 /// Parse an optional separator followed by a Kleene-style
2467 /// repetition token (+ or *).
2468 pub fn parse_sep_and_kleene_op(&mut self) -> PResult<(Option<token::Token>, ast::KleeneOp)> {
2469 fn parse_kleene_op(parser: &mut Parser) -> PResult<Option<ast::KleeneOp>> {
2470 match parser.token {
2471 token::BinOp(token::Star) => {
2472 try!(parser.bump());
2473 Ok(Some(ast::ZeroOrMore))
2475 token::BinOp(token::Plus) => {
2476 try!(parser.bump());
2477 Ok(Some(ast::OneOrMore))
2483 match try!(parse_kleene_op(self)) {
2484 Some(kleene_op) => return Ok((None, kleene_op)),
2488 let separator = try!(self.bump_and_get());
2489 match try!(parse_kleene_op(self)) {
2490 Some(zerok) => Ok((Some(separator), zerok)),
2491 None => return Err(self.fatal("expected `*` or `+`"))
2495 /// parse a single token tree from the input.
2496 pub fn parse_token_tree(&mut self) -> PResult<TokenTree> {
2497 // FIXME #6994: currently, this is too eager. It
2498 // parses token trees but also identifies TtSequence's
2499 // and token::SubstNt's; it's too early to know yet
2500 // whether something will be a nonterminal or a seq
2502 maybe_whole!(deref self, NtTT);
2504 // this is the fall-through for the 'match' below.
2505 // invariants: the current token is not a left-delimiter,
2506 // not an EOF, and not the desired right-delimiter (if
2507 // it were, parse_seq_to_before_end would have prevented
2508 // reaching this point.
2509 fn parse_non_delim_tt_tok(p: &mut Parser) -> PResult<TokenTree> {
2510 maybe_whole!(deref p, NtTT);
2512 token::CloseDelim(_) => {
2513 // This is a conservative error: only report the last unclosed delimiter. The
2514 // previous unclosed delimiters could actually be closed! The parser just hasn't
2515 // gotten to them yet.
2516 match p.open_braces.last() {
2518 Some(&sp) => p.span_note(sp, "unclosed delimiter"),
2520 let token_str = p.this_token_to_string();
2521 Err(p.fatal(&format!("incorrect close delimiter: `{}`",
2524 /* we ought to allow different depths of unquotation */
2525 token::Dollar | token::SubstNt(..) if p.quote_depth > 0 => {
2529 Ok(TtToken(p.span, try!(p.bump_and_get())))
2536 let open_braces = self.open_braces.clone();
2537 for sp in &open_braces {
2538 self.span_help(*sp, "did you mean to close this delimiter?");
2540 // There shouldn't really be a span, but it's easier for the test runner
2541 // if we give it one
2542 return Err(self.fatal("this file contains an un-closed delimiter "));
2544 token::OpenDelim(delim) => {
2545 // The span for beginning of the delimited section
2546 let pre_span = self.span;
2548 // Parse the open delimiter.
2549 self.open_braces.push(self.span);
2550 let open_span = self.span;
2553 // Parse the token trees within the delimiters
2554 let tts = try!(self.parse_seq_to_before_end(
2555 &token::CloseDelim(delim),
2557 |p| p.parse_token_tree()
2560 // Parse the close delimiter.
2561 let close_span = self.span;
2563 self.open_braces.pop().unwrap();
2565 // Expand to cover the entire delimited token tree
2566 let span = Span { hi: close_span.hi, ..pre_span };
2568 Ok(TtDelimited(span, Rc::new(Delimited {
2570 open_span: open_span,
2572 close_span: close_span,
2575 _ => parse_non_delim_tt_tok(self),
2579 // parse a stream of tokens into a list of TokenTree's,
2581 pub fn parse_all_token_trees(&mut self) -> PResult<Vec<TokenTree>> {
2582 let mut tts = Vec::new();
2583 while self.token != token::Eof {
2584 tts.push(try!(self.parse_token_tree()));
2589 /// Parse a prefix-operator expr
2590 pub fn parse_prefix_expr(&mut self) -> PResult<P<Expr>> {
2591 let lo = self.span.lo;
2594 // Note: when adding new unary operators, don't forget to adjust Token::can_begin_expr()
2599 let e = try!(self.parse_prefix_expr());
2601 ex = self.mk_unary(UnNot, e);
2603 token::BinOp(token::Minus) => {
2605 let e = try!(self.parse_prefix_expr());
2607 ex = self.mk_unary(UnNeg, e);
2609 token::BinOp(token::Star) => {
2611 let e = try!(self.parse_prefix_expr());
2613 ex = self.mk_unary(UnDeref, e);
2615 token::BinOp(token::And) | token::AndAnd => {
2616 try!(self.expect_and());
2617 let m = try!(self.parse_mutability());
2618 let e = try!(self.parse_prefix_expr());
2620 ex = ExprAddrOf(m, e);
2622 token::Ident(_, _) => {
2623 if !self.check_keyword(keywords::Box) && !self.check_keyword(keywords::In) {
2624 return self.parse_dot_or_call_expr();
2627 let lo = self.span.lo;
2628 let keyword_hi = self.span.hi;
2630 let is_in = self.token.is_keyword(keywords::In);
2634 let place = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL));
2635 let blk = try!(self.parse_block());
2637 let blk_expr = self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk));
2638 ex = ExprBox(Some(place), blk_expr);
2639 return Ok(self.mk_expr(lo, hi, ex));
2642 // FIXME (#22181) Remove `box (PLACE) EXPR` support
2643 // entirely after next release (enabling `(box (EXPR))`),
2644 // since it will be replaced by `in PLACE { EXPR }`, ...
2646 // ... but for now: check for a place: `box(PLACE) EXPR`.
2648 if try!(self.eat(&token::OpenDelim(token::Paren))) {
2649 let box_span = mk_sp(lo, self.last_span.hi);
2650 self.span_warn(box_span,
2651 "deprecated syntax; use the `in` keyword now \
2652 (e.g. change `box (<expr>) <expr>` to \
2653 `in <expr> { <expr> }`)");
2655 // Continue supporting `box () EXPR` (temporarily)
2656 if !try!(self.eat(&token::CloseDelim(token::Paren))) {
2657 let place = try!(self.parse_expr_nopanic());
2658 try!(self.expect(&token::CloseDelim(token::Paren)));
2659 // Give a suggestion to use `box()` when a parenthesised expression is used
2660 if !self.token.can_begin_expr() {
2661 let span = self.span;
2662 let this_token_to_string = self.this_token_to_string();
2664 &format!("expected expression, found `{}`",
2665 this_token_to_string));
2667 // Spanning just keyword avoids constructing
2668 // printout of arg expression (which starts
2669 // with parenthesis, as established above).
2671 let box_span = mk_sp(lo, keyword_hi);
2672 self.span_suggestion(box_span,
2673 "try using `box ()` instead:",
2675 self.abort_if_errors();
2677 let subexpression = try!(self.parse_prefix_expr());
2678 hi = subexpression.span.hi;
2679 ex = ExprBox(Some(place), subexpression);
2680 return Ok(self.mk_expr(lo, hi, ex));
2684 // Otherwise, we use the unique pointer default.
2685 let subexpression = try!(self.parse_prefix_expr());
2686 hi = subexpression.span.hi;
2688 // FIXME (pnkfelix): After working out kinks with box
2689 // desugaring, should be `ExprBox(None, subexpression)`
2691 ex = self.mk_unary(UnUniq, subexpression);
2693 _ => return self.parse_dot_or_call_expr()
2695 return Ok(self.mk_expr(lo, hi, ex));
2698 /// Parse an expression of binops
2699 pub fn parse_binops(&mut self) -> PResult<P<Expr>> {
2700 let prefix_expr = try!(self.parse_prefix_expr());
2701 self.parse_more_binops(prefix_expr, 0)
2704 /// Parse an expression of binops of at least min_prec precedence
2705 pub fn parse_more_binops(&mut self, lhs: P<Expr>, min_prec: usize) -> PResult<P<Expr>> {
2706 if self.expr_is_complete(&*lhs) { return Ok(lhs); }
2708 self.expected_tokens.push(TokenType::Operator);
2710 let cur_op_span = self.span;
2711 let cur_opt = self.token.to_binop();
2714 if ast_util::is_comparison_binop(cur_op) {
2715 self.check_no_chained_comparison(&*lhs, cur_op)
2717 let cur_prec = operator_prec(cur_op);
2718 if cur_prec >= min_prec {
2720 let expr = try!(self.parse_prefix_expr());
2721 let rhs = try!(self.parse_more_binops(expr, cur_prec + 1));
2722 let lhs_span = lhs.span;
2723 let rhs_span = rhs.span;
2724 let binary = self.mk_binary(codemap::respan(cur_op_span, cur_op), lhs, rhs);
2725 let bin = self.mk_expr(lhs_span.lo, rhs_span.hi, binary);
2726 self.parse_more_binops(bin, min_prec)
2732 if AS_PREC >= min_prec && try!(self.eat_keyword_noexpect(keywords::As) ){
2733 let rhs = try!(self.parse_ty_nopanic());
2734 let _as = self.mk_expr(lhs.span.lo,
2736 ExprCast(lhs, rhs));
2737 self.parse_more_binops(_as, min_prec)
2745 /// Produce an error if comparison operators are chained (RFC #558).
2746 /// We only need to check lhs, not rhs, because all comparison ops
2747 /// have same precedence and are left-associative
2748 fn check_no_chained_comparison(&mut self, lhs: &Expr, outer_op: ast::BinOp_) {
2749 debug_assert!(ast_util::is_comparison_binop(outer_op));
2751 ExprBinary(op, _, _) if ast_util::is_comparison_binop(op.node) => {
2752 // respan to include both operators
2753 let op_span = mk_sp(op.span.lo, self.span.hi);
2754 self.span_err(op_span,
2755 "chained comparison operators require parentheses");
2756 if op.node == BiLt && outer_op == BiGt {
2757 self.fileline_help(op_span,
2758 "use `::<...>` instead of `<...>` if you meant to specify type arguments");
2765 /// Parse an assignment expression....
2766 /// actually, this seems to be the main entry point for
2767 /// parsing an arbitrary expression.
2768 pub fn parse_assign_expr(&mut self) -> PResult<P<Expr>> {
2771 // prefix-form of range notation '..expr'
2772 // This has the same precedence as assignment expressions
2773 // (much lower than other prefix expressions) to be consistent
2774 // with the postfix-form 'expr..'
2775 let lo = self.span.lo;
2776 let mut hi = self.span.hi;
2778 let opt_end = if self.is_at_start_of_range_notation_rhs() {
2779 let end = try!(self.parse_binops());
2785 let ex = self.mk_range(None, opt_end);
2786 Ok(self.mk_expr(lo, hi, ex))
2789 let lhs = try!(self.parse_binops());
2790 self.parse_assign_expr_with(lhs)
2795 pub fn parse_assign_expr_with(&mut self, lhs: P<Expr>) -> PResult<P<Expr>> {
2796 let restrictions = self.restrictions & Restrictions::RESTRICTION_NO_STRUCT_LITERAL;
2797 let op_span = self.span;
2801 let rhs = try!(self.parse_expr_res(restrictions));
2802 Ok(self.mk_expr(lhs.span.lo, rhs.span.hi, ExprAssign(lhs, rhs)))
2804 token::BinOpEq(op) => {
2806 let rhs = try!(self.parse_expr_res(restrictions));
2807 let aop = match op {
2808 token::Plus => BiAdd,
2809 token::Minus => BiSub,
2810 token::Star => BiMul,
2811 token::Slash => BiDiv,
2812 token::Percent => BiRem,
2813 token::Caret => BiBitXor,
2814 token::And => BiBitAnd,
2815 token::Or => BiBitOr,
2816 token::Shl => BiShl,
2819 let rhs_span = rhs.span;
2820 let span = lhs.span;
2821 let assign_op = self.mk_assign_op(codemap::respan(op_span, aop), lhs, rhs);
2822 Ok(self.mk_expr(span.lo, rhs_span.hi, assign_op))
2824 // A range expression, either `expr..expr` or `expr..`.
2826 let lo = lhs.span.lo;
2827 let mut hi = self.span.hi;
2830 let opt_end = if self.is_at_start_of_range_notation_rhs() {
2831 let end = try!(self.parse_binops());
2837 let range = self.mk_range(Some(lhs), opt_end);
2838 return Ok(self.mk_expr(lo, hi, range));
2847 fn is_at_start_of_range_notation_rhs(&self) -> bool {
2848 if self.token.can_begin_expr() {
2849 // parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
2850 if self.token == token::OpenDelim(token::Brace) {
2851 return !self.restrictions.contains(Restrictions::RESTRICTION_NO_STRUCT_LITERAL);
2859 /// Parse an 'if' or 'if let' expression ('if' token already eaten)
2860 pub fn parse_if_expr(&mut self) -> PResult<P<Expr>> {
2861 if self.check_keyword(keywords::Let) {
2862 return self.parse_if_let_expr();
2864 let lo = self.last_span.lo;
2865 let cond = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL));
2866 let thn = try!(self.parse_block());
2867 let mut els: Option<P<Expr>> = None;
2868 let mut hi = thn.span.hi;
2869 if try!(self.eat_keyword(keywords::Else) ){
2870 let elexpr = try!(self.parse_else_expr());
2871 hi = elexpr.span.hi;
2874 Ok(self.mk_expr(lo, hi, ExprIf(cond, thn, els)))
2877 /// Parse an 'if let' expression ('if' token already eaten)
2878 pub fn parse_if_let_expr(&mut self) -> PResult<P<Expr>> {
2879 let lo = self.last_span.lo;
2880 try!(self.expect_keyword(keywords::Let));
2881 let pat = try!(self.parse_pat_nopanic());
2882 try!(self.expect(&token::Eq));
2883 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL));
2884 let thn = try!(self.parse_block());
2885 let (hi, els) = if try!(self.eat_keyword(keywords::Else) ){
2886 let expr = try!(self.parse_else_expr());
2887 (expr.span.hi, Some(expr))
2891 Ok(self.mk_expr(lo, hi, ExprIfLet(pat, expr, thn, els)))
2895 pub fn parse_lambda_expr(&mut self, lo: BytePos, capture_clause: CaptureClause)
2898 let decl = try!(self.parse_fn_block_decl());
2899 let body = match decl.output {
2900 DefaultReturn(_) => {
2901 // If no explicit return type is given, parse any
2902 // expr and wrap it up in a dummy block:
2903 let body_expr = try!(self.parse_expr_nopanic());
2905 id: ast::DUMMY_NODE_ID,
2907 span: body_expr.span,
2908 expr: Some(body_expr),
2909 rules: DefaultBlock,
2913 // If an explicit return type is given, require a
2914 // block to appear (RFC 968).
2915 try!(self.parse_block())
2922 ExprClosure(capture_clause, decl, body)))
2925 pub fn parse_else_expr(&mut self) -> PResult<P<Expr>> {
2926 if try!(self.eat_keyword(keywords::If) ){
2927 return self.parse_if_expr();
2929 let blk = try!(self.parse_block());
2930 return Ok(self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk)));
2934 /// Parse a 'for' .. 'in' expression ('for' token already eaten)
2935 pub fn parse_for_expr(&mut self, opt_ident: Option<ast::Ident>,
2936 span_lo: BytePos) -> PResult<P<Expr>> {
2937 // Parse: `for <src_pat> in <src_expr> <src_loop_block>`
2939 let pat = try!(self.parse_pat_nopanic());
2940 try!(self.expect_keyword(keywords::In));
2941 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL));
2942 let loop_block = try!(self.parse_block());
2943 let hi = self.last_span.hi;
2945 Ok(self.mk_expr(span_lo, hi, ExprForLoop(pat, expr, loop_block, opt_ident)))
2948 /// Parse a 'while' or 'while let' expression ('while' token already eaten)
2949 pub fn parse_while_expr(&mut self, opt_ident: Option<ast::Ident>,
2950 span_lo: BytePos) -> PResult<P<Expr>> {
2951 if self.token.is_keyword(keywords::Let) {
2952 return self.parse_while_let_expr(opt_ident, span_lo);
2954 let cond = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL));
2955 let body = try!(self.parse_block());
2956 let hi = body.span.hi;
2957 return Ok(self.mk_expr(span_lo, hi, ExprWhile(cond, body, opt_ident)));
2960 /// Parse a 'while let' expression ('while' token already eaten)
2961 pub fn parse_while_let_expr(&mut self, opt_ident: Option<ast::Ident>,
2962 span_lo: BytePos) -> PResult<P<Expr>> {
2963 try!(self.expect_keyword(keywords::Let));
2964 let pat = try!(self.parse_pat_nopanic());
2965 try!(self.expect(&token::Eq));
2966 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL));
2967 let body = try!(self.parse_block());
2968 let hi = body.span.hi;
2969 return Ok(self.mk_expr(span_lo, hi, ExprWhileLet(pat, expr, body, opt_ident)));
2972 pub fn parse_loop_expr(&mut self, opt_ident: Option<ast::Ident>,
2973 span_lo: BytePos) -> PResult<P<Expr>> {
2974 let body = try!(self.parse_block());
2975 let hi = body.span.hi;
2976 Ok(self.mk_expr(span_lo, hi, ExprLoop(body, opt_ident)))
2979 fn parse_match_expr(&mut self) -> PResult<P<Expr>> {
2980 let lo = self.last_span.lo;
2981 let discriminant = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL));
2982 try!(self.commit_expr_expecting(&*discriminant, token::OpenDelim(token::Brace)));
2983 let mut arms: Vec<Arm> = Vec::new();
2984 while self.token != token::CloseDelim(token::Brace) {
2985 arms.push(try!(self.parse_arm_nopanic()));
2987 let hi = self.span.hi;
2989 return Ok(self.mk_expr(lo, hi, ExprMatch(discriminant, arms, MatchSource::Normal)));
2992 pub fn parse_arm_nopanic(&mut self) -> PResult<Arm> {
2993 maybe_whole!(no_clone self, NtArm);
2995 let attrs = self.parse_outer_attributes();
2996 let pats = try!(self.parse_pats());
2997 let mut guard = None;
2998 if try!(self.eat_keyword(keywords::If) ){
2999 guard = Some(try!(self.parse_expr_nopanic()));
3001 try!(self.expect(&token::FatArrow));
3002 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_STMT_EXPR));
3005 !classify::expr_is_simple_block(&*expr)
3006 && self.token != token::CloseDelim(token::Brace);
3009 try!(self.commit_expr(&*expr, &[token::Comma], &[token::CloseDelim(token::Brace)]));
3011 try!(self.eat(&token::Comma));
3022 /// Parse an expression
3023 pub fn parse_expr_nopanic(&mut self) -> PResult<P<Expr>> {
3024 self.parse_expr_res(Restrictions::empty())
3027 /// Parse an expression, subject to the given restrictions
3028 pub fn parse_expr_res(&mut self, r: Restrictions) -> PResult<P<Expr>> {
3029 let old = self.restrictions;
3030 self.restrictions = r;
3031 let e = try!(self.parse_assign_expr());
3032 self.restrictions = old;
3036 /// Parse the RHS of a local variable declaration (e.g. '= 14;')
3037 fn parse_initializer(&mut self) -> PResult<Option<P<Expr>>> {
3038 if self.check(&token::Eq) {
3040 Ok(Some(try!(self.parse_expr_nopanic())))
3046 /// Parse patterns, separated by '|' s
3047 fn parse_pats(&mut self) -> PResult<Vec<P<Pat>>> {
3048 let mut pats = Vec::new();
3050 pats.push(try!(self.parse_pat_nopanic()));
3051 if self.check(&token::BinOp(token::Or)) { try!(self.bump());}
3052 else { return Ok(pats); }
3056 fn parse_pat_tuple_elements(&mut self) -> PResult<Vec<P<Pat>>> {
3057 let mut fields = vec![];
3058 if !self.check(&token::CloseDelim(token::Paren)) {
3059 fields.push(try!(self.parse_pat_nopanic()));
3060 if self.look_ahead(1, |t| *t != token::CloseDelim(token::Paren)) {
3061 while try!(self.eat(&token::Comma)) &&
3062 !self.check(&token::CloseDelim(token::Paren)) {
3063 fields.push(try!(self.parse_pat_nopanic()));
3066 if fields.len() == 1 {
3067 try!(self.expect(&token::Comma));
3073 fn parse_pat_vec_elements(
3075 ) -> PResult<(Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>)> {
3076 let mut before = Vec::new();
3077 let mut slice = None;
3078 let mut after = Vec::new();
3079 let mut first = true;
3080 let mut before_slice = true;
3082 while self.token != token::CloseDelim(token::Bracket) {
3086 try!(self.expect(&token::Comma));
3088 if self.token == token::CloseDelim(token::Bracket)
3089 && (before_slice || !after.is_empty()) {
3095 if self.check(&token::DotDot) {
3098 if self.check(&token::Comma) ||
3099 self.check(&token::CloseDelim(token::Bracket)) {
3100 slice = Some(P(ast::Pat {
3101 id: ast::DUMMY_NODE_ID,
3102 node: PatWild(PatWildMulti),
3105 before_slice = false;
3111 let subpat = try!(self.parse_pat_nopanic());
3112 if before_slice && self.check(&token::DotDot) {
3114 slice = Some(subpat);
3115 before_slice = false;
3116 } else if before_slice {
3117 before.push(subpat);
3123 Ok((before, slice, after))
3126 /// Parse the fields of a struct-like pattern
3127 fn parse_pat_fields(&mut self) -> PResult<(Vec<codemap::Spanned<ast::FieldPat>> , bool)> {
3128 let mut fields = Vec::new();
3129 let mut etc = false;
3130 let mut first = true;
3131 while self.token != token::CloseDelim(token::Brace) {
3135 try!(self.expect(&token::Comma));
3136 // accept trailing commas
3137 if self.check(&token::CloseDelim(token::Brace)) { break }
3140 let lo = self.span.lo;
3143 if self.check(&token::DotDot) {
3145 if self.token != token::CloseDelim(token::Brace) {
3146 let token_str = self.this_token_to_string();
3147 return Err(self.fatal(&format!("expected `{}`, found `{}`", "}",
3154 // Check if a colon exists one ahead. This means we're parsing a fieldname.
3155 let (subpat, fieldname, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
3156 // Parsing a pattern of the form "fieldname: pat"
3157 let fieldname = try!(self.parse_ident());
3159 let pat = try!(self.parse_pat_nopanic());
3161 (pat, fieldname, false)
3163 // Parsing a pattern of the form "(box) (ref) (mut) fieldname"
3164 let is_box = try!(self.eat_keyword(keywords::Box));
3165 let boxed_span_lo = self.span.lo;
3166 let is_ref = try!(self.eat_keyword(keywords::Ref));
3167 let is_mut = try!(self.eat_keyword(keywords::Mut));
3168 let fieldname = try!(self.parse_ident());
3169 hi = self.last_span.hi;
3171 let bind_type = match (is_ref, is_mut) {
3172 (true, true) => BindByRef(MutMutable),
3173 (true, false) => BindByRef(MutImmutable),
3174 (false, true) => BindByValue(MutMutable),
3175 (false, false) => BindByValue(MutImmutable),
3177 let fieldpath = codemap::Spanned{span:self.last_span, node:fieldname};
3178 let fieldpat = P(ast::Pat{
3179 id: ast::DUMMY_NODE_ID,
3180 node: PatIdent(bind_type, fieldpath, None),
3181 span: mk_sp(boxed_span_lo, hi),
3184 let subpat = if is_box {
3186 id: ast::DUMMY_NODE_ID,
3187 node: PatBox(fieldpat),
3188 span: mk_sp(lo, hi),
3193 (subpat, fieldname, true)
3196 fields.push(codemap::Spanned { span: mk_sp(lo, hi),
3197 node: ast::FieldPat { ident: fieldname,
3199 is_shorthand: is_shorthand }});
3201 return Ok((fields, etc));
3204 fn parse_pat_range_end(&mut self) -> PResult<P<Expr>> {
3205 if self.is_path_start() {
3206 let lo = self.span.lo;
3207 let (qself, path) = if try!(self.eat_lt()) {
3208 // Parse a qualified path
3210 try!(self.parse_qualified_path(NoTypesAllowed));
3213 // Parse an unqualified path
3214 (None, try!(self.parse_path(LifetimeAndTypesWithColons)))
3216 let hi = self.last_span.hi;
3217 Ok(self.mk_expr(lo, hi, ExprPath(qself, path)))
3219 self.parse_literal_maybe_minus()
3223 fn is_path_start(&self) -> bool {
3224 (self.token == token::Lt || self.token == token::ModSep
3225 || self.token.is_ident() || self.token.is_path())
3226 && !self.token.is_keyword(keywords::True) && !self.token.is_keyword(keywords::False)
3229 /// Parse a pattern.
3230 pub fn parse_pat_nopanic(&mut self) -> PResult<P<Pat>> {
3231 maybe_whole!(self, NtPat);
3233 let lo = self.span.lo;
3236 token::Underscore => {
3239 pat = PatWild(PatWildSingle);
3241 token::BinOp(token::And) | token::AndAnd => {
3242 // Parse &pat / &mut pat
3243 try!(self.expect_and());
3244 let mutbl = try!(self.parse_mutability());
3245 let subpat = try!(self.parse_pat_nopanic());
3246 pat = PatRegion(subpat, mutbl);
3248 token::OpenDelim(token::Paren) => {
3249 // Parse (pat,pat,pat,...) as tuple pattern
3251 let fields = try!(self.parse_pat_tuple_elements());
3252 try!(self.expect(&token::CloseDelim(token::Paren)));
3253 pat = PatTup(fields);
3255 token::OpenDelim(token::Bracket) => {
3256 // Parse [pat,pat,...] as slice pattern
3258 let (before, slice, after) = try!(self.parse_pat_vec_elements());
3259 try!(self.expect(&token::CloseDelim(token::Bracket)));
3260 pat = PatVec(before, slice, after);
3263 // At this point, token != _, &, &&, (, [
3264 if try!(self.eat_keyword(keywords::Mut)) {
3265 // Parse mut ident @ pat
3266 pat = try!(self.parse_pat_ident(BindByValue(MutMutable)));
3267 } else if try!(self.eat_keyword(keywords::Ref)) {
3268 // Parse ref ident @ pat / ref mut ident @ pat
3269 let mutbl = try!(self.parse_mutability());
3270 pat = try!(self.parse_pat_ident(BindByRef(mutbl)));
3271 } else if try!(self.eat_keyword(keywords::Box)) {
3273 let subpat = try!(self.parse_pat_nopanic());
3274 pat = PatBox(subpat);
3275 } else if self.is_path_start() {
3276 // Parse pattern starting with a path
3277 if self.token.is_plain_ident() && self.look_ahead(1, |t| *t != token::DotDotDot &&
3278 *t != token::OpenDelim(token::Brace) &&
3279 *t != token::OpenDelim(token::Paren) &&
3280 // Contrary to its definition, a plain ident can be followed by :: in macros
3281 *t != token::ModSep) {
3282 // Plain idents have some extra abilities here compared to general paths
3283 if self.look_ahead(1, |t| *t == token::Not) {
3284 // Parse macro invocation
3285 let ident = try!(self.parse_ident());
3286 let ident_span = self.last_span;
3287 let path = ident_to_path(ident_span, ident);
3289 let delim = try!(self.expect_open_delim());
3290 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
3291 seq_sep_none(), |p| p.parse_token_tree()));
3292 let mac = MacInvocTT(path, tts, EMPTY_CTXT);
3293 pat = PatMac(codemap::Spanned {node: mac, span: self.span});
3295 // Parse ident @ pat
3296 // This can give false positives and parse nullary enums,
3297 // they are dealt with later in resolve
3298 pat = try!(self.parse_pat_ident(BindByValue(MutImmutable)));
3301 let (qself, path) = if try!(self.eat_lt()) {
3302 // Parse a qualified path
3304 try!(self.parse_qualified_path(NoTypesAllowed));
3307 // Parse an unqualified path
3308 (None, try!(self.parse_path(LifetimeAndTypesWithColons)))
3311 token::DotDotDot => {
3313 let hi = self.last_span.hi;
3314 let begin = self.mk_expr(lo, hi, ExprPath(qself, path));
3316 let end = try!(self.parse_pat_range_end());
3317 pat = PatRange(begin, end);
3319 token::OpenDelim(token::Brace) => {
3320 if qself.is_some() {
3321 let span = self.span;
3323 "unexpected `{` after qualified path");
3324 self.abort_if_errors();
3326 // Parse struct pattern
3328 let (fields, etc) = try!(self.parse_pat_fields());
3330 pat = PatStruct(path, fields, etc);
3332 token::OpenDelim(token::Paren) => {
3333 if qself.is_some() {
3334 let span = self.span;
3336 "unexpected `(` after qualified path");
3337 self.abort_if_errors();
3339 // Parse tuple struct or enum pattern
3340 if self.look_ahead(1, |t| *t == token::DotDot) {
3341 // This is a "top constructor only" pat
3344 try!(self.expect(&token::CloseDelim(token::Paren)));
3345 pat = PatEnum(path, None);
3347 let args = try!(self.parse_enum_variant_seq(
3348 &token::OpenDelim(token::Paren),
3349 &token::CloseDelim(token::Paren),
3350 seq_sep_trailing_allowed(token::Comma),
3351 |p| p.parse_pat_nopanic()));
3352 pat = PatEnum(path, Some(args));
3355 _ if qself.is_some() => {
3356 // Parse qualified path
3357 pat = PatQPath(qself.unwrap(), path);
3360 // Parse nullary enum
3361 pat = PatEnum(path, Some(vec![]));
3366 // Try to parse everything else as literal with optional minus
3367 let begin = try!(self.parse_literal_maybe_minus());
3368 if try!(self.eat(&token::DotDotDot)) {
3369 let end = try!(self.parse_pat_range_end());
3370 pat = PatRange(begin, end);
3372 pat = PatLit(begin);
3378 let hi = self.last_span.hi;
3380 id: ast::DUMMY_NODE_ID,
3382 span: mk_sp(lo, hi),
3386 /// Parse ident or ident @ pat
3387 /// used by the copy foo and ref foo patterns to give a good
3388 /// error message when parsing mistakes like ref foo(a,b)
3389 fn parse_pat_ident(&mut self,
3390 binding_mode: ast::BindingMode)
3391 -> PResult<ast::Pat_> {
3392 if !self.token.is_plain_ident() {
3393 let span = self.span;
3394 let tok_str = self.this_token_to_string();
3395 return Err(self.span_fatal(span,
3396 &format!("expected identifier, found `{}`", tok_str)))
3398 let ident = try!(self.parse_ident());
3399 let last_span = self.last_span;
3400 let name = codemap::Spanned{span: last_span, node: ident};
3401 let sub = if try!(self.eat(&token::At) ){
3402 Some(try!(self.parse_pat_nopanic()))
3407 // just to be friendly, if they write something like
3409 // we end up here with ( as the current token. This shortly
3410 // leads to a parse error. Note that if there is no explicit
3411 // binding mode then we do not end up here, because the lookahead
3412 // will direct us over to parse_enum_variant()
3413 if self.token == token::OpenDelim(token::Paren) {
3414 let last_span = self.last_span;
3415 return Err(self.span_fatal(
3417 "expected identifier, found enum pattern"))
3420 Ok(PatIdent(binding_mode, name, sub))
3423 /// Parse a local variable declaration
3424 fn parse_local(&mut self) -> PResult<P<Local>> {
3425 let lo = self.span.lo;
3426 let pat = try!(self.parse_pat_nopanic());
3429 if try!(self.eat(&token::Colon) ){
3430 ty = Some(try!(self.parse_ty_sum()));
3432 let init = try!(self.parse_initializer());
3437 id: ast::DUMMY_NODE_ID,
3438 span: mk_sp(lo, self.last_span.hi),
3442 /// Parse a "let" stmt
3443 fn parse_let(&mut self) -> PResult<P<Decl>> {
3444 let lo = self.span.lo;
3445 let local = try!(self.parse_local());
3446 Ok(P(spanned(lo, self.last_span.hi, DeclLocal(local))))
3449 /// Parse a structure field
3450 fn parse_name_and_ty(&mut self, pr: Visibility,
3451 attrs: Vec<Attribute> ) -> PResult<StructField> {
3453 Inherited => self.span.lo,
3454 Public => self.last_span.lo,
3456 if !self.token.is_plain_ident() {
3457 return Err(self.fatal("expected ident"));
3459 let name = try!(self.parse_ident());
3460 try!(self.expect(&token::Colon));
3461 let ty = try!(self.parse_ty_sum());
3462 Ok(spanned(lo, self.last_span.hi, ast::StructField_ {
3463 kind: NamedField(name, pr),
3464 id: ast::DUMMY_NODE_ID,
3470 /// Emit an expected item after attributes error.
3471 fn expected_item_err(&self, attrs: &[Attribute]) {
3472 let message = match attrs.last() {
3473 Some(&Attribute { node: ast::Attribute_ { is_sugared_doc: true, .. }, .. }) => {
3474 "expected item after doc comment"
3476 _ => "expected item after attributes",
3479 self.span_err(self.last_span, message);
3482 /// Parse a statement. may include decl.
3483 pub fn parse_stmt_nopanic(&mut self) -> PResult<Option<P<Stmt>>> {
3484 Ok(try!(self.parse_stmt_()).map(P))
3487 fn parse_stmt_(&mut self) -> PResult<Option<Stmt>> {
3488 maybe_whole!(Some deref self, NtStmt);
3490 fn check_expected_item(p: &mut Parser, attrs: &[Attribute]) {
3491 // If we have attributes then we should have an item
3492 if !attrs.is_empty() {
3493 p.expected_item_err(attrs);
3497 let attrs = self.parse_outer_attributes();
3498 let lo = self.span.lo;
3500 Ok(Some(if self.check_keyword(keywords::Let) {
3501 check_expected_item(self, &attrs);
3502 try!(self.expect_keyword(keywords::Let));
3503 let decl = try!(self.parse_let());
3504 spanned(lo, decl.span.hi, StmtDecl(decl, ast::DUMMY_NODE_ID))
3505 } else if self.token.is_ident()
3506 && !self.token.is_any_keyword()
3507 && self.look_ahead(1, |t| *t == token::Not) {
3508 // it's a macro invocation:
3510 check_expected_item(self, &attrs);
3512 // Potential trouble: if we allow macros with paths instead of
3513 // idents, we'd need to look ahead past the whole path here...
3514 let pth = try!(self.parse_path(NoTypesAllowed));
3517 let id = match self.token {
3518 token::OpenDelim(_) => token::special_idents::invalid, // no special identifier
3519 _ => try!(self.parse_ident()),
3522 // check that we're pointing at delimiters (need to check
3523 // again after the `if`, because of `parse_ident`
3524 // consuming more tokens).
3525 let delim = match self.token {
3526 token::OpenDelim(delim) => delim,
3528 // we only expect an ident if we didn't parse one
3530 let ident_str = if id.name == token::special_idents::invalid.name {
3535 let tok_str = self.this_token_to_string();
3536 return Err(self.fatal(&format!("expected {}`(` or `{{`, found `{}`",
3542 let tts = try!(self.parse_unspanned_seq(
3543 &token::OpenDelim(delim),
3544 &token::CloseDelim(delim),
3546 |p| p.parse_token_tree()
3548 let hi = self.last_span.hi;
3550 let style = if delim == token::Brace {
3553 MacStmtWithoutBraces
3556 if id.name == token::special_idents::invalid.name {
3558 StmtMac(P(spanned(lo,
3560 MacInvocTT(pth, tts, EMPTY_CTXT))),
3563 // if it has a special ident, it's definitely an item
3565 // Require a semicolon or braces.
3566 if style != MacStmtWithBraces {
3567 if !try!(self.eat(&token::Semi) ){
3568 let last_span = self.last_span;
3569 self.span_err(last_span,
3570 "macros that expand to items must \
3571 either be surrounded with braces or \
3572 followed by a semicolon");
3575 spanned(lo, hi, StmtDecl(
3576 P(spanned(lo, hi, DeclItem(
3578 lo, hi, id /*id is good here*/,
3579 ItemMac(spanned(lo, hi, MacInvocTT(pth, tts, EMPTY_CTXT))),
3580 Inherited, Vec::new(/*no attrs*/))))),
3581 ast::DUMMY_NODE_ID))
3584 match try!(self.parse_item_(attrs, false)) {
3587 let decl = P(spanned(lo, hi, DeclItem(i)));
3588 spanned(lo, hi, StmtDecl(decl, ast::DUMMY_NODE_ID))
3591 // Do not attempt to parse an expression if we're done here.
3592 if self.token == token::Semi {
3597 if self.token == token::CloseDelim(token::Brace) {
3601 // Remainder are line-expr stmts.
3602 let e = try!(self.parse_expr_res(Restrictions::RESTRICTION_STMT_EXPR));
3603 spanned(lo, e.span.hi, StmtExpr(e, ast::DUMMY_NODE_ID))
3609 /// Is this expression a successfully-parsed statement?
3610 fn expr_is_complete(&mut self, e: &Expr) -> bool {
3611 self.restrictions.contains(Restrictions::RESTRICTION_STMT_EXPR) &&
3612 !classify::expr_requires_semi_to_be_stmt(e)
3615 /// Parse a block. No inner attrs are allowed.
3616 pub fn parse_block(&mut self) -> PResult<P<Block>> {
3617 maybe_whole!(no_clone self, NtBlock);
3619 let lo = self.span.lo;
3621 if !try!(self.eat(&token::OpenDelim(token::Brace)) ){
3623 let tok = self.this_token_to_string();
3624 return Err(self.span_fatal_help(sp,
3625 &format!("expected `{{`, found `{}`", tok),
3626 "place this code inside a block"));
3629 self.parse_block_tail(lo, DefaultBlock)
3632 /// Parse a block. Inner attrs are allowed.
3633 fn parse_inner_attrs_and_block(&mut self) -> PResult<(Vec<Attribute>, P<Block>)> {
3634 maybe_whole!(pair_empty self, NtBlock);
3636 let lo = self.span.lo;
3637 try!(self.expect(&token::OpenDelim(token::Brace)));
3638 Ok((self.parse_inner_attributes(),
3639 try!(self.parse_block_tail(lo, DefaultBlock))))
3642 /// Parse the rest of a block expression or function body
3643 /// Precondition: already parsed the '{'.
3644 fn parse_block_tail(&mut self, lo: BytePos, s: BlockCheckMode) -> PResult<P<Block>> {
3645 let mut stmts = vec![];
3646 let mut expr = None;
3648 while !try!(self.eat(&token::CloseDelim(token::Brace))) {
3649 let Spanned {node, span} = if let Some(s) = try!(self.parse_stmt_()) {
3652 // Found only `;` or `}`.
3657 try!(self.handle_expression_like_statement(e, span, &mut stmts, &mut expr));
3659 StmtMac(mac, MacStmtWithoutBraces) => {
3660 // statement macro without braces; might be an
3661 // expr depending on whether a semicolon follows
3664 stmts.push(P(Spanned {
3665 node: StmtMac(mac, MacStmtWithSemicolon),
3666 span: mk_sp(span.lo, self.span.hi),
3671 let e = self.mk_mac_expr(span.lo, span.hi,
3672 mac.and_then(|m| m.node));
3673 let e = try!(self.parse_dot_or_call_expr_with(e));
3674 let e = try!(self.parse_more_binops(e, 0));
3675 let e = try!(self.parse_assign_expr_with(e));
3676 try!(self.handle_expression_like_statement(
3684 StmtMac(m, style) => {
3685 // statement macro; might be an expr
3688 stmts.push(P(Spanned {
3689 node: StmtMac(m, MacStmtWithSemicolon),
3690 span: mk_sp(span.lo, self.span.hi),
3694 token::CloseDelim(token::Brace) => {
3695 // if a block ends in `m!(arg)` without
3696 // a `;`, it must be an expr
3697 expr = Some(self.mk_mac_expr(span.lo, span.hi,
3698 m.and_then(|x| x.node)));
3701 stmts.push(P(Spanned {
3702 node: StmtMac(m, style),
3708 _ => { // all other kinds of statements:
3709 let mut hi = span.hi;
3710 if classify::stmt_ends_with_semi(&node) {
3711 try!(self.commit_stmt_expecting(token::Semi));
3712 hi = self.last_span.hi;
3715 stmts.push(P(Spanned {
3717 span: mk_sp(span.lo, hi)
3726 id: ast::DUMMY_NODE_ID,
3728 span: mk_sp(lo, self.last_span.hi),
3732 fn handle_expression_like_statement(
3736 stmts: &mut Vec<P<Stmt>>,
3737 last_block_expr: &mut Option<P<Expr>>) -> PResult<()> {
3738 // expression without semicolon
3739 if classify::expr_requires_semi_to_be_stmt(&*e) {
3740 // Just check for errors and recover; do not eat semicolon yet.
3741 try!(self.commit_stmt(&[],
3742 &[token::Semi, token::CloseDelim(token::Brace)]));
3748 let span_with_semi = Span {
3750 hi: self.last_span.hi,
3751 expn_id: span.expn_id,
3753 stmts.push(P(Spanned {
3754 node: StmtSemi(e, ast::DUMMY_NODE_ID),
3755 span: span_with_semi,
3758 token::CloseDelim(token::Brace) => *last_block_expr = Some(e),
3760 stmts.push(P(Spanned {
3761 node: StmtExpr(e, ast::DUMMY_NODE_ID),
3769 // Parses a sequence of bounds if a `:` is found,
3770 // otherwise returns empty list.
3771 fn parse_colon_then_ty_param_bounds(&mut self,
3772 mode: BoundParsingMode)
3773 -> PResult<OwnedSlice<TyParamBound>>
3775 if !try!(self.eat(&token::Colon) ){
3776 Ok(OwnedSlice::empty())
3778 self.parse_ty_param_bounds(mode)
3782 // matches bounds = ( boundseq )?
3783 // where boundseq = ( polybound + boundseq ) | polybound
3784 // and polybound = ( 'for' '<' 'region '>' )? bound
3785 // and bound = 'region | trait_ref
3786 fn parse_ty_param_bounds(&mut self,
3787 mode: BoundParsingMode)
3788 -> PResult<OwnedSlice<TyParamBound>>
3790 let mut result = vec!();
3792 let question_span = self.span;
3793 let ate_question = try!(self.eat(&token::Question));
3795 token::Lifetime(lifetime) => {
3797 self.span_err(question_span,
3798 "`?` may only modify trait bounds, not lifetime bounds");
3800 result.push(RegionTyParamBound(ast::Lifetime {
3801 id: ast::DUMMY_NODE_ID,
3807 token::ModSep | token::Ident(..) => {
3808 let poly_trait_ref = try!(self.parse_poly_trait_ref());
3809 let modifier = if ate_question {
3810 if mode == BoundParsingMode::Modified {
3811 TraitBoundModifier::Maybe
3813 self.span_err(question_span,
3815 TraitBoundModifier::None
3818 TraitBoundModifier::None
3820 result.push(TraitTyParamBound(poly_trait_ref, modifier))
3825 if !try!(self.eat(&token::BinOp(token::Plus)) ){
3830 return Ok(OwnedSlice::from_vec(result));
3833 /// Matches typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?
3834 fn parse_ty_param(&mut self) -> PResult<TyParam> {
3835 let span = self.span;
3836 let ident = try!(self.parse_ident());
3838 let bounds = try!(self.parse_colon_then_ty_param_bounds(BoundParsingMode::Modified));
3840 let default = if self.check(&token::Eq) {
3842 Some(try!(self.parse_ty_sum()))
3849 id: ast::DUMMY_NODE_ID,
3856 /// Parse a set of optional generic type parameter declarations. Where
3857 /// clauses are not parsed here, and must be added later via
3858 /// `parse_where_clause()`.
3860 /// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
3861 /// | ( < lifetimes , typaramseq ( , )? > )
3862 /// where typaramseq = ( typaram ) | ( typaram , typaramseq )
3863 pub fn parse_generics(&mut self) -> PResult<ast::Generics> {
3864 maybe_whole!(self, NtGenerics);
3866 if try!(self.eat(&token::Lt) ){
3867 let lifetime_defs = try!(self.parse_lifetime_defs());
3868 let mut seen_default = false;
3869 let ty_params = try!(self.parse_seq_to_gt(Some(token::Comma), |p| {
3870 try!(p.forbid_lifetime());
3871 let ty_param = try!(p.parse_ty_param());
3872 if ty_param.default.is_some() {
3873 seen_default = true;
3874 } else if seen_default {
3875 let last_span = p.last_span;
3876 p.span_err(last_span,
3877 "type parameters with a default must be trailing");
3882 lifetimes: lifetime_defs,
3883 ty_params: ty_params,
3884 where_clause: WhereClause {
3885 id: ast::DUMMY_NODE_ID,
3886 predicates: Vec::new(),
3890 Ok(ast_util::empty_generics())
3894 fn parse_generic_values_after_lt(&mut self) -> PResult<(Vec<ast::Lifetime>,
3896 Vec<P<TypeBinding>>)> {
3897 let span_lo = self.span.lo;
3898 let lifetimes = try!(self.parse_lifetimes(token::Comma));
3900 let missing_comma = !lifetimes.is_empty() &&
3901 !self.token.is_like_gt() &&
3903 .as_ref().map_or(true,
3904 |x| &**x != &token::Comma);
3908 let msg = format!("expected `,` or `>` after lifetime \
3910 self.this_token_to_string());
3911 self.span_err(self.span, &msg);
3913 let span_hi = self.span.hi;
3914 let span_hi = if self.parse_ty_nopanic().is_ok() {
3920 let msg = format!("did you mean a single argument type &'a Type, \
3921 or did you mean the comma-separated arguments \
3923 self.span_note(mk_sp(span_lo, span_hi), &msg);
3925 self.abort_if_errors()
3928 // First parse types.
3929 let (types, returned) = try!(self.parse_seq_to_gt_or_return(
3932 try!(p.forbid_lifetime());
3933 if p.look_ahead(1, |t| t == &token::Eq) {
3936 Ok(Some(try!(p.parse_ty_sum())))
3941 // If we found the `>`, don't continue.
3943 return Ok((lifetimes, types.into_vec(), Vec::new()));
3946 // Then parse type bindings.
3947 let bindings = try!(self.parse_seq_to_gt(
3950 try!(p.forbid_lifetime());
3952 let ident = try!(p.parse_ident());
3953 let found_eq = try!(p.eat(&token::Eq));
3956 p.span_warn(span, "whoops, no =?");
3958 let ty = try!(p.parse_ty_nopanic());
3959 let hi = ty.span.hi;
3960 let span = mk_sp(lo, hi);
3961 return Ok(P(TypeBinding{id: ast::DUMMY_NODE_ID,
3968 Ok((lifetimes, types.into_vec(), bindings.into_vec()))
3971 fn forbid_lifetime(&mut self) -> PResult<()> {
3972 if self.token.is_lifetime() {
3973 let span = self.span;
3974 return Err(self.span_fatal(span, "lifetime parameters must be declared \
3975 prior to type parameters"))
3980 /// Parses an optional `where` clause and places it in `generics`.
3983 /// where T : Trait<U, V> + 'b, 'a : 'b
3985 pub fn parse_where_clause(&mut self) -> PResult<ast::WhereClause> {
3986 maybe_whole!(self, NtWhereClause);
3988 let mut where_clause = WhereClause {
3989 id: ast::DUMMY_NODE_ID,
3990 predicates: Vec::new(),
3993 if !try!(self.eat_keyword(keywords::Where)) {
3994 return Ok(where_clause);
3997 let mut parsed_something = false;
3999 let lo = self.span.lo;
4001 token::OpenDelim(token::Brace) => {
4005 token::Lifetime(..) => {
4006 let bounded_lifetime =
4007 try!(self.parse_lifetime());
4009 try!(self.eat(&token::Colon));
4012 try!(self.parse_lifetimes(token::BinOp(token::Plus)));
4014 let hi = self.last_span.hi;
4015 let span = mk_sp(lo, hi);
4017 where_clause.predicates.push(ast::WherePredicate::RegionPredicate(
4018 ast::WhereRegionPredicate {
4020 lifetime: bounded_lifetime,
4025 parsed_something = true;
4029 let bound_lifetimes = if try!(self.eat_keyword(keywords::For) ){
4030 // Higher ranked constraint.
4031 try!(self.expect(&token::Lt));
4032 let lifetime_defs = try!(self.parse_lifetime_defs());
4033 try!(self.expect_gt());
4039 let bounded_ty = try!(self.parse_ty_nopanic());
4041 if try!(self.eat(&token::Colon) ){
4042 let bounds = try!(self.parse_ty_param_bounds(BoundParsingMode::Bare));
4043 let hi = self.last_span.hi;
4044 let span = mk_sp(lo, hi);
4046 if bounds.is_empty() {
4048 "each predicate in a `where` clause must have \
4049 at least one bound in it");
4052 where_clause.predicates.push(ast::WherePredicate::BoundPredicate(
4053 ast::WhereBoundPredicate {
4055 bound_lifetimes: bound_lifetimes,
4056 bounded_ty: bounded_ty,
4060 parsed_something = true;
4061 } else if try!(self.eat(&token::Eq) ){
4062 // let ty = try!(self.parse_ty_nopanic());
4063 let hi = self.last_span.hi;
4064 let span = mk_sp(lo, hi);
4065 // where_clause.predicates.push(
4066 // ast::WherePredicate::EqPredicate(ast::WhereEqPredicate {
4067 // id: ast::DUMMY_NODE_ID,
4069 // path: panic!("NYI"), //bounded_ty,
4072 // parsed_something = true;
4075 "equality constraints are not yet supported \
4076 in where clauses (#20041)");
4078 let last_span = self.last_span;
4079 self.span_err(last_span,
4080 "unexpected token in `where` clause");
4085 if !try!(self.eat(&token::Comma) ){
4090 if !parsed_something {
4091 let last_span = self.last_span;
4092 self.span_err(last_span,
4093 "a `where` clause must have at least one predicate \
4100 fn parse_fn_args(&mut self, named_args: bool, allow_variadic: bool)
4101 -> PResult<(Vec<Arg> , bool)> {
4103 let mut args: Vec<Option<Arg>> =
4104 try!(self.parse_unspanned_seq(
4105 &token::OpenDelim(token::Paren),
4106 &token::CloseDelim(token::Paren),
4107 seq_sep_trailing_allowed(token::Comma),
4109 if p.token == token::DotDotDot {
4112 if p.token != token::CloseDelim(token::Paren) {
4114 return Err(p.span_fatal(span,
4115 "`...` must be last in argument list for variadic function"))
4119 return Err(p.span_fatal(span,
4120 "only foreign functions are allowed to be variadic"))
4124 Ok(Some(try!(p.parse_arg_general(named_args))))
4129 let variadic = match args.pop() {
4132 // Need to put back that last arg
4139 if variadic && args.is_empty() {
4141 "variadic function must be declared with at least one named argument");
4144 let args = args.into_iter().map(|x| x.unwrap()).collect();
4146 Ok((args, variadic))
4149 /// Parse the argument list and result type of a function declaration
4150 pub fn parse_fn_decl(&mut self, allow_variadic: bool) -> PResult<P<FnDecl>> {
4152 let (args, variadic) = try!(self.parse_fn_args(true, allow_variadic));
4153 let ret_ty = try!(self.parse_ret_ty());
4162 fn is_self_ident(&mut self) -> bool {
4164 token::Ident(id, token::Plain) => id.name == special_idents::self_.name,
4169 fn expect_self_ident(&mut self) -> PResult<ast::Ident> {
4171 token::Ident(id, token::Plain) if id.name == special_idents::self_.name => {
4176 let token_str = self.this_token_to_string();
4177 return Err(self.fatal(&format!("expected `self`, found `{}`",
4183 fn is_self_type_ident(&mut self) -> bool {
4185 token::Ident(id, token::Plain) => id.name == special_idents::type_self.name,
4190 fn expect_self_type_ident(&mut self) -> PResult<ast::Ident> {
4192 token::Ident(id, token::Plain) if id.name == special_idents::type_self.name => {
4197 let token_str = self.this_token_to_string();
4198 Err(self.fatal(&format!("expected `Self`, found `{}`",
4204 /// Parse the argument list and result type of a function
4205 /// that may have a self type.
4206 fn parse_fn_decl_with_self<F>(&mut self,
4207 parse_arg_fn: F) -> PResult<(ExplicitSelf, P<FnDecl>)> where
4208 F: FnMut(&mut Parser) -> PResult<Arg>,
4210 fn maybe_parse_borrowed_explicit_self(this: &mut Parser)
4211 -> PResult<ast::ExplicitSelf_> {
4212 // The following things are possible to see here:
4217 // fn(&'lt mut self)
4219 // We already know that the current token is `&`.
4221 if this.look_ahead(1, |t| t.is_keyword(keywords::SelfValue)) {
4223 Ok(SelfRegion(None, MutImmutable, try!(this.expect_self_ident())))
4224 } else if this.look_ahead(1, |t| t.is_mutability()) &&
4225 this.look_ahead(2, |t| t.is_keyword(keywords::SelfValue)) {
4227 let mutability = try!(this.parse_mutability());
4228 Ok(SelfRegion(None, mutability, try!(this.expect_self_ident())))
4229 } else if this.look_ahead(1, |t| t.is_lifetime()) &&
4230 this.look_ahead(2, |t| t.is_keyword(keywords::SelfValue)) {
4232 let lifetime = try!(this.parse_lifetime());
4233 Ok(SelfRegion(Some(lifetime), MutImmutable, try!(this.expect_self_ident())))
4234 } else if this.look_ahead(1, |t| t.is_lifetime()) &&
4235 this.look_ahead(2, |t| t.is_mutability()) &&
4236 this.look_ahead(3, |t| t.is_keyword(keywords::SelfValue)) {
4238 let lifetime = try!(this.parse_lifetime());
4239 let mutability = try!(this.parse_mutability());
4240 Ok(SelfRegion(Some(lifetime), mutability, try!(this.expect_self_ident())))
4246 try!(self.expect(&token::OpenDelim(token::Paren)));
4248 // A bit of complexity and lookahead is needed here in order to be
4249 // backwards compatible.
4250 let lo = self.span.lo;
4251 let mut self_ident_lo = self.span.lo;
4252 let mut self_ident_hi = self.span.hi;
4254 let mut mutbl_self = MutImmutable;
4255 let explicit_self = match self.token {
4256 token::BinOp(token::And) => {
4257 let eself = try!(maybe_parse_borrowed_explicit_self(self));
4258 self_ident_lo = self.last_span.lo;
4259 self_ident_hi = self.last_span.hi;
4262 token::BinOp(token::Star) => {
4263 // Possibly "*self" or "*mut self" -- not supported. Try to avoid
4264 // emitting cryptic "unexpected token" errors.
4266 let _mutability = if self.token.is_mutability() {
4267 try!(self.parse_mutability())
4271 if self.is_self_ident() {
4272 let span = self.span;
4273 self.span_err(span, "cannot pass self by raw pointer");
4276 // error case, making bogus self ident:
4277 SelfValue(special_idents::self_)
4279 token::Ident(..) => {
4280 if self.is_self_ident() {
4281 let self_ident = try!(self.expect_self_ident());
4283 // Determine whether this is the fully explicit form, `self:
4285 if try!(self.eat(&token::Colon) ){
4286 SelfExplicit(try!(self.parse_ty_sum()), self_ident)
4288 SelfValue(self_ident)
4290 } else if self.token.is_mutability() &&
4291 self.look_ahead(1, |t| t.is_keyword(keywords::SelfValue)) {
4292 mutbl_self = try!(self.parse_mutability());
4293 let self_ident = try!(self.expect_self_ident());
4295 // Determine whether this is the fully explicit form,
4297 if try!(self.eat(&token::Colon) ){
4298 SelfExplicit(try!(self.parse_ty_sum()), self_ident)
4300 SelfValue(self_ident)
4309 let explicit_self_sp = mk_sp(self_ident_lo, self_ident_hi);
4311 // shared fall-through for the three cases below. borrowing prevents simply
4312 // writing this as a closure
4313 macro_rules! parse_remaining_arguments {
4316 // If we parsed a self type, expect a comma before the argument list.
4320 let sep = seq_sep_trailing_allowed(token::Comma);
4321 let mut fn_inputs = try!(self.parse_seq_to_before_end(
4322 &token::CloseDelim(token::Paren),
4326 fn_inputs.insert(0, Arg::new_self(explicit_self_sp, mutbl_self, $self_id));
4329 token::CloseDelim(token::Paren) => {
4330 vec!(Arg::new_self(explicit_self_sp, mutbl_self, $self_id))
4333 let token_str = self.this_token_to_string();
4334 return Err(self.fatal(&format!("expected `,` or `)`, found `{}`",
4341 let fn_inputs = match explicit_self {
4343 let sep = seq_sep_trailing_allowed(token::Comma);
4344 try!(self.parse_seq_to_before_end(&token::CloseDelim(token::Paren),
4347 SelfValue(id) => parse_remaining_arguments!(id),
4348 SelfRegion(_,_,id) => parse_remaining_arguments!(id),
4349 SelfExplicit(_,id) => parse_remaining_arguments!(id),
4353 try!(self.expect(&token::CloseDelim(token::Paren)));
4355 let hi = self.span.hi;
4357 let ret_ty = try!(self.parse_ret_ty());
4359 let fn_decl = P(FnDecl {
4365 Ok((spanned(lo, hi, explicit_self), fn_decl))
4368 // parse the |arg, arg| header on a lambda
4369 fn parse_fn_block_decl(&mut self) -> PResult<P<FnDecl>> {
4370 let inputs_captures = {
4371 if try!(self.eat(&token::OrOr) ){
4374 try!(self.expect(&token::BinOp(token::Or)));
4375 try!(self.parse_obsolete_closure_kind());
4376 let args = try!(self.parse_seq_to_before_end(
4377 &token::BinOp(token::Or),
4378 seq_sep_trailing_allowed(token::Comma),
4379 |p| p.parse_fn_block_arg()
4385 let output = try!(self.parse_ret_ty());
4388 inputs: inputs_captures,
4394 /// Parse the name and optional generic types of a function header.
4395 fn parse_fn_header(&mut self) -> PResult<(Ident, ast::Generics)> {
4396 let id = try!(self.parse_ident());
4397 let generics = try!(self.parse_generics());
4401 fn mk_item(&mut self, lo: BytePos, hi: BytePos, ident: Ident,
4402 node: Item_, vis: Visibility,
4403 attrs: Vec<Attribute>) -> P<Item> {
4407 id: ast::DUMMY_NODE_ID,
4414 /// Parse an item-position function declaration.
4415 fn parse_item_fn(&mut self,
4417 constness: Constness,
4419 -> PResult<ItemInfo> {
4420 let (ident, mut generics) = try!(self.parse_fn_header());
4421 let decl = try!(self.parse_fn_decl(false));
4422 generics.where_clause = try!(self.parse_where_clause());
4423 let (inner_attrs, body) = try!(self.parse_inner_attrs_and_block());
4424 Ok((ident, ItemFn(decl, unsafety, constness, abi, generics, body), Some(inner_attrs)))
4427 /// true if we are looking at `const ID`, false for things like `const fn` etc
4428 pub fn is_const_item(&mut self) -> bool {
4429 self.token.is_keyword(keywords::Const) &&
4430 !self.look_ahead(1, |t| t.is_keyword(keywords::Fn))
4433 /// parses all the "front matter" for a `fn` declaration, up to
4434 /// and including the `fn` keyword:
4440 pub fn parse_fn_front_matter(&mut self) -> PResult<(ast::Constness, ast::Unsafety, abi::Abi)> {
4441 let is_const_fn = try!(self.eat_keyword(keywords::Const));
4442 let (constness, unsafety, abi) = if is_const_fn {
4443 (Constness::Const, Unsafety::Normal, abi::Rust)
4445 let unsafety = try!(self.parse_unsafety());
4446 let abi = if try!(self.eat_keyword(keywords::Extern)) {
4447 try!(self.parse_opt_abi()).unwrap_or(abi::C)
4451 (Constness::NotConst, unsafety, abi)
4453 try!(self.expect_keyword(keywords::Fn));
4454 Ok((constness, unsafety, abi))
4457 /// Parse an impl item.
4458 pub fn parse_impl_item(&mut self) -> PResult<P<ImplItem>> {
4459 maybe_whole!(no_clone self, NtImplItem);
4461 let mut attrs = self.parse_outer_attributes();
4462 let lo = self.span.lo;
4463 let vis = try!(self.parse_visibility());
4464 let (name, node) = if try!(self.eat_keyword(keywords::Type)) {
4465 let name = try!(self.parse_ident());
4466 try!(self.expect(&token::Eq));
4467 let typ = try!(self.parse_ty_sum());
4468 try!(self.expect(&token::Semi));
4469 (name, TypeImplItem(typ))
4470 } else if self.is_const_item() {
4471 try!(self.expect_keyword(keywords::Const));
4472 let name = try!(self.parse_ident());
4473 try!(self.expect(&token::Colon));
4474 let typ = try!(self.parse_ty_sum());
4475 try!(self.expect(&token::Eq));
4476 let expr = try!(self.parse_expr_nopanic());
4477 try!(self.commit_expr_expecting(&expr, token::Semi));
4478 (name, ConstImplItem(typ, expr))
4480 let (name, inner_attrs, node) = try!(self.parse_impl_method(vis));
4481 attrs.extend(inner_attrs);
4486 id: ast::DUMMY_NODE_ID,
4487 span: mk_sp(lo, self.last_span.hi),
4495 fn complain_if_pub_macro(&mut self, visa: Visibility, span: Span) {
4498 self.span_err(span, "can't qualify macro invocation with `pub`");
4499 self.fileline_help(span, "try adjusting the macro to put `pub` inside \
4506 /// Parse a method or a macro invocation in a trait impl.
4507 fn parse_impl_method(&mut self, vis: Visibility)
4508 -> PResult<(Ident, Vec<ast::Attribute>, ast::ImplItem_)> {
4509 // code copied from parse_macro_use_or_failure... abstraction!
4510 if !self.token.is_any_keyword()
4511 && self.look_ahead(1, |t| *t == token::Not)
4512 && (self.look_ahead(2, |t| *t == token::OpenDelim(token::Paren))
4513 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))) {
4516 let last_span = self.last_span;
4517 self.complain_if_pub_macro(vis, last_span);
4519 let pth = try!(self.parse_path(NoTypesAllowed));
4520 try!(self.expect(&token::Not));
4522 // eat a matched-delimiter token tree:
4523 let delim = try!(self.expect_open_delim());
4524 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
4526 |p| p.parse_token_tree()));
4527 let m_ = ast::MacInvocTT(pth, tts, EMPTY_CTXT);
4528 let m: ast::Mac = codemap::Spanned { node: m_,
4529 span: mk_sp(self.span.lo,
4531 if delim != token::Brace {
4532 try!(self.expect(&token::Semi))
4534 Ok((token::special_idents::invalid, vec![], ast::MacImplItem(m)))
4536 let (constness, unsafety, abi) = try!(self.parse_fn_front_matter());
4537 let ident = try!(self.parse_ident());
4538 let mut generics = try!(self.parse_generics());
4539 let (explicit_self, decl) = try!(self.parse_fn_decl_with_self(|p| {
4542 generics.where_clause = try!(self.parse_where_clause());
4543 let (inner_attrs, body) = try!(self.parse_inner_attrs_and_block());
4544 Ok((ident, inner_attrs, MethodImplItem(ast::MethodSig {
4547 explicit_self: explicit_self,
4549 constness: constness,
4555 /// Parse trait Foo { ... }
4556 fn parse_item_trait(&mut self, unsafety: Unsafety) -> PResult<ItemInfo> {
4558 let ident = try!(self.parse_ident());
4559 let mut tps = try!(self.parse_generics());
4561 // Parse supertrait bounds.
4562 let bounds = try!(self.parse_colon_then_ty_param_bounds(BoundParsingMode::Bare));
4564 tps.where_clause = try!(self.parse_where_clause());
4566 let meths = try!(self.parse_trait_items());
4567 Ok((ident, ItemTrait(unsafety, tps, bounds, meths), None))
4570 /// Parses items implementations variants
4571 /// impl<T> Foo { ... }
4572 /// impl<T> ToString for &'static T { ... }
4573 /// impl Send for .. {}
4574 fn parse_item_impl(&mut self, unsafety: ast::Unsafety) -> PResult<ItemInfo> {
4575 let impl_span = self.span;
4577 // First, parse type parameters if necessary.
4578 let mut generics = try!(self.parse_generics());
4580 // Special case: if the next identifier that follows is '(', don't
4581 // allow this to be parsed as a trait.
4582 let could_be_trait = self.token != token::OpenDelim(token::Paren);
4584 let neg_span = self.span;
4585 let polarity = if try!(self.eat(&token::Not) ){
4586 ast::ImplPolarity::Negative
4588 ast::ImplPolarity::Positive
4592 let mut ty = try!(self.parse_ty_sum());
4594 // Parse traits, if necessary.
4595 let opt_trait = if could_be_trait && try!(self.eat_keyword(keywords::For) ){
4596 // New-style trait. Reinterpret the type as a trait.
4598 TyPath(None, ref path) => {
4600 path: (*path).clone(),
4605 self.span_err(ty.span, "not a trait");
4611 ast::ImplPolarity::Negative => {
4612 // This is a negated type implementation
4613 // `impl !MyType {}`, which is not allowed.
4614 self.span_err(neg_span, "inherent implementation can't be negated");
4621 if opt_trait.is_some() && try!(self.eat(&token::DotDot) ){
4622 if generics.is_parameterized() {
4623 self.span_err(impl_span, "default trait implementations are not \
4624 allowed to have generics");
4627 try!(self.expect(&token::OpenDelim(token::Brace)));
4628 try!(self.expect(&token::CloseDelim(token::Brace)));
4629 Ok((ast_util::impl_pretty_name(&opt_trait, None),
4630 ItemDefaultImpl(unsafety, opt_trait.unwrap()), None))
4632 if opt_trait.is_some() {
4633 ty = try!(self.parse_ty_sum());
4635 generics.where_clause = try!(self.parse_where_clause());
4637 try!(self.expect(&token::OpenDelim(token::Brace)));
4638 let attrs = self.parse_inner_attributes();
4640 let mut impl_items = vec![];
4641 while !try!(self.eat(&token::CloseDelim(token::Brace))) {
4642 impl_items.push(try!(self.parse_impl_item()));
4645 Ok((ast_util::impl_pretty_name(&opt_trait, Some(&*ty)),
4646 ItemImpl(unsafety, polarity, generics, opt_trait, ty, impl_items),
4651 /// Parse a::B<String,i32>
4652 fn parse_trait_ref(&mut self) -> PResult<TraitRef> {
4654 path: try!(self.parse_path(LifetimeAndTypesWithoutColons)),
4655 ref_id: ast::DUMMY_NODE_ID,
4659 fn parse_late_bound_lifetime_defs(&mut self) -> PResult<Vec<ast::LifetimeDef>> {
4660 if try!(self.eat_keyword(keywords::For) ){
4661 try!(self.expect(&token::Lt));
4662 let lifetime_defs = try!(self.parse_lifetime_defs());
4663 try!(self.expect_gt());
4670 /// Parse for<'l> a::B<String,i32>
4671 fn parse_poly_trait_ref(&mut self) -> PResult<PolyTraitRef> {
4672 let lo = self.span.lo;
4673 let lifetime_defs = try!(self.parse_late_bound_lifetime_defs());
4675 Ok(ast::PolyTraitRef {
4676 bound_lifetimes: lifetime_defs,
4677 trait_ref: try!(self.parse_trait_ref()),
4678 span: mk_sp(lo, self.last_span.hi),
4682 /// Parse struct Foo { ... }
4683 fn parse_item_struct(&mut self) -> PResult<ItemInfo> {
4684 let class_name = try!(self.parse_ident());
4685 let mut generics = try!(self.parse_generics());
4687 // There is a special case worth noting here, as reported in issue #17904.
4688 // If we are parsing a tuple struct it is the case that the where clause
4689 // should follow the field list. Like so:
4691 // struct Foo<T>(T) where T: Copy;
4693 // If we are parsing a normal record-style struct it is the case
4694 // that the where clause comes before the body, and after the generics.
4695 // So if we look ahead and see a brace or a where-clause we begin
4696 // parsing a record style struct.
4698 // Otherwise if we look ahead and see a paren we parse a tuple-style
4701 let (fields, ctor_id) = if self.token.is_keyword(keywords::Where) {
4702 generics.where_clause = try!(self.parse_where_clause());
4703 if try!(self.eat(&token::Semi)) {
4704 // If we see a: `struct Foo<T> where T: Copy;` style decl.
4705 (Vec::new(), Some(ast::DUMMY_NODE_ID))
4707 // If we see: `struct Foo<T> where T: Copy { ... }`
4708 (try!(self.parse_record_struct_body()), None)
4710 // No `where` so: `struct Foo<T>;`
4711 } else if try!(self.eat(&token::Semi) ){
4712 (Vec::new(), Some(ast::DUMMY_NODE_ID))
4713 // Record-style struct definition
4714 } else if self.token == token::OpenDelim(token::Brace) {
4715 let fields = try!(self.parse_record_struct_body());
4717 // Tuple-style struct definition with optional where-clause.
4718 } else if self.token == token::OpenDelim(token::Paren) {
4719 let fields = try!(self.parse_tuple_struct_body(&class_name, &mut generics));
4720 (fields, Some(ast::DUMMY_NODE_ID))
4722 let token_str = self.this_token_to_string();
4723 return Err(self.fatal(&format!("expected `where`, `{{`, `(`, or `;` after struct \
4724 name, found `{}`", token_str)))
4728 ItemStruct(P(ast::StructDef {
4735 pub fn parse_record_struct_body(&mut self) -> PResult<Vec<StructField>> {
4736 let mut fields = Vec::new();
4737 if try!(self.eat(&token::OpenDelim(token::Brace)) ){
4738 while self.token != token::CloseDelim(token::Brace) {
4739 fields.push(try!(self.parse_struct_decl_field(true)));
4744 let token_str = self.this_token_to_string();
4745 return Err(self.fatal(&format!("expected `where`, or `{{` after struct \
4753 pub fn parse_tuple_struct_body(&mut self,
4754 class_name: &ast::Ident,
4755 generics: &mut ast::Generics)
4756 -> PResult<Vec<StructField>> {
4757 // This is the case where we find `struct Foo<T>(T) where T: Copy;`
4758 // Unit like structs are handled in parse_item_struct function
4759 let fields = try!(self.parse_unspanned_seq(
4760 &token::OpenDelim(token::Paren),
4761 &token::CloseDelim(token::Paren),
4762 seq_sep_trailing_allowed(token::Comma),
4764 let attrs = p.parse_outer_attributes();
4766 let struct_field_ = ast::StructField_ {
4767 kind: UnnamedField(try!(p.parse_visibility())),
4768 id: ast::DUMMY_NODE_ID,
4769 ty: try!(p.parse_ty_sum()),
4772 Ok(spanned(lo, p.span.hi, struct_field_))
4775 if fields.is_empty() {
4776 return Err(self.fatal(&format!("unit-like struct definition should be \
4777 written as `struct {};`",
4781 generics.where_clause = try!(self.parse_where_clause());
4782 try!(self.expect(&token::Semi));
4786 /// Parse a structure field declaration
4787 pub fn parse_single_struct_field(&mut self,
4789 attrs: Vec<Attribute> )
4790 -> PResult<StructField> {
4791 let a_var = try!(self.parse_name_and_ty(vis, attrs));
4796 token::CloseDelim(token::Brace) => {}
4798 let span = self.span;
4799 let token_str = self.this_token_to_string();
4800 return Err(self.span_fatal_help(span,
4801 &format!("expected `,`, or `}}`, found `{}`",
4803 "struct fields should be separated by commas"))
4809 /// Parse an element of a struct definition
4810 fn parse_struct_decl_field(&mut self, allow_pub: bool) -> PResult<StructField> {
4812 let attrs = self.parse_outer_attributes();
4814 if try!(self.eat_keyword(keywords::Pub) ){
4816 let span = self.last_span;
4817 self.span_err(span, "`pub` is not allowed here");
4819 return self.parse_single_struct_field(Public, attrs);
4822 return self.parse_single_struct_field(Inherited, attrs);
4825 /// Parse visibility: PUB or nothing
4826 fn parse_visibility(&mut self) -> PResult<Visibility> {
4827 if try!(self.eat_keyword(keywords::Pub)) { Ok(Public) }
4828 else { Ok(Inherited) }
4831 /// Given a termination token, parse all of the items in a module
4832 fn parse_mod_items(&mut self, term: &token::Token, inner_lo: BytePos) -> PResult<Mod> {
4833 let mut items = vec![];
4834 while let Some(item) = try!(self.parse_item_nopanic()) {
4838 if !try!(self.eat(term)) {
4839 let token_str = self.this_token_to_string();
4840 return Err(self.fatal(&format!("expected item, found `{}`", token_str)));
4843 let hi = if self.span == codemap::DUMMY_SP {
4850 inner: mk_sp(inner_lo, hi),
4855 fn parse_item_const(&mut self, m: Option<Mutability>) -> PResult<ItemInfo> {
4856 let id = try!(self.parse_ident());
4857 try!(self.expect(&token::Colon));
4858 let ty = try!(self.parse_ty_sum());
4859 try!(self.expect(&token::Eq));
4860 let e = try!(self.parse_expr_nopanic());
4861 try!(self.commit_expr_expecting(&*e, token::Semi));
4862 let item = match m {
4863 Some(m) => ItemStatic(ty, m, e),
4864 None => ItemConst(ty, e),
4866 Ok((id, item, None))
4869 /// Parse a `mod <foo> { ... }` or `mod <foo>;` item
4870 fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<ItemInfo> {
4871 let id_span = self.span;
4872 let id = try!(self.parse_ident());
4873 if self.check(&token::Semi) {
4875 // This mod is in an external file. Let's go get it!
4876 let (m, attrs) = try!(self.eval_src_mod(id, outer_attrs, id_span));
4877 Ok((id, m, Some(attrs)))
4879 self.push_mod_path(id, outer_attrs);
4880 try!(self.expect(&token::OpenDelim(token::Brace)));
4881 let mod_inner_lo = self.span.lo;
4882 let old_owns_directory = self.owns_directory;
4883 self.owns_directory = true;
4884 let attrs = self.parse_inner_attributes();
4885 let m = try!(self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo));
4886 self.owns_directory = old_owns_directory;
4887 self.pop_mod_path();
4888 Ok((id, ItemMod(m), Some(attrs)))
4892 fn push_mod_path(&mut self, id: Ident, attrs: &[Attribute]) {
4893 let default_path = self.id_to_interned_str(id);
4894 let file_path = match ::attr::first_attr_value_str_by_name(attrs, "path") {
4896 None => default_path,
4898 self.mod_path_stack.push(file_path)
4901 fn pop_mod_path(&mut self) {
4902 self.mod_path_stack.pop().unwrap();
4905 pub fn submod_path_from_attr(attrs: &[ast::Attribute], dir_path: &Path) -> Option<PathBuf> {
4906 ::attr::first_attr_value_str_by_name(attrs, "path").map(|d| dir_path.join(&*d))
4909 /// Returns either a path to a module, or .
4910 pub fn default_submod_path(id: ast::Ident, dir_path: &Path, codemap: &CodeMap) -> ModulePath
4912 let mod_name = id.to_string();
4913 let default_path_str = format!("{}.rs", mod_name);
4914 let secondary_path_str = format!("{}/mod.rs", mod_name);
4915 let default_path = dir_path.join(&default_path_str);
4916 let secondary_path = dir_path.join(&secondary_path_str);
4917 let default_exists = codemap.file_exists(&default_path);
4918 let secondary_exists = codemap.file_exists(&secondary_path);
4920 let result = match (default_exists, secondary_exists) {
4921 (true, false) => Ok(ModulePathSuccess { path: default_path, owns_directory: false }),
4922 (false, true) => Ok(ModulePathSuccess { path: secondary_path, owns_directory: true }),
4923 (false, false) => Err(ModulePathError {
4924 err_msg: format!("file not found for module `{}`", mod_name),
4925 help_msg: format!("name the file either {} or {} inside the directory {:?}",
4928 dir_path.display()),
4930 (true, true) => Err(ModulePathError {
4931 err_msg: format!("file for module `{}` found at both {} and {}",
4934 secondary_path_str),
4935 help_msg: "delete or rename one of them to remove the ambiguity".to_owned(),
4941 path_exists: default_exists || secondary_exists,
4946 fn submod_path(&mut self,
4948 outer_attrs: &[ast::Attribute],
4949 id_sp: Span) -> PResult<ModulePathSuccess> {
4950 let mut prefix = PathBuf::from(&self.sess.codemap().span_to_filename(self.span));
4952 let mut dir_path = prefix;
4953 for part in &self.mod_path_stack {
4954 dir_path.push(&**part);
4957 if let Some(p) = Parser::submod_path_from_attr(outer_attrs, &dir_path) {
4958 return Ok(ModulePathSuccess { path: p, owns_directory: true });
4961 let paths = Parser::default_submod_path(id, &dir_path, self.sess.codemap());
4963 if !self.owns_directory {
4964 self.span_err(id_sp, "cannot declare a new module at this location");
4965 let this_module = match self.mod_path_stack.last() {
4966 Some(name) => name.to_string(),
4967 None => self.root_module_name.as_ref().unwrap().clone(),
4969 self.span_note(id_sp,
4970 &format!("maybe move this module `{0}` to its own directory \
4973 if paths.path_exists {
4974 self.span_note(id_sp,
4975 &format!("... or maybe `use` the module `{}` instead \
4976 of possibly redeclaring it",
4979 self.abort_if_errors();
4982 match paths.result {
4983 Ok(succ) => Ok(succ),
4984 Err(err) => Err(self.span_fatal_help(id_sp, &err.err_msg, &err.help_msg)),
4988 /// Read a module from a source file.
4989 fn eval_src_mod(&mut self,
4991 outer_attrs: &[ast::Attribute],
4993 -> PResult<(ast::Item_, Vec<ast::Attribute> )> {
4994 let ModulePathSuccess { path, owns_directory } = try!(self.submod_path(id,
4998 self.eval_src_mod_from_path(path,
5004 fn eval_src_mod_from_path(&mut self,
5006 owns_directory: bool,
5008 id_sp: Span) -> PResult<(ast::Item_, Vec<ast::Attribute> )> {
5009 let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
5010 match included_mod_stack.iter().position(|p| *p == path) {
5012 let mut err = String::from("circular modules: ");
5013 let len = included_mod_stack.len();
5014 for p in &included_mod_stack[i.. len] {
5015 err.push_str(&p.to_string_lossy());
5016 err.push_str(" -> ");
5018 err.push_str(&path.to_string_lossy());
5019 return Err(self.span_fatal(id_sp, &err[..]));
5023 included_mod_stack.push(path.clone());
5024 drop(included_mod_stack);
5026 let mut p0 = new_sub_parser_from_file(self.sess,
5032 let mod_inner_lo = p0.span.lo;
5033 let mod_attrs = p0.parse_inner_attributes();
5034 let m0 = try!(p0.parse_mod_items(&token::Eof, mod_inner_lo));
5035 self.sess.included_mod_stack.borrow_mut().pop();
5036 Ok((ast::ItemMod(m0), mod_attrs))
5039 /// Parse a function declaration from a foreign module
5040 fn parse_item_foreign_fn(&mut self, vis: ast::Visibility, lo: BytePos,
5041 attrs: Vec<Attribute>) -> PResult<P<ForeignItem>> {
5042 try!(self.expect_keyword(keywords::Fn));
5044 let (ident, mut generics) = try!(self.parse_fn_header());
5045 let decl = try!(self.parse_fn_decl(true));
5046 generics.where_clause = try!(self.parse_where_clause());
5047 let hi = self.span.hi;
5048 try!(self.expect(&token::Semi));
5049 Ok(P(ast::ForeignItem {
5052 node: ForeignItemFn(decl, generics),
5053 id: ast::DUMMY_NODE_ID,
5054 span: mk_sp(lo, hi),
5059 /// Parse a static item from a foreign module
5060 fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: BytePos,
5061 attrs: Vec<Attribute>) -> PResult<P<ForeignItem>> {
5062 try!(self.expect_keyword(keywords::Static));
5063 let mutbl = try!(self.eat_keyword(keywords::Mut));
5065 let ident = try!(self.parse_ident());
5066 try!(self.expect(&token::Colon));
5067 let ty = try!(self.parse_ty_sum());
5068 let hi = self.span.hi;
5069 try!(self.expect(&token::Semi));
5073 node: ForeignItemStatic(ty, mutbl),
5074 id: ast::DUMMY_NODE_ID,
5075 span: mk_sp(lo, hi),
5080 /// Parse extern crate links
5084 /// extern crate foo;
5085 /// extern crate bar as foo;
5086 fn parse_item_extern_crate(&mut self,
5088 visibility: Visibility,
5089 attrs: Vec<Attribute>)
5090 -> PResult<P<Item>> {
5092 let crate_name = try!(self.parse_ident());
5093 let (maybe_path, ident) = if let Some(ident) = try!(self.parse_rename()) {
5094 (Some(crate_name.name), ident)
5098 try!(self.expect(&token::Semi));
5100 let last_span = self.last_span;
5104 ItemExternCrate(maybe_path),
5109 /// Parse `extern` for foreign ABIs
5112 /// `extern` is expected to have been
5113 /// consumed before calling this method
5119 fn parse_item_foreign_mod(&mut self,
5121 opt_abi: Option<abi::Abi>,
5122 visibility: Visibility,
5123 mut attrs: Vec<Attribute>)
5124 -> PResult<P<Item>> {
5125 try!(self.expect(&token::OpenDelim(token::Brace)));
5127 let abi = opt_abi.unwrap_or(abi::C);
5129 attrs.extend(self.parse_inner_attributes());
5131 let mut foreign_items = vec![];
5132 while let Some(item) = try!(self.parse_foreign_item()) {
5133 foreign_items.push(item);
5135 try!(self.expect(&token::CloseDelim(token::Brace)));
5137 let last_span = self.last_span;
5138 let m = ast::ForeignMod {
5140 items: foreign_items
5144 special_idents::invalid,
5150 /// Parse type Foo = Bar;
5151 fn parse_item_type(&mut self) -> PResult<ItemInfo> {
5152 let ident = try!(self.parse_ident());
5153 let mut tps = try!(self.parse_generics());
5154 tps.where_clause = try!(self.parse_where_clause());
5155 try!(self.expect(&token::Eq));
5156 let ty = try!(self.parse_ty_sum());
5157 try!(self.expect(&token::Semi));
5158 Ok((ident, ItemTy(ty, tps), None))
5161 /// Parse a structure-like enum variant definition
5162 /// this should probably be renamed or refactored...
5163 fn parse_struct_def(&mut self) -> PResult<P<StructDef>> {
5164 let mut fields: Vec<StructField> = Vec::new();
5165 while self.token != token::CloseDelim(token::Brace) {
5166 fields.push(try!(self.parse_struct_decl_field(false)));
5176 /// Parse the part of an "enum" decl following the '{'
5177 fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<EnumDef> {
5178 let mut variants = Vec::new();
5179 let mut all_nullary = true;
5180 let mut any_disr = None;
5181 while self.token != token::CloseDelim(token::Brace) {
5182 let variant_attrs = self.parse_outer_attributes();
5183 let vlo = self.span.lo;
5185 let vis = try!(self.parse_visibility());
5189 let mut args = Vec::new();
5190 let mut disr_expr = None;
5191 ident = try!(self.parse_ident());
5192 if try!(self.eat(&token::OpenDelim(token::Brace)) ){
5193 // Parse a struct variant.
5194 all_nullary = false;
5195 let start_span = self.span;
5196 let struct_def = try!(self.parse_struct_def());
5197 if struct_def.fields.is_empty() {
5198 self.span_err(start_span,
5199 &format!("unit-like struct variant should be written \
5200 without braces, as `{},`",
5203 kind = StructVariantKind(struct_def);
5204 } else if self.check(&token::OpenDelim(token::Paren)) {
5205 all_nullary = false;
5206 let arg_tys = try!(self.parse_enum_variant_seq(
5207 &token::OpenDelim(token::Paren),
5208 &token::CloseDelim(token::Paren),
5209 seq_sep_trailing_allowed(token::Comma),
5210 |p| p.parse_ty_sum()
5213 args.push(ast::VariantArg {
5215 id: ast::DUMMY_NODE_ID,
5218 kind = TupleVariantKind(args);
5219 } else if try!(self.eat(&token::Eq) ){
5220 disr_expr = Some(try!(self.parse_expr_nopanic()));
5221 any_disr = disr_expr.as_ref().map(|expr| expr.span);
5222 kind = TupleVariantKind(args);
5224 kind = TupleVariantKind(Vec::new());
5227 let vr = ast::Variant_ {
5229 attrs: variant_attrs,
5231 id: ast::DUMMY_NODE_ID,
5232 disr_expr: disr_expr,
5235 variants.push(P(spanned(vlo, self.last_span.hi, vr)));
5237 if !try!(self.eat(&token::Comma)) { break; }
5239 try!(self.expect(&token::CloseDelim(token::Brace)));
5241 Some(disr_span) if !all_nullary =>
5242 self.span_err(disr_span,
5243 "discriminator values can only be used with a c-like enum"),
5247 Ok(ast::EnumDef { variants: variants })
5250 /// Parse an "enum" declaration
5251 fn parse_item_enum(&mut self) -> PResult<ItemInfo> {
5252 let id = try!(self.parse_ident());
5253 let mut generics = try!(self.parse_generics());
5254 generics.where_clause = try!(self.parse_where_clause());
5255 try!(self.expect(&token::OpenDelim(token::Brace)));
5257 let enum_definition = try!(self.parse_enum_def(&generics));
5258 Ok((id, ItemEnum(enum_definition, generics), None))
5261 /// Parses a string as an ABI spec on an extern type or module. Consumes
5262 /// the `extern` keyword, if one is found.
5263 fn parse_opt_abi(&mut self) -> PResult<Option<abi::Abi>> {
5265 token::Literal(token::Str_(s), suf) | token::Literal(token::StrRaw(s, _), suf) => {
5267 self.expect_no_suffix(sp, "ABI spec", suf);
5269 match abi::lookup(&s.as_str()) {
5270 Some(abi) => Ok(Some(abi)),
5272 let last_span = self.last_span;
5275 &format!("invalid ABI: expected one of [{}], \
5277 abi::all_names().join(", "),
5288 /// Parse one of the items allowed by the flags.
5289 /// NB: this function no longer parses the items inside an
5291 fn parse_item_(&mut self, attrs: Vec<Attribute>,
5292 macros_allowed: bool) -> PResult<Option<P<Item>>> {
5293 let nt_item = match self.token {
5294 token::Interpolated(token::NtItem(ref item)) => {
5295 Some((**item).clone())
5302 let mut attrs = attrs;
5303 mem::swap(&mut item.attrs, &mut attrs);
5304 item.attrs.extend(attrs);
5305 return Ok(Some(P(item)));
5310 let lo = self.span.lo;
5312 let visibility = try!(self.parse_visibility());
5314 if try!(self.eat_keyword(keywords::Use) ){
5316 let item_ = ItemUse(try!(self.parse_view_path()));
5317 try!(self.expect(&token::Semi));
5319 let last_span = self.last_span;
5320 let item = self.mk_item(lo,
5322 token::special_idents::invalid,
5326 return Ok(Some(item));
5329 if try!(self.eat_keyword(keywords::Extern)) {
5330 if try!(self.eat_keyword(keywords::Crate)) {
5331 return Ok(Some(try!(self.parse_item_extern_crate(lo, visibility, attrs))));
5334 let opt_abi = try!(self.parse_opt_abi());
5336 if try!(self.eat_keyword(keywords::Fn) ){
5337 // EXTERN FUNCTION ITEM
5338 let abi = opt_abi.unwrap_or(abi::C);
5339 let (ident, item_, extra_attrs) =
5340 try!(self.parse_item_fn(Unsafety::Normal, Constness::NotConst, abi));
5341 let last_span = self.last_span;
5342 let item = self.mk_item(lo,
5347 maybe_append(attrs, extra_attrs));
5348 return Ok(Some(item));
5349 } else if self.check(&token::OpenDelim(token::Brace)) {
5350 return Ok(Some(try!(self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs))));
5353 try!(self.expect_one_of(&[], &[]));
5356 if try!(self.eat_keyword(keywords::Static) ){
5358 let m = if try!(self.eat_keyword(keywords::Mut)) {MutMutable} else {MutImmutable};
5359 let (ident, item_, extra_attrs) = try!(self.parse_item_const(Some(m)));
5360 let last_span = self.last_span;
5361 let item = self.mk_item(lo,
5366 maybe_append(attrs, extra_attrs));
5367 return Ok(Some(item));
5369 if try!(self.eat_keyword(keywords::Const) ){
5370 if self.check_keyword(keywords::Fn) {
5371 // CONST FUNCTION ITEM
5373 let (ident, item_, extra_attrs) =
5374 try!(self.parse_item_fn(Unsafety::Normal, Constness::Const, abi::Rust));
5375 let last_span = self.last_span;
5376 let item = self.mk_item(lo,
5381 maybe_append(attrs, extra_attrs));
5382 return Ok(Some(item));
5386 if try!(self.eat_keyword(keywords::Mut) ){
5387 let last_span = self.last_span;
5388 self.span_err(last_span, "const globals cannot be mutable");
5389 self.fileline_help(last_span, "did you mean to declare a static?");
5391 let (ident, item_, extra_attrs) = try!(self.parse_item_const(None));
5392 let last_span = self.last_span;
5393 let item = self.mk_item(lo,
5398 maybe_append(attrs, extra_attrs));
5399 return Ok(Some(item));
5401 if self.check_keyword(keywords::Unsafe) &&
5402 self.look_ahead(1, |t| t.is_keyword(keywords::Trait))
5404 // UNSAFE TRAIT ITEM
5405 try!(self.expect_keyword(keywords::Unsafe));
5406 try!(self.expect_keyword(keywords::Trait));
5407 let (ident, item_, extra_attrs) =
5408 try!(self.parse_item_trait(ast::Unsafety::Unsafe));
5409 let last_span = self.last_span;
5410 let item = self.mk_item(lo,
5415 maybe_append(attrs, extra_attrs));
5416 return Ok(Some(item));
5418 if self.check_keyword(keywords::Unsafe) &&
5419 self.look_ahead(1, |t| t.is_keyword(keywords::Impl))
5422 try!(self.expect_keyword(keywords::Unsafe));
5423 try!(self.expect_keyword(keywords::Impl));
5424 let (ident, item_, extra_attrs) = try!(self.parse_item_impl(ast::Unsafety::Unsafe));
5425 let last_span = self.last_span;
5426 let item = self.mk_item(lo,
5431 maybe_append(attrs, extra_attrs));
5432 return Ok(Some(item));
5434 if self.check_keyword(keywords::Fn) {
5437 let (ident, item_, extra_attrs) =
5438 try!(self.parse_item_fn(Unsafety::Normal, Constness::NotConst, abi::Rust));
5439 let last_span = self.last_span;
5440 let item = self.mk_item(lo,
5445 maybe_append(attrs, extra_attrs));
5446 return Ok(Some(item));
5448 if self.check_keyword(keywords::Unsafe)
5449 && self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) {
5450 // UNSAFE FUNCTION ITEM
5452 let abi = if try!(self.eat_keyword(keywords::Extern) ){
5453 try!(self.parse_opt_abi()).unwrap_or(abi::C)
5457 try!(self.expect_keyword(keywords::Fn));
5458 let (ident, item_, extra_attrs) =
5459 try!(self.parse_item_fn(Unsafety::Unsafe, Constness::NotConst, abi));
5460 let last_span = self.last_span;
5461 let item = self.mk_item(lo,
5466 maybe_append(attrs, extra_attrs));
5467 return Ok(Some(item));
5469 if try!(self.eat_keyword(keywords::Mod) ){
5471 let (ident, item_, extra_attrs) =
5472 try!(self.parse_item_mod(&attrs[..]));
5473 let last_span = self.last_span;
5474 let item = self.mk_item(lo,
5479 maybe_append(attrs, extra_attrs));
5480 return Ok(Some(item));
5482 if try!(self.eat_keyword(keywords::Type) ){
5484 let (ident, item_, extra_attrs) = try!(self.parse_item_type());
5485 let last_span = self.last_span;
5486 let item = self.mk_item(lo,
5491 maybe_append(attrs, extra_attrs));
5492 return Ok(Some(item));
5494 if try!(self.eat_keyword(keywords::Enum) ){
5496 let (ident, item_, extra_attrs) = try!(self.parse_item_enum());
5497 let last_span = self.last_span;
5498 let item = self.mk_item(lo,
5503 maybe_append(attrs, extra_attrs));
5504 return Ok(Some(item));
5506 if try!(self.eat_keyword(keywords::Trait) ){
5508 let (ident, item_, extra_attrs) =
5509 try!(self.parse_item_trait(ast::Unsafety::Normal));
5510 let last_span = self.last_span;
5511 let item = self.mk_item(lo,
5516 maybe_append(attrs, extra_attrs));
5517 return Ok(Some(item));
5519 if try!(self.eat_keyword(keywords::Impl) ){
5521 let (ident, item_, extra_attrs) = try!(self.parse_item_impl(ast::Unsafety::Normal));
5522 let last_span = self.last_span;
5523 let item = self.mk_item(lo,
5528 maybe_append(attrs, extra_attrs));
5529 return Ok(Some(item));
5531 if try!(self.eat_keyword(keywords::Struct) ){
5533 let (ident, item_, extra_attrs) = try!(self.parse_item_struct());
5534 let last_span = self.last_span;
5535 let item = self.mk_item(lo,
5540 maybe_append(attrs, extra_attrs));
5541 return Ok(Some(item));
5543 self.parse_macro_use_or_failure(attrs,macros_allowed,lo,visibility)
5546 /// Parse a foreign item.
5547 fn parse_foreign_item(&mut self) -> PResult<Option<P<ForeignItem>>> {
5548 let attrs = self.parse_outer_attributes();
5549 let lo = self.span.lo;
5550 let visibility = try!(self.parse_visibility());
5552 if self.check_keyword(keywords::Static) {
5553 // FOREIGN STATIC ITEM
5554 return Ok(Some(try!(self.parse_item_foreign_static(visibility, lo, attrs))));
5556 if self.check_keyword(keywords::Fn) || self.check_keyword(keywords::Unsafe) {
5557 // FOREIGN FUNCTION ITEM
5558 return Ok(Some(try!(self.parse_item_foreign_fn(visibility, lo, attrs))));
5561 // FIXME #5668: this will occur for a macro invocation:
5562 match try!(self.parse_macro_use_or_failure(attrs, true, lo, visibility)) {
5564 return Err(self.span_fatal(item.span, "macros cannot expand to foreign items"));
5570 /// This is the fall-through for parsing items.
5571 fn parse_macro_use_or_failure(
5573 attrs: Vec<Attribute> ,
5574 macros_allowed: bool,
5576 visibility: Visibility
5577 ) -> PResult<Option<P<Item>>> {
5578 if macros_allowed && !self.token.is_any_keyword()
5579 && self.look_ahead(1, |t| *t == token::Not)
5580 && (self.look_ahead(2, |t| t.is_plain_ident())
5581 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Paren))
5582 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))) {
5583 // MACRO INVOCATION ITEM
5585 let last_span = self.last_span;
5586 self.complain_if_pub_macro(visibility, last_span);
5589 let pth = try!(self.parse_path(NoTypesAllowed));
5590 try!(self.expect(&token::Not));
5592 // a 'special' identifier (like what `macro_rules!` uses)
5593 // is optional. We should eventually unify invoc syntax
5595 let id = if self.token.is_plain_ident() {
5596 try!(self.parse_ident())
5598 token::special_idents::invalid // no special identifier
5600 // eat a matched-delimiter token tree:
5601 let delim = try!(self.expect_open_delim());
5602 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
5604 |p| p.parse_token_tree()));
5605 // single-variant-enum... :
5606 let m = ast::MacInvocTT(pth, tts, EMPTY_CTXT);
5607 let m: ast::Mac = codemap::Spanned { node: m,
5608 span: mk_sp(self.span.lo,
5611 if delim != token::Brace {
5612 if !try!(self.eat(&token::Semi) ){
5613 let last_span = self.last_span;
5614 self.span_err(last_span,
5615 "macros that expand to items must either \
5616 be surrounded with braces or followed by \
5621 let item_ = ItemMac(m);
5622 let last_span = self.last_span;
5623 let item = self.mk_item(lo,
5629 return Ok(Some(item));
5632 // FAILURE TO PARSE ITEM
5636 let last_span = self.last_span;
5637 return Err(self.span_fatal(last_span, "unmatched visibility `pub`"));
5641 if !attrs.is_empty() {
5642 self.expected_item_err(&attrs);
5647 pub fn parse_item_nopanic(&mut self) -> PResult<Option<P<Item>>> {
5648 let attrs = self.parse_outer_attributes();
5649 self.parse_item_(attrs, true)
5653 /// Matches view_path : MOD? non_global_path as IDENT
5654 /// | MOD? non_global_path MOD_SEP LBRACE RBRACE
5655 /// | MOD? non_global_path MOD_SEP LBRACE ident_seq RBRACE
5656 /// | MOD? non_global_path MOD_SEP STAR
5657 /// | MOD? non_global_path
5658 fn parse_view_path(&mut self) -> PResult<P<ViewPath>> {
5659 let lo = self.span.lo;
5661 // Allow a leading :: because the paths are absolute either way.
5662 // This occurs with "use $crate::..." in macros.
5663 try!(self.eat(&token::ModSep));
5665 if self.check(&token::OpenDelim(token::Brace)) {
5667 let idents = try!(self.parse_unspanned_seq(
5668 &token::OpenDelim(token::Brace),
5669 &token::CloseDelim(token::Brace),
5670 seq_sep_trailing_allowed(token::Comma),
5671 |p| p.parse_path_list_item()));
5672 let path = ast::Path {
5673 span: mk_sp(lo, self.span.hi),
5675 segments: Vec::new()
5677 return Ok(P(spanned(lo, self.span.hi, ViewPathList(path, idents))));
5680 let first_ident = try!(self.parse_ident());
5681 let mut path = vec!(first_ident);
5682 if let token::ModSep = self.token {
5683 // foo::bar or foo::{a,b,c} or foo::*
5684 while self.check(&token::ModSep) {
5688 token::Ident(..) => {
5689 let ident = try!(self.parse_ident());
5693 // foo::bar::{a,b,c}
5694 token::OpenDelim(token::Brace) => {
5695 let idents = try!(self.parse_unspanned_seq(
5696 &token::OpenDelim(token::Brace),
5697 &token::CloseDelim(token::Brace),
5698 seq_sep_trailing_allowed(token::Comma),
5699 |p| p.parse_path_list_item()
5701 let path = ast::Path {
5702 span: mk_sp(lo, self.span.hi),
5704 segments: path.into_iter().map(|identifier| {
5706 identifier: identifier,
5707 parameters: ast::PathParameters::none(),
5711 return Ok(P(spanned(lo, self.span.hi, ViewPathList(path, idents))));
5715 token::BinOp(token::Star) => {
5717 let path = ast::Path {
5718 span: mk_sp(lo, self.span.hi),
5720 segments: path.into_iter().map(|identifier| {
5722 identifier: identifier,
5723 parameters: ast::PathParameters::none(),
5727 return Ok(P(spanned(lo, self.span.hi, ViewPathGlob(path))));
5730 // fall-through for case foo::bar::;
5732 self.span_err(self.span, "expected identifier or `{` or `*`, found `;`");
5739 let mut rename_to = path[path.len() - 1];
5740 let path = ast::Path {
5741 span: mk_sp(lo, self.last_span.hi),
5743 segments: path.into_iter().map(|identifier| {
5745 identifier: identifier,
5746 parameters: ast::PathParameters::none(),
5750 rename_to = try!(self.parse_rename()).unwrap_or(rename_to);
5751 Ok(P(spanned(lo, self.last_span.hi, ViewPathSimple(rename_to, path))))
5754 fn parse_rename(&mut self) -> PResult<Option<Ident>> {
5755 if try!(self.eat_keyword(keywords::As)) {
5756 self.parse_ident().map(Some)
5762 /// Parses a source module as a crate. This is the main
5763 /// entry point for the parser.
5764 pub fn parse_crate_mod(&mut self) -> PResult<Crate> {
5765 let lo = self.span.lo;
5767 attrs: self.parse_inner_attributes(),
5768 module: try!(self.parse_mod_items(&token::Eof, lo)),
5769 config: self.cfg.clone(),
5770 span: mk_sp(lo, self.span.lo),
5771 exported_macros: Vec::new(),
5775 pub fn parse_optional_str(&mut self)
5776 -> PResult<Option<(InternedString,
5778 Option<ast::Name>)>> {
5779 let ret = match self.token {
5780 token::Literal(token::Str_(s), suf) => {
5781 (self.id_to_interned_str(s.ident()), ast::CookedStr, suf)
5783 token::Literal(token::StrRaw(s, n), suf) => {
5784 (self.id_to_interned_str(s.ident()), ast::RawStr(n), suf)
5786 _ => return Ok(None)
5792 pub fn parse_str(&mut self) -> PResult<(InternedString, StrStyle)> {
5793 match try!(self.parse_optional_str()) {
5794 Some((s, style, suf)) => {
5795 let sp = self.last_span;
5796 self.expect_no_suffix(sp, "string literal", suf);
5799 _ => Err(self.fatal("expected string literal"))