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, BindingMode};
18 use ast::{BiBitAnd, BiBitOr, BiBitXor, BiRem, BiLt, Block};
19 use ast::{BlockCheckMode, CaptureByRef, CaptureByValue, CaptureClause};
20 use ast::{Constness, 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, ExprInPlace};
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, ExprType, ExprUnary};
30 use ast::{ExprVec, ExprWhile, ExprWhileLet, ExprForLoop, Field, FnDecl};
31 use ast::{ForeignItem, ForeignItemStatic, ForeignItemFn, 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};
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_};
41 use ast::{MutTy, BiMul, Mutability};
42 use ast::{NamedField, UnNeg, NoReturn, UnNot};
43 use ast::{Pat, PatBox, PatEnum, PatIdent, PatLit, PatQPath, PatMac, PatRange};
44 use ast::{PatRegion, PatStruct, PatTup, PatVec, PatWild};
45 use ast::{PolyTraitRef, QSelf};
46 use ast::{Return, BiShl, BiShr, Stmt, StmtDecl};
47 use ast::{StmtExpr, StmtSemi, StmtMac, VariantData, StructField};
48 use ast::{BiSub, StrStyle};
49 use ast::{SelfExplicit, SelfRegion, SelfStatic, SelfValue};
50 use ast::{Delimited, SequenceRepetition, TokenTree, TraitItem, TraitRef};
51 use ast::{Ty, Ty_, TypeBinding, TyMac};
52 use ast::{TyFixedLengthVec, TyBareFn, TyTypeof, TyInfer};
53 use ast::{TyParam, TyParamBounds, TyParen, TyPath, TyPtr};
54 use ast::{TyRptr, TyTup, TyU32, TyVec};
55 use ast::TypeTraitItem;
56 use ast::{UnnamedField, UnsafeBlock};
57 use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
58 use ast::{Visibility, WhereClause};
59 use attr::{ThinAttributes, ThinAttributesExt, AttributesExt};
61 use ast_util::{self, ident_to_path};
62 use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp, CodeMap};
63 use errors::{self, DiagnosticBuilder};
64 use ext::tt::macro_parser;
67 use parse::common::{SeqSep, seq_sep_none, seq_sep_trailing_allowed};
68 use parse::lexer::{Reader, TokenAndSpan};
69 use parse::obsolete::{ParserObsoleteMethods, ObsoleteSyntax};
70 use parse::token::{self, MatchNt, SubstNt, SpecialVarNt, InternedString};
71 use parse::token::{keywords, special_idents, SpecialMacroVar};
72 use parse::{new_sub_parser_from_file, ParseSess};
73 use util::parser::{AssocOp, Fixity};
78 use std::collections::HashSet;
79 use std::io::prelude::*;
81 use std::path::{Path, PathBuf};
86 flags Restrictions: u8 {
87 const RESTRICTION_STMT_EXPR = 1 << 0,
88 const RESTRICTION_NO_STRUCT_LITERAL = 1 << 1,
92 type ItemInfo = (Ident, Item_, Option<Vec<Attribute> >);
94 /// How to parse a path. There are four different kinds of paths, all of which
95 /// are parsed somewhat differently.
96 #[derive(Copy, Clone, PartialEq)]
97 pub enum PathParsingMode {
98 /// A path with no type parameters; e.g. `foo::bar::Baz`
100 /// A path with a lifetime and type parameters, with no double colons
101 /// before the type parameters; e.g. `foo::bar<'a>::Baz<T>`
102 LifetimeAndTypesWithoutColons,
103 /// A path with a lifetime and type parameters with double colons before
104 /// the type parameters; e.g. `foo::bar::<'a>::Baz::<T>`
105 LifetimeAndTypesWithColons,
108 /// How to parse a bound, whether to allow bound modifiers such as `?`.
109 #[derive(Copy, Clone, PartialEq)]
110 pub enum BoundParsingMode {
115 /// `pub` should be parsed in struct fields and not parsed in variant fields
116 #[derive(Clone, Copy, PartialEq)]
122 /// Possibly accept an `token::Interpolated` expression (a pre-parsed expression
123 /// dropped into the token stream, which happens while parsing the result of
124 /// macro expansion). Placement of these is not as complex as I feared it would
125 /// be. The important thing is to make sure that lookahead doesn't balk at
126 /// `token::Interpolated` tokens.
127 macro_rules! maybe_whole_expr {
130 let found = match $p.token {
131 token::Interpolated(token::NtExpr(ref e)) => {
134 token::Interpolated(token::NtPath(_)) => {
135 // FIXME: The following avoids an issue with lexical borrowck scopes,
136 // but the clone is unfortunate.
137 let pt = match $p.token {
138 token::Interpolated(token::NtPath(ref pt)) => (**pt).clone(),
142 Some($p.mk_expr(span.lo, span.hi, ExprPath(None, pt), None))
144 token::Interpolated(token::NtBlock(_)) => {
145 // FIXME: The following avoids an issue with lexical borrowck scopes,
146 // but the clone is unfortunate.
147 let b = match $p.token {
148 token::Interpolated(token::NtBlock(ref b)) => (*b).clone(),
152 Some($p.mk_expr(span.lo, span.hi, ExprBlock(b), None))
167 /// As maybe_whole_expr, but for things other than expressions
168 macro_rules! maybe_whole {
169 ($p:expr, $constructor:ident) => (
171 let found = match ($p).token {
172 token::Interpolated(token::$constructor(_)) => {
173 Some(try!(($p).bump_and_get()))
177 if let Some(token::Interpolated(token::$constructor(x))) = found {
178 return Ok(x.clone());
182 (no_clone $p:expr, $constructor:ident) => (
184 let found = match ($p).token {
185 token::Interpolated(token::$constructor(_)) => {
186 Some(try!(($p).bump_and_get()))
190 if let Some(token::Interpolated(token::$constructor(x))) = found {
195 (deref $p:expr, $constructor:ident) => (
197 let found = match ($p).token {
198 token::Interpolated(token::$constructor(_)) => {
199 Some(try!(($p).bump_and_get()))
203 if let Some(token::Interpolated(token::$constructor(x))) = found {
204 return Ok((*x).clone());
208 (Some deref $p:expr, $constructor:ident) => (
210 let found = match ($p).token {
211 token::Interpolated(token::$constructor(_)) => {
212 Some(try!(($p).bump_and_get()))
216 if let Some(token::Interpolated(token::$constructor(x))) = found {
217 return Ok(Some((*x).clone()));
221 (pair_empty $p:expr, $constructor:ident) => (
223 let found = match ($p).token {
224 token::Interpolated(token::$constructor(_)) => {
225 Some(try!(($p).bump_and_get()))
229 if let Some(token::Interpolated(token::$constructor(x))) = found {
230 return Ok((Vec::new(), x));
237 fn maybe_append(mut lhs: Vec<Attribute>, rhs: Option<Vec<Attribute>>)
239 if let Some(ref attrs) = rhs {
240 lhs.extend(attrs.iter().cloned())
245 /* ident is handled by common.rs */
247 pub struct Parser<'a> {
248 pub sess: &'a ParseSess,
249 /// the current token:
250 pub token: token::Token,
251 /// the span of the current token:
253 /// the span of the prior token:
255 pub cfg: CrateConfig,
256 /// the previous token or None (only stashed sometimes).
257 pub last_token: Option<Box<token::Token>>,
258 pub buffer: [TokenAndSpan; 4],
259 pub buffer_start: isize,
260 pub buffer_end: isize,
261 pub tokens_consumed: usize,
262 pub restrictions: Restrictions,
263 pub quote_depth: usize, // not (yet) related to the quasiquoter
264 pub reader: Box<Reader+'a>,
265 pub interner: Rc<token::IdentInterner>,
266 /// The set of seen errors about obsolete syntax. Used to suppress
267 /// extra detail when the same error is seen twice
268 pub obsolete_set: HashSet<ObsoleteSyntax>,
269 /// Used to determine the path to externally loaded source files
270 pub mod_path_stack: Vec<InternedString>,
271 /// Stack of spans of open delimiters. Used for error message.
272 pub open_braces: Vec<Span>,
273 /// Flag if this parser "owns" the directory that it is currently parsing
274 /// in. This will affect how nested files are looked up.
275 pub owns_directory: bool,
276 /// Name of the root module this parser originated from. If `None`, then the
277 /// name is not known. This does not change while the parser is descending
278 /// into modules, and sub-parsers have new values for this name.
279 pub root_module_name: Option<String>,
280 pub expected_tokens: Vec<TokenType>,
283 #[derive(PartialEq, Eq, Clone)]
286 Keyword(keywords::Keyword),
291 fn to_string(&self) -> String {
293 TokenType::Token(ref t) => format!("`{}`", Parser::token_to_string(t)),
294 TokenType::Operator => "an operator".to_string(),
295 TokenType::Keyword(kw) => format!("`{}`", kw.to_name()),
300 fn is_plain_ident_or_underscore(t: &token::Token) -> bool {
301 t.is_plain_ident() || *t == token::Underscore
304 /// Information about the path to a module.
305 pub struct ModulePath {
307 pub path_exists: bool,
308 pub result: Result<ModulePathSuccess, ModulePathError>,
311 pub struct ModulePathSuccess {
312 pub path: ::std::path::PathBuf,
313 pub owns_directory: bool,
316 pub struct ModulePathError {
318 pub help_msg: String,
323 AttributesParsed(ThinAttributes),
324 AlreadyParsed(P<Expr>),
327 impl From<Option<ThinAttributes>> for LhsExpr {
328 fn from(o: Option<ThinAttributes>) -> Self {
329 if let Some(attrs) = o {
330 LhsExpr::AttributesParsed(attrs)
332 LhsExpr::NotYetParsed
337 impl From<P<Expr>> for LhsExpr {
338 fn from(expr: P<Expr>) -> Self {
339 LhsExpr::AlreadyParsed(expr)
343 impl<'a> Parser<'a> {
344 pub fn new(sess: &'a ParseSess,
345 cfg: ast::CrateConfig,
346 mut rdr: Box<Reader+'a>)
349 let tok0 = rdr.real_token();
351 let placeholder = TokenAndSpan {
352 tok: token::Underscore,
358 interner: token::get_ident_interner(),
374 restrictions: Restrictions::empty(),
376 obsolete_set: HashSet::new(),
377 mod_path_stack: Vec::new(),
378 open_braces: Vec::new(),
379 owns_directory: true,
380 root_module_name: None,
381 expected_tokens: Vec::new(),
385 /// Convert a token to a string using self's reader
386 pub fn token_to_string(token: &token::Token) -> String {
387 pprust::token_to_string(token)
390 /// Convert the current token to a string using self's reader
391 pub fn this_token_to_string(&self) -> String {
392 Parser::token_to_string(&self.token)
395 pub fn unexpected_last(&self, t: &token::Token) -> DiagnosticBuilder<'a> {
396 let token_str = Parser::token_to_string(t);
397 let last_span = self.last_span;
398 self.span_fatal(last_span, &format!("unexpected token: `{}`",
402 pub fn unexpected(&mut self) -> DiagnosticBuilder<'a> {
403 match self.expect_one_of(&[], &[]) {
405 Ok(_) => unreachable!()
409 /// Expect and consume the token t. Signal an error if
410 /// the next token is not t.
411 pub fn expect(&mut self, t: &token::Token) -> PResult<'a, ()> {
412 if self.expected_tokens.is_empty() {
413 if self.token == *t {
416 let token_str = Parser::token_to_string(t);
417 let this_token_str = self.this_token_to_string();
418 Err(self.fatal(&format!("expected `{}`, found `{}`",
423 self.expect_one_of(unsafe { slice::from_raw_parts(t, 1) }, &[])
427 /// Expect next token to be edible or inedible token. If edible,
428 /// then consume it; if inedible, then return without consuming
429 /// anything. Signal a fatal error if next token is unexpected.
430 pub fn expect_one_of(&mut self,
431 edible: &[token::Token],
432 inedible: &[token::Token]) -> PResult<'a, ()>{
433 fn tokens_to_string(tokens: &[TokenType]) -> String {
434 let mut i = tokens.iter();
435 // This might be a sign we need a connect method on Iterator.
437 .map_or("".to_string(), |t| t.to_string());
438 i.enumerate().fold(b, |mut b, (i, ref a)| {
439 if tokens.len() > 2 && i == tokens.len() - 2 {
441 } else if tokens.len() == 2 && i == tokens.len() - 2 {
446 b.push_str(&*a.to_string());
450 if edible.contains(&self.token) {
452 } else if inedible.contains(&self.token) {
453 // leave it in the input
456 let mut expected = edible.iter()
457 .map(|x| TokenType::Token(x.clone()))
458 .chain(inedible.iter().map(|x| TokenType::Token(x.clone())))
459 .chain(self.expected_tokens.iter().cloned())
460 .collect::<Vec<_>>();
461 expected.sort_by(|a, b| a.to_string().cmp(&b.to_string()));
463 let expect = tokens_to_string(&expected[..]);
464 let actual = self.this_token_to_string();
466 &(if expected.len() > 1 {
467 (format!("expected one of {}, found `{}`",
470 } else if expected.is_empty() {
471 (format!("unexpected token: `{}`",
474 (format!("expected {}, found `{}`",
482 /// Check for erroneous `ident { }`; if matches, signal error and
483 /// recover (without consuming any expected input token). Returns
484 /// true if and only if input was consumed for recovery.
485 pub fn check_for_erroneous_unit_struct_expecting(&mut self,
486 expected: &[token::Token])
487 -> PResult<'a, bool> {
488 if self.token == token::OpenDelim(token::Brace)
489 && expected.iter().all(|t| *t != token::OpenDelim(token::Brace))
490 && self.look_ahead(1, |t| *t == token::CloseDelim(token::Brace)) {
491 // matched; signal non-fatal error and recover.
492 let span = self.span;
494 "unit-like struct construction is written with no trailing `{ }`");
495 try!(self.eat(&token::OpenDelim(token::Brace)));
496 try!(self.eat(&token::CloseDelim(token::Brace)));
503 /// Commit to parsing a complete expression `e` expected to be
504 /// followed by some token from the set edible + inedible. Recover
505 /// from anticipated input errors, discarding erroneous characters.
506 pub fn commit_expr(&mut self, e: &Expr, edible: &[token::Token],
507 inedible: &[token::Token]) -> PResult<'a, ()> {
508 debug!("commit_expr {:?}", e);
509 if let ExprPath(..) = e.node {
510 // might be unit-struct construction; check for recoverableinput error.
511 let expected = edible.iter()
513 .chain(inedible.iter().cloned())
514 .collect::<Vec<_>>();
515 try!(self.check_for_erroneous_unit_struct_expecting(&expected[..]));
517 self.expect_one_of(edible, inedible)
520 pub fn commit_expr_expecting(&mut self, e: &Expr, edible: token::Token) -> PResult<'a, ()> {
521 self.commit_expr(e, &[edible], &[])
524 /// Commit to parsing a complete statement `s`, which expects to be
525 /// followed by some token from the set edible + inedible. Check
526 /// for recoverable input errors, discarding erroneous characters.
527 pub fn commit_stmt(&mut self, edible: &[token::Token],
528 inedible: &[token::Token]) -> PResult<'a, ()> {
531 .map_or(false, |t| t.is_ident() || t.is_path()) {
532 let expected = edible.iter()
534 .chain(inedible.iter().cloned())
535 .collect::<Vec<_>>();
536 try!(self.check_for_erroneous_unit_struct_expecting(&expected));
538 self.expect_one_of(edible, inedible)
541 pub fn commit_stmt_expecting(&mut self, edible: token::Token) -> PResult<'a, ()> {
542 self.commit_stmt(&[edible], &[])
545 pub fn parse_ident(&mut self) -> PResult<'a, ast::Ident> {
546 self.check_strict_keywords();
547 try!(self.check_reserved_keywords());
549 token::Ident(i, _) => {
553 token::Interpolated(token::NtIdent(..)) => {
554 self.bug("ident interpolation not converted to real token");
557 let token_str = self.this_token_to_string();
558 Err(self.fatal(&format!("expected ident, found `{}`",
564 pub fn parse_ident_or_self_type(&mut self) -> PResult<'a, ast::Ident> {
565 if self.is_self_type_ident() {
566 self.expect_self_type_ident()
572 pub fn parse_path_list_item(&mut self) -> PResult<'a, ast::PathListItem> {
573 let lo = self.span.lo;
574 let node = if try!(self.eat_keyword(keywords::SelfValue)) {
575 let rename = try!(self.parse_rename());
576 ast::PathListMod { id: ast::DUMMY_NODE_ID, rename: rename }
578 let ident = try!(self.parse_ident());
579 let rename = try!(self.parse_rename());
580 ast::PathListIdent { name: ident, rename: rename, id: ast::DUMMY_NODE_ID }
582 let hi = self.last_span.hi;
583 Ok(spanned(lo, hi, node))
586 /// Check if the next token is `tok`, and return `true` if so.
588 /// This method is will automatically add `tok` to `expected_tokens` if `tok` is not
590 pub fn check(&mut self, tok: &token::Token) -> bool {
591 let is_present = self.token == *tok;
592 if !is_present { self.expected_tokens.push(TokenType::Token(tok.clone())); }
596 /// Consume token 'tok' if it exists. Returns true if the given
597 /// token was present, false otherwise.
598 pub fn eat(&mut self, tok: &token::Token) -> PResult<'a, bool> {
599 let is_present = self.check(tok);
600 if is_present { try!(self.bump())}
604 pub fn check_keyword(&mut self, kw: keywords::Keyword) -> bool {
605 self.expected_tokens.push(TokenType::Keyword(kw));
606 self.token.is_keyword(kw)
609 /// If the next token is the given keyword, eat it and return
610 /// true. Otherwise, return false.
611 pub fn eat_keyword(&mut self, kw: keywords::Keyword) -> PResult<'a, bool> {
612 if self.check_keyword(kw) {
620 pub fn eat_keyword_noexpect(&mut self, kw: keywords::Keyword) -> PResult<'a, bool> {
621 if self.token.is_keyword(kw) {
629 /// If the given word is not a keyword, signal an error.
630 /// If the next token is not the given word, signal an error.
631 /// Otherwise, eat it.
632 pub fn expect_keyword(&mut self, kw: keywords::Keyword) -> PResult<'a, ()> {
633 if !try!(self.eat_keyword(kw) ){
634 self.expect_one_of(&[], &[])
640 /// Signal an error if the given string is a strict keyword
641 pub fn check_strict_keywords(&mut self) {
642 if self.token.is_strict_keyword() {
643 let token_str = self.this_token_to_string();
644 let span = self.span;
646 &format!("expected identifier, found keyword `{}`",
651 /// Signal an error if the current token is a reserved keyword
652 pub fn check_reserved_keywords(&mut self) -> PResult<'a, ()>{
653 if self.token.is_reserved_keyword() {
654 let token_str = self.this_token_to_string();
655 Err(self.fatal(&format!("`{}` is a reserved keyword", token_str)))
661 /// Expect and consume an `&`. If `&&` is seen, replace it with a single
662 /// `&` and continue. If an `&` is not seen, signal an error.
663 fn expect_and(&mut self) -> PResult<'a, ()> {
664 self.expected_tokens.push(TokenType::Token(token::BinOp(token::And)));
666 token::BinOp(token::And) => self.bump(),
668 let span = self.span;
669 let lo = span.lo + BytePos(1);
670 Ok(self.replace_token(token::BinOp(token::And), lo, span.hi))
672 _ => self.expect_one_of(&[], &[])
676 pub fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<ast::Name>) {
678 None => {/* everything ok */}
680 let text = suf.as_str();
682 self.span_bug(sp, "found empty literal suffix in Some")
684 self.span_err(sp, &*format!("{} with a suffix is invalid", kind));
690 /// Attempt to consume a `<`. If `<<` is seen, replace it with a single
691 /// `<` and continue. If a `<` is not seen, return false.
693 /// This is meant to be used when parsing generics on a path to get the
695 fn eat_lt(&mut self) -> PResult<'a, bool> {
696 self.expected_tokens.push(TokenType::Token(token::Lt));
698 token::Lt => { try!(self.bump()); Ok(true)}
699 token::BinOp(token::Shl) => {
700 let span = self.span;
701 let lo = span.lo + BytePos(1);
702 self.replace_token(token::Lt, lo, span.hi);
709 fn expect_lt(&mut self) -> PResult<'a, ()> {
710 if !try!(self.eat_lt()) {
711 self.expect_one_of(&[], &[])
717 /// Expect and consume a GT. if a >> is seen, replace it
718 /// with a single > and continue. If a GT is not seen,
720 pub fn expect_gt(&mut self) -> PResult<'a, ()> {
721 self.expected_tokens.push(TokenType::Token(token::Gt));
723 token::Gt => self.bump(),
724 token::BinOp(token::Shr) => {
725 let span = self.span;
726 let lo = span.lo + BytePos(1);
727 Ok(self.replace_token(token::Gt, lo, span.hi))
729 token::BinOpEq(token::Shr) => {
730 let span = self.span;
731 let lo = span.lo + BytePos(1);
732 Ok(self.replace_token(token::Ge, lo, span.hi))
735 let span = self.span;
736 let lo = span.lo + BytePos(1);
737 Ok(self.replace_token(token::Eq, lo, span.hi))
740 let gt_str = Parser::token_to_string(&token::Gt);
741 let this_token_str = self.this_token_to_string();
742 Err(self.fatal(&format!("expected `{}`, found `{}`",
749 pub fn parse_seq_to_before_gt_or_return<T, F>(&mut self,
750 sep: Option<token::Token>,
752 -> PResult<'a, (P<[T]>, bool)> where
753 where F: FnMut(&mut Parser<'a>) -> PResult<'a, Option<T>>,
755 let mut v = Vec::new();
756 // This loop works by alternating back and forth between parsing types
757 // and commas. For example, given a string `A, B,>`, the parser would
758 // first parse `A`, then a comma, then `B`, then a comma. After that it
759 // would encounter a `>` and stop. This lets the parser handle trailing
760 // commas in generic parameters, because it can stop either after
761 // parsing a type or after parsing a comma.
763 if self.check(&token::Gt)
764 || self.token == token::BinOp(token::Shr)
765 || self.token == token::Ge
766 || self.token == token::BinOpEq(token::Shr) {
771 match try!(f(self)) {
772 Some(result) => v.push(result),
773 None => return Ok((P::from_vec(v), true))
776 if let Some(t) = sep.as_ref() {
777 try!(self.expect(t));
782 return Ok((P::from_vec(v), false));
785 /// Parse a sequence bracketed by '<' and '>', stopping
787 pub fn parse_seq_to_before_gt<T, F>(&mut self,
788 sep: Option<token::Token>,
790 -> PResult<'a, P<[T]>> where
791 F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
793 let (result, returned) = try!(self.parse_seq_to_before_gt_or_return(sep,
794 |p| Ok(Some(try!(f(p))))));
799 pub fn parse_seq_to_gt<T, F>(&mut self,
800 sep: Option<token::Token>,
802 -> PResult<'a, P<[T]>> where
803 F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
805 let v = try!(self.parse_seq_to_before_gt(sep, f));
806 try!(self.expect_gt());
810 pub fn parse_seq_to_gt_or_return<T, F>(&mut self,
811 sep: Option<token::Token>,
813 -> PResult<'a, (P<[T]>, bool)> where
814 F: FnMut(&mut Parser<'a>) -> PResult<'a, Option<T>>,
816 let (v, returned) = try!(self.parse_seq_to_before_gt_or_return(sep, f));
818 try!(self.expect_gt());
820 return Ok((v, returned));
823 /// Parse a sequence, including the closing delimiter. The function
824 /// f must consume tokens until reaching the next separator or
826 pub fn parse_seq_to_end<T, F>(&mut self,
830 -> PResult<'a, Vec<T>> where
831 F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
833 let val = try!(self.parse_seq_to_before_end(ket, sep, f));
838 /// Parse a sequence, not including the closing delimiter. The function
839 /// f must consume tokens until reaching the next separator or
841 pub fn parse_seq_to_before_end<T, F>(&mut self,
845 -> PResult<'a, Vec<T>> where
846 F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
848 let mut first: bool = true;
850 while self.token != *ket {
853 if first { first = false; }
854 else { try!(self.expect(t)); }
858 if sep.trailing_sep_allowed && self.check(ket) { break; }
859 v.push(try!(f(self)));
864 /// Parse a sequence, including the closing delimiter. The function
865 /// f must consume tokens until reaching the next separator or
867 pub fn parse_unspanned_seq<T, F>(&mut self,
872 -> PResult<'a, Vec<T>> where
873 F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
875 try!(self.expect(bra));
876 let result = try!(self.parse_seq_to_before_end(ket, sep, f));
881 /// Parse a sequence parameter of enum variant. For consistency purposes,
882 /// these should not be empty.
883 pub fn parse_enum_variant_seq<T, F>(&mut self,
888 -> PResult<'a, Vec<T>> where
889 F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
891 let result = try!(self.parse_unspanned_seq(bra, ket, sep, f));
892 if result.is_empty() {
893 let last_span = self.last_span;
894 self.span_err(last_span,
895 "nullary enum variants are written with no trailing `( )`");
900 // NB: Do not use this function unless you actually plan to place the
901 // spanned list in the AST.
902 pub fn parse_seq<T, F>(&mut self,
907 -> PResult<'a, Spanned<Vec<T>>> where
908 F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
910 let lo = self.span.lo;
911 try!(self.expect(bra));
912 let result = try!(self.parse_seq_to_before_end(ket, sep, f));
913 let hi = self.span.hi;
915 Ok(spanned(lo, hi, result))
918 /// Advance the parser by one token
919 pub fn bump(&mut self) -> PResult<'a, ()> {
920 self.last_span = self.span;
921 // Stash token for error recovery (sometimes; clone is not necessarily cheap).
922 self.last_token = if self.token.is_ident() ||
923 self.token.is_path() ||
924 self.token == token::Comma {
925 Some(Box::new(self.token.clone()))
929 let next = if self.buffer_start == self.buffer_end {
930 self.reader.real_token()
932 // Avoid token copies with `replace`.
933 let buffer_start = self.buffer_start as usize;
934 let next_index = (buffer_start + 1) & 3;
935 self.buffer_start = next_index as isize;
937 let placeholder = TokenAndSpan {
938 tok: token::Underscore,
941 mem::replace(&mut self.buffer[buffer_start], placeholder)
944 self.token = next.tok;
945 self.tokens_consumed += 1;
946 self.expected_tokens.clear();
947 // check after each token
948 self.check_unknown_macro_variable()
951 /// Advance the parser by one token and return the bumped token.
952 pub fn bump_and_get(&mut self) -> PResult<'a, token::Token> {
953 let old_token = mem::replace(&mut self.token, token::Underscore);
958 /// EFFECT: replace the current token and span with the given one
959 pub fn replace_token(&mut self,
963 self.last_span = mk_sp(self.span.lo, lo);
965 self.span = mk_sp(lo, hi);
967 pub fn buffer_length(&mut self) -> isize {
968 if self.buffer_start <= self.buffer_end {
969 return self.buffer_end - self.buffer_start;
971 return (4 - self.buffer_start) + self.buffer_end;
973 pub fn look_ahead<R, F>(&mut self, distance: usize, f: F) -> R where
974 F: FnOnce(&token::Token) -> R,
976 let dist = distance as isize;
977 while self.buffer_length() < dist {
978 self.buffer[self.buffer_end as usize] = self.reader.real_token();
979 self.buffer_end = (self.buffer_end + 1) & 3;
981 f(&self.buffer[((self.buffer_start + dist - 1) & 3) as usize].tok)
983 pub fn fatal(&self, m: &str) -> DiagnosticBuilder<'a> {
984 self.sess.span_diagnostic.struct_span_fatal(self.span, m)
986 pub fn span_fatal(&self, sp: Span, m: &str) -> DiagnosticBuilder<'a> {
987 self.sess.span_diagnostic.struct_span_fatal(sp, m)
989 pub fn span_fatal_help(&self, sp: Span, m: &str, help: &str) -> DiagnosticBuilder<'a> {
990 let mut err = self.sess.span_diagnostic.struct_span_fatal(sp, m);
991 err.fileline_help(sp, help);
994 pub fn bug(&self, m: &str) -> ! {
995 self.sess.span_diagnostic.span_bug(self.span, m)
997 pub fn warn(&self, m: &str) {
998 self.sess.span_diagnostic.span_warn(self.span, m)
1000 pub fn span_warn(&self, sp: Span, m: &str) {
1001 self.sess.span_diagnostic.span_warn(sp, m)
1003 pub fn span_err(&self, sp: Span, m: &str) {
1004 self.sess.span_diagnostic.span_err(sp, m)
1006 pub fn span_bug(&self, sp: Span, m: &str) -> ! {
1007 self.sess.span_diagnostic.span_bug(sp, m)
1009 pub fn abort_if_errors(&self) {
1010 self.sess.span_diagnostic.abort_if_errors();
1013 pub fn diagnostic(&self) -> &'a errors::Handler {
1014 &self.sess.span_diagnostic
1017 pub fn id_to_interned_str(&mut self, id: Ident) -> InternedString {
1021 /// Is the current token one of the keywords that signals a bare function
1023 pub fn token_is_bare_fn_keyword(&mut self) -> bool {
1024 self.check_keyword(keywords::Fn) ||
1025 self.check_keyword(keywords::Unsafe) ||
1026 self.check_keyword(keywords::Extern)
1029 pub fn get_lifetime(&mut self) -> ast::Ident {
1031 token::Lifetime(ref ident) => *ident,
1032 _ => self.bug("not a lifetime"),
1036 pub fn parse_for_in_type(&mut self) -> PResult<'a, Ty_> {
1038 Parses whatever can come after a `for` keyword in a type.
1039 The `for` has already been consumed.
1043 - for <'lt> |S| -> T
1047 - for <'lt> [unsafe] [extern "ABI"] fn (S) -> T
1048 - for <'lt> path::foo(a, b)
1053 let lo = self.span.lo;
1055 let lifetime_defs = try!(self.parse_late_bound_lifetime_defs());
1057 // examine next token to decide to do
1058 if self.token_is_bare_fn_keyword() {
1059 self.parse_ty_bare_fn(lifetime_defs)
1061 let hi = self.span.hi;
1062 let trait_ref = try!(self.parse_trait_ref());
1063 let poly_trait_ref = ast::PolyTraitRef { bound_lifetimes: lifetime_defs,
1064 trait_ref: trait_ref,
1065 span: mk_sp(lo, hi)};
1066 let other_bounds = if try!(self.eat(&token::BinOp(token::Plus)) ){
1067 try!(self.parse_ty_param_bounds(BoundParsingMode::Bare))
1072 Some(TraitTyParamBound(poly_trait_ref, TraitBoundModifier::None)).into_iter()
1073 .chain(other_bounds.into_vec())
1075 Ok(ast::TyPolyTraitRef(all_bounds))
1079 pub fn parse_ty_path(&mut self) -> PResult<'a, Ty_> {
1080 Ok(TyPath(None, try!(self.parse_path(LifetimeAndTypesWithoutColons))))
1083 /// parse a TyBareFn type:
1084 pub fn parse_ty_bare_fn(&mut self, lifetime_defs: Vec<ast::LifetimeDef>) -> PResult<'a, Ty_> {
1087 [unsafe] [extern "ABI"] fn <'lt> (S) -> T
1088 ^~~~^ ^~~~^ ^~~~^ ^~^ ^
1091 | | | Argument types
1097 let unsafety = try!(self.parse_unsafety());
1098 let abi = if try!(self.eat_keyword(keywords::Extern) ){
1099 try!(self.parse_opt_abi()).unwrap_or(abi::C)
1104 try!(self.expect_keyword(keywords::Fn));
1105 let (inputs, variadic) = try!(self.parse_fn_args(false, true));
1106 let ret_ty = try!(self.parse_ret_ty());
1107 let decl = P(FnDecl {
1112 Ok(TyBareFn(P(BareFnTy {
1115 lifetimes: lifetime_defs,
1120 /// Parses an obsolete closure kind (`&:`, `&mut:`, or `:`).
1121 pub fn parse_obsolete_closure_kind(&mut self) -> PResult<'a, ()> {
1122 let lo = self.span.lo;
1124 self.check(&token::BinOp(token::And)) &&
1125 self.look_ahead(1, |t| t.is_keyword(keywords::Mut)) &&
1126 self.look_ahead(2, |t| *t == token::Colon)
1132 self.token == token::BinOp(token::And) &&
1133 self.look_ahead(1, |t| *t == token::Colon)
1138 try!(self.eat(&token::Colon))
1145 let span = mk_sp(lo, self.span.hi);
1146 self.obsolete(span, ObsoleteSyntax::ClosureKind);
1150 pub fn parse_unsafety(&mut self) -> PResult<'a, Unsafety> {
1151 if try!(self.eat_keyword(keywords::Unsafe)) {
1152 return Ok(Unsafety::Unsafe);
1154 return Ok(Unsafety::Normal);
1158 /// Parse the items in a trait declaration
1159 pub fn parse_trait_items(&mut self) -> PResult<'a, Vec<P<TraitItem>>> {
1160 self.parse_unspanned_seq(
1161 &token::OpenDelim(token::Brace),
1162 &token::CloseDelim(token::Brace),
1164 |p| -> PResult<'a, P<TraitItem>> {
1165 maybe_whole!(no_clone p, NtTraitItem);
1166 let mut attrs = try!(p.parse_outer_attributes());
1169 let (name, node) = if try!(p.eat_keyword(keywords::Type)) {
1170 let TyParam {ident, bounds, default, ..} = try!(p.parse_ty_param());
1171 try!(p.expect(&token::Semi));
1172 (ident, TypeTraitItem(bounds, default))
1173 } else if p.is_const_item() {
1174 try!(p.expect_keyword(keywords::Const));
1175 let ident = try!(p.parse_ident());
1176 try!(p.expect(&token::Colon));
1177 let ty = try!(p.parse_ty_sum());
1178 let default = if p.check(&token::Eq) {
1180 let expr = try!(p.parse_expr());
1181 try!(p.commit_expr_expecting(&expr, token::Semi));
1184 try!(p.expect(&token::Semi));
1187 (ident, ConstTraitItem(ty, default))
1189 let (constness, unsafety, abi) = try!(p.parse_fn_front_matter());
1191 let ident = try!(p.parse_ident());
1192 let mut generics = try!(p.parse_generics());
1194 let (explicit_self, d) = try!(p.parse_fn_decl_with_self(|p: &mut Parser<'a>|{
1195 // This is somewhat dubious; We don't want to allow
1196 // argument names to be left off if there is a
1198 p.parse_arg_general(false)
1201 generics.where_clause = try!(p.parse_where_clause());
1202 let sig = ast::MethodSig {
1204 constness: constness,
1208 explicit_self: explicit_self,
1211 let body = match p.token {
1214 debug!("parse_trait_methods(): parsing required method");
1217 token::OpenDelim(token::Brace) => {
1218 debug!("parse_trait_methods(): parsing provided method");
1219 let (inner_attrs, body) =
1220 try!(p.parse_inner_attrs_and_block());
1221 attrs.extend(inner_attrs.iter().cloned());
1226 let token_str = p.this_token_to_string();
1227 return Err(p.fatal(&format!("expected `;` or `{{`, found `{}`",
1231 (ident, ast::MethodTraitItem(sig, body))
1235 id: ast::DUMMY_NODE_ID,
1239 span: mk_sp(lo, p.last_span.hi),
1244 /// Parse a possibly mutable type
1245 pub fn parse_mt(&mut self) -> PResult<'a, MutTy> {
1246 let mutbl = try!(self.parse_mutability());
1247 let t = try!(self.parse_ty());
1248 Ok(MutTy { ty: t, mutbl: mutbl })
1251 /// Parse optional return type [ -> TY ] in function decl
1252 pub fn parse_ret_ty(&mut self) -> PResult<'a, FunctionRetTy> {
1253 if try!(self.eat(&token::RArrow) ){
1254 if try!(self.eat(&token::Not) ){
1255 Ok(NoReturn(self.last_span))
1257 Ok(Return(try!(self.parse_ty())))
1260 let pos = self.span.lo;
1261 Ok(DefaultReturn(mk_sp(pos, pos)))
1265 /// Parse a type in a context where `T1+T2` is allowed.
1266 pub fn parse_ty_sum(&mut self) -> PResult<'a, P<Ty>> {
1267 let lo = self.span.lo;
1268 let lhs = try!(self.parse_ty());
1270 if !try!(self.eat(&token::BinOp(token::Plus)) ){
1274 let bounds = try!(self.parse_ty_param_bounds(BoundParsingMode::Bare));
1276 // In type grammar, `+` is treated like a binary operator,
1277 // and hence both L and R side are required.
1278 if bounds.is_empty() {
1279 let last_span = self.last_span;
1280 self.span_err(last_span,
1281 "at least one type parameter bound \
1282 must be specified");
1285 let sp = mk_sp(lo, self.last_span.hi);
1286 let sum = ast::TyObjectSum(lhs, bounds);
1287 Ok(P(Ty {id: ast::DUMMY_NODE_ID, node: sum, span: sp}))
1291 pub fn parse_ty(&mut self) -> PResult<'a, P<Ty>> {
1292 maybe_whole!(no_clone self, NtTy);
1294 let lo = self.span.lo;
1296 let t = if self.check(&token::OpenDelim(token::Paren)) {
1299 // (t) is a parenthesized ty
1300 // (t,) is the type of a tuple with only one field,
1302 let mut ts = vec![];
1303 let mut last_comma = false;
1304 while self.token != token::CloseDelim(token::Paren) {
1305 ts.push(try!(self.parse_ty_sum()));
1306 if self.check(&token::Comma) {
1315 try!(self.expect(&token::CloseDelim(token::Paren)));
1316 if ts.len() == 1 && !last_comma {
1317 TyParen(ts.into_iter().nth(0).unwrap())
1321 } else if self.check(&token::BinOp(token::Star)) {
1322 // STAR POINTER (bare pointer?)
1324 TyPtr(try!(self.parse_ptr()))
1325 } else if self.check(&token::OpenDelim(token::Bracket)) {
1327 try!(self.expect(&token::OpenDelim(token::Bracket)));
1328 let t = try!(self.parse_ty_sum());
1330 // Parse the `; e` in `[ i32; e ]`
1331 // where `e` is a const expression
1332 let t = match try!(self.maybe_parse_fixed_length_of_vec()) {
1334 Some(suffix) => TyFixedLengthVec(t, suffix)
1336 try!(self.expect(&token::CloseDelim(token::Bracket)));
1338 } else if self.check(&token::BinOp(token::And)) ||
1339 self.token == token::AndAnd {
1341 try!(self.expect_and());
1342 try!(self.parse_borrowed_pointee())
1343 } else if self.check_keyword(keywords::For) {
1344 try!(self.parse_for_in_type())
1345 } else if self.token_is_bare_fn_keyword() {
1347 try!(self.parse_ty_bare_fn(Vec::new()))
1348 } else if try!(self.eat_keyword_noexpect(keywords::Typeof)) {
1350 // In order to not be ambiguous, the type must be surrounded by parens.
1351 try!(self.expect(&token::OpenDelim(token::Paren)));
1352 let e = try!(self.parse_expr());
1353 try!(self.expect(&token::CloseDelim(token::Paren)));
1355 } else if try!(self.eat_lt()) {
1358 try!(self.parse_qualified_path(NoTypesAllowed));
1360 TyPath(Some(qself), path)
1361 } else if self.check(&token::ModSep) ||
1362 self.token.is_ident() ||
1363 self.token.is_path() {
1364 let path = try!(self.parse_path(LifetimeAndTypesWithoutColons));
1365 if self.check(&token::Not) {
1368 let delim = try!(self.expect_open_delim());
1369 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
1371 |p| p.parse_token_tree()));
1372 let hi = self.span.hi;
1373 TyMac(spanned(lo, hi, Mac_ { path: path, tts: tts, ctxt: EMPTY_CTXT }))
1378 } else if try!(self.eat(&token::Underscore) ){
1379 // TYPE TO BE INFERRED
1382 let this_token_str = self.this_token_to_string();
1383 let msg = format!("expected type, found `{}`", this_token_str);
1384 return Err(self.fatal(&msg[..]));
1387 let sp = mk_sp(lo, self.last_span.hi);
1388 Ok(P(Ty {id: ast::DUMMY_NODE_ID, node: t, span: sp}))
1391 pub fn parse_borrowed_pointee(&mut self) -> PResult<'a, Ty_> {
1392 // look for `&'lt` or `&'foo ` and interpret `foo` as the region name:
1393 let opt_lifetime = try!(self.parse_opt_lifetime());
1395 let mt = try!(self.parse_mt());
1396 return Ok(TyRptr(opt_lifetime, mt));
1399 pub fn parse_ptr(&mut self) -> PResult<'a, MutTy> {
1400 let mutbl = if try!(self.eat_keyword(keywords::Mut) ){
1402 } else if try!(self.eat_keyword(keywords::Const) ){
1405 let span = self.last_span;
1407 "bare raw pointers are no longer allowed, you should \
1408 likely use `*mut T`, but otherwise `*T` is now \
1409 known as `*const T`");
1412 let t = try!(self.parse_ty());
1413 Ok(MutTy { ty: t, mutbl: mutbl })
1416 pub fn is_named_argument(&mut self) -> bool {
1417 let offset = match self.token {
1418 token::BinOp(token::And) => 1,
1420 _ if self.token.is_keyword(keywords::Mut) => 1,
1424 debug!("parser is_named_argument offset:{}", offset);
1427 is_plain_ident_or_underscore(&self.token)
1428 && self.look_ahead(1, |t| *t == token::Colon)
1430 self.look_ahead(offset, |t| is_plain_ident_or_underscore(t))
1431 && self.look_ahead(offset + 1, |t| *t == token::Colon)
1435 /// This version of parse arg doesn't necessarily require
1436 /// identifier names.
1437 pub fn parse_arg_general(&mut self, require_name: bool) -> PResult<'a, Arg> {
1438 maybe_whole!(no_clone self, NtArg);
1440 let pat = if require_name || self.is_named_argument() {
1441 debug!("parse_arg_general parse_pat (require_name:{})",
1443 let pat = try!(self.parse_pat());
1445 try!(self.expect(&token::Colon));
1448 debug!("parse_arg_general ident_to_pat");
1449 ast_util::ident_to_pat(ast::DUMMY_NODE_ID,
1451 special_idents::invalid)
1454 let t = try!(self.parse_ty_sum());
1459 id: ast::DUMMY_NODE_ID,
1463 /// Parse a single function argument
1464 pub fn parse_arg(&mut self) -> PResult<'a, Arg> {
1465 self.parse_arg_general(true)
1468 /// Parse an argument in a lambda header e.g. |arg, arg|
1469 pub fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> {
1470 let pat = try!(self.parse_pat());
1471 let t = if try!(self.eat(&token::Colon) ){
1472 try!(self.parse_ty_sum())
1475 id: ast::DUMMY_NODE_ID,
1477 span: mk_sp(self.span.lo, self.span.hi),
1483 id: ast::DUMMY_NODE_ID
1487 pub fn maybe_parse_fixed_length_of_vec(&mut self) -> PResult<'a, Option<P<ast::Expr>>> {
1488 if self.check(&token::Semi) {
1490 Ok(Some(try!(self.parse_expr())))
1496 /// Matches token_lit = LIT_INTEGER | ...
1497 pub fn lit_from_token(&self, tok: &token::Token) -> PResult<'a, Lit_> {
1499 token::Interpolated(token::NtExpr(ref v)) => {
1501 ExprLit(ref lit) => { Ok(lit.node.clone()) }
1502 _ => { return Err(self.unexpected_last(tok)); }
1505 token::Literal(lit, suf) => {
1506 let (suffix_illegal, out) = match lit {
1507 token::Byte(i) => (true, LitByte(parse::byte_lit(&i.as_str()).0)),
1508 token::Char(i) => (true, LitChar(parse::char_lit(&i.as_str()).0)),
1510 // there are some valid suffixes for integer and
1511 // float literals, so all the handling is done
1513 token::Integer(s) => {
1514 (false, parse::integer_lit(&s.as_str(),
1515 suf.as_ref().map(|s| s.as_str()),
1516 &self.sess.span_diagnostic,
1519 token::Float(s) => {
1520 (false, parse::float_lit(&s.as_str(),
1521 suf.as_ref().map(|s| s.as_str()),
1522 &self.sess.span_diagnostic,
1528 LitStr(token::intern_and_get_ident(&parse::str_lit(&s.as_str())),
1531 token::StrRaw(s, n) => {
1534 token::intern_and_get_ident(&parse::raw_str_lit(&s.as_str())),
1537 token::ByteStr(i) =>
1538 (true, LitByteStr(parse::byte_str_lit(&i.as_str()))),
1539 token::ByteStrRaw(i, _) =>
1541 LitByteStr(Rc::new(i.to_string().into_bytes()))),
1545 let sp = self.last_span;
1546 self.expect_no_suffix(sp, &*format!("{} literal", lit.short_name()), suf)
1551 _ => { return Err(self.unexpected_last(tok)); }
1555 /// Matches lit = true | false | token_lit
1556 pub fn parse_lit(&mut self) -> PResult<'a, Lit> {
1557 let lo = self.span.lo;
1558 let lit = if try!(self.eat_keyword(keywords::True) ){
1560 } else if try!(self.eat_keyword(keywords::False) ){
1563 let token = try!(self.bump_and_get());
1564 let lit = try!(self.lit_from_token(&token));
1567 Ok(codemap::Spanned { node: lit, span: mk_sp(lo, self.last_span.hi) })
1570 /// matches '-' lit | lit
1571 pub fn parse_pat_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
1572 let minus_lo = self.span.lo;
1573 let minus_present = try!(self.eat(&token::BinOp(token::Minus)));
1574 let lo = self.span.lo;
1575 let literal = P(try!(self.parse_lit()));
1576 let hi = self.last_span.hi;
1577 let expr = self.mk_expr(lo, hi, ExprLit(literal), None);
1580 let minus_hi = self.last_span.hi;
1581 let unary = self.mk_unary(UnNeg, expr);
1582 Ok(self.mk_expr(minus_lo, minus_hi, unary, None))
1588 /// Parses qualified path.
1590 /// Assumes that the leading `<` has been parsed already.
1592 /// Qualifed paths are a part of the universal function call
1595 /// `qualified_path = <type [as trait_ref]>::path`
1597 /// See `parse_path` for `mode` meaning.
1602 /// `<T as U>::F::a::<S>`
1603 pub fn parse_qualified_path(&mut self, mode: PathParsingMode)
1604 -> PResult<'a, (QSelf, ast::Path)> {
1605 let span = self.last_span;
1606 let self_type = try!(self.parse_ty_sum());
1607 let mut path = if try!(self.eat_keyword(keywords::As)) {
1608 try!(self.parse_path(LifetimeAndTypesWithoutColons))
1619 position: path.segments.len()
1622 try!(self.expect(&token::Gt));
1623 try!(self.expect(&token::ModSep));
1625 let segments = match mode {
1626 LifetimeAndTypesWithoutColons => {
1627 try!(self.parse_path_segments_without_colons())
1629 LifetimeAndTypesWithColons => {
1630 try!(self.parse_path_segments_with_colons())
1633 try!(self.parse_path_segments_without_types())
1636 path.segments.extend(segments);
1638 path.span.hi = self.last_span.hi;
1643 /// Parses a path and optional type parameter bounds, depending on the
1644 /// mode. The `mode` parameter determines whether lifetimes, types, and/or
1645 /// bounds are permitted and whether `::` must precede type parameter
1647 pub fn parse_path(&mut self, mode: PathParsingMode) -> PResult<'a, ast::Path> {
1648 // Check for a whole path...
1649 let found = match self.token {
1650 token::Interpolated(token::NtPath(_)) => Some(try!(self.bump_and_get())),
1653 if let Some(token::Interpolated(token::NtPath(path))) = found {
1657 let lo = self.span.lo;
1658 let is_global = try!(self.eat(&token::ModSep));
1660 // Parse any number of segments and bound sets. A segment is an
1661 // identifier followed by an optional lifetime and a set of types.
1662 // A bound set is a set of type parameter bounds.
1663 let segments = match mode {
1664 LifetimeAndTypesWithoutColons => {
1665 try!(self.parse_path_segments_without_colons())
1667 LifetimeAndTypesWithColons => {
1668 try!(self.parse_path_segments_with_colons())
1671 try!(self.parse_path_segments_without_types())
1675 // Assemble the span.
1676 let span = mk_sp(lo, self.last_span.hi);
1678 // Assemble the result.
1687 /// - `a::b<T,U>::c<V,W>`
1688 /// - `a::b<T,U>::c(V) -> W`
1689 /// - `a::b<T,U>::c(V)`
1690 pub fn parse_path_segments_without_colons(&mut self) -> PResult<'a, Vec<ast::PathSegment>> {
1691 let mut segments = Vec::new();
1693 // First, parse an identifier.
1694 let identifier = try!(self.parse_ident_or_self_type());
1696 // Parse types, optionally.
1697 let parameters = if try!(self.eat_lt() ){
1698 let (lifetimes, types, bindings) = try!(self.parse_generic_values_after_lt());
1700 ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
1701 lifetimes: lifetimes,
1702 types: P::from_vec(types),
1703 bindings: P::from_vec(bindings),
1705 } else if try!(self.eat(&token::OpenDelim(token::Paren)) ){
1706 let lo = self.last_span.lo;
1708 let inputs = try!(self.parse_seq_to_end(
1709 &token::CloseDelim(token::Paren),
1710 seq_sep_trailing_allowed(token::Comma),
1711 |p| p.parse_ty_sum()));
1713 let output_ty = if try!(self.eat(&token::RArrow) ){
1714 Some(try!(self.parse_ty()))
1719 let hi = self.last_span.hi;
1721 ast::ParenthesizedParameters(ast::ParenthesizedParameterData {
1722 span: mk_sp(lo, hi),
1727 ast::PathParameters::none()
1730 // Assemble and push the result.
1731 segments.push(ast::PathSegment { identifier: identifier,
1732 parameters: parameters });
1734 // Continue only if we see a `::`
1735 if !try!(self.eat(&token::ModSep) ){
1736 return Ok(segments);
1742 /// - `a::b::<T,U>::c`
1743 pub fn parse_path_segments_with_colons(&mut self) -> PResult<'a, Vec<ast::PathSegment>> {
1744 let mut segments = Vec::new();
1746 // First, parse an identifier.
1747 let identifier = try!(self.parse_ident_or_self_type());
1749 // If we do not see a `::`, stop.
1750 if !try!(self.eat(&token::ModSep) ){
1751 segments.push(ast::PathSegment {
1752 identifier: identifier,
1753 parameters: ast::PathParameters::none()
1755 return Ok(segments);
1758 // Check for a type segment.
1759 if try!(self.eat_lt() ){
1760 // Consumed `a::b::<`, go look for types
1761 let (lifetimes, types, bindings) = try!(self.parse_generic_values_after_lt());
1762 segments.push(ast::PathSegment {
1763 identifier: identifier,
1764 parameters: ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
1765 lifetimes: lifetimes,
1766 types: P::from_vec(types),
1767 bindings: P::from_vec(bindings),
1771 // Consumed `a::b::<T,U>`, check for `::` before proceeding
1772 if !try!(self.eat(&token::ModSep) ){
1773 return Ok(segments);
1776 // Consumed `a::`, go look for `b`
1777 segments.push(ast::PathSegment {
1778 identifier: identifier,
1779 parameters: ast::PathParameters::none(),
1788 pub fn parse_path_segments_without_types(&mut self) -> PResult<'a, Vec<ast::PathSegment>> {
1789 let mut segments = Vec::new();
1791 // First, parse an identifier.
1792 let identifier = try!(self.parse_ident_or_self_type());
1794 // Assemble and push the result.
1795 segments.push(ast::PathSegment {
1796 identifier: identifier,
1797 parameters: ast::PathParameters::none()
1800 // If we do not see a `::`, stop.
1801 if !try!(self.eat(&token::ModSep) ){
1802 return Ok(segments);
1807 /// parses 0 or 1 lifetime
1808 pub fn parse_opt_lifetime(&mut self) -> PResult<'a, Option<ast::Lifetime>> {
1810 token::Lifetime(..) => {
1811 Ok(Some(try!(self.parse_lifetime())))
1819 /// Parses a single lifetime
1820 /// Matches lifetime = LIFETIME
1821 pub fn parse_lifetime(&mut self) -> PResult<'a, ast::Lifetime> {
1823 token::Lifetime(i) => {
1824 let span = self.span;
1826 return Ok(ast::Lifetime {
1827 id: ast::DUMMY_NODE_ID,
1833 return Err(self.fatal("expected a lifetime name"));
1838 /// Parses `lifetime_defs = [ lifetime_defs { ',' lifetime_defs } ]` where `lifetime_def =
1839 /// lifetime [':' lifetimes]`
1840 pub fn parse_lifetime_defs(&mut self) -> PResult<'a, Vec<ast::LifetimeDef>> {
1842 let mut res = Vec::new();
1845 token::Lifetime(_) => {
1846 let lifetime = try!(self.parse_lifetime());
1848 if try!(self.eat(&token::Colon) ){
1849 try!(self.parse_lifetimes(token::BinOp(token::Plus)))
1853 res.push(ast::LifetimeDef { lifetime: lifetime,
1863 token::Comma => { try!(self.bump());}
1864 token::Gt => { return Ok(res); }
1865 token::BinOp(token::Shr) => { return Ok(res); }
1867 let this_token_str = self.this_token_to_string();
1868 let msg = format!("expected `,` or `>` after lifetime \
1871 return Err(self.fatal(&msg[..]));
1877 /// matches lifetimes = ( lifetime ) | ( lifetime , lifetimes ) actually, it matches the empty
1878 /// one too, but putting that in there messes up the grammar....
1880 /// Parses zero or more comma separated lifetimes. Expects each lifetime to be followed by
1881 /// either a comma or `>`. Used when parsing type parameter lists, where we expect something
1882 /// like `<'a, 'b, T>`.
1883 pub fn parse_lifetimes(&mut self, sep: token::Token) -> PResult<'a, Vec<ast::Lifetime>> {
1885 let mut res = Vec::new();
1888 token::Lifetime(_) => {
1889 res.push(try!(self.parse_lifetime()));
1896 if self.token != sep {
1904 /// Parse mutability declaration (mut/const/imm)
1905 pub fn parse_mutability(&mut self) -> PResult<'a, Mutability> {
1906 if try!(self.eat_keyword(keywords::Mut) ){
1913 /// Parse ident COLON expr
1914 pub fn parse_field(&mut self) -> PResult<'a, Field> {
1915 let lo = self.span.lo;
1916 let i = try!(self.parse_ident());
1917 let hi = self.last_span.hi;
1918 try!(self.expect(&token::Colon));
1919 let e = try!(self.parse_expr());
1921 ident: spanned(lo, hi, i),
1922 span: mk_sp(lo, e.span.hi),
1927 pub fn mk_expr(&mut self, lo: BytePos, hi: BytePos,
1928 node: Expr_, attrs: ThinAttributes) -> P<Expr> {
1930 id: ast::DUMMY_NODE_ID,
1932 span: mk_sp(lo, hi),
1937 pub fn mk_unary(&mut self, unop: ast::UnOp, expr: P<Expr>) -> ast::Expr_ {
1938 ExprUnary(unop, expr)
1941 pub fn mk_binary(&mut self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::Expr_ {
1942 ExprBinary(binop, lhs, rhs)
1945 pub fn mk_call(&mut self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::Expr_ {
1949 fn mk_method_call(&mut self,
1950 ident: ast::SpannedIdent,
1954 ExprMethodCall(ident, tps, args)
1957 pub fn mk_index(&mut self, expr: P<Expr>, idx: P<Expr>) -> ast::Expr_ {
1958 ExprIndex(expr, idx)
1961 pub fn mk_range(&mut self,
1962 start: Option<P<Expr>>,
1963 end: Option<P<Expr>>)
1965 ExprRange(start, end)
1968 pub fn mk_field(&mut self, expr: P<Expr>, ident: ast::SpannedIdent) -> ast::Expr_ {
1969 ExprField(expr, ident)
1972 pub fn mk_tup_field(&mut self, expr: P<Expr>, idx: codemap::Spanned<usize>) -> ast::Expr_ {
1973 ExprTupField(expr, idx)
1976 pub fn mk_assign_op(&mut self, binop: ast::BinOp,
1977 lhs: P<Expr>, rhs: P<Expr>) -> ast::Expr_ {
1978 ExprAssignOp(binop, lhs, rhs)
1981 pub fn mk_mac_expr(&mut self, lo: BytePos, hi: BytePos,
1982 m: Mac_, attrs: ThinAttributes) -> P<Expr> {
1984 id: ast::DUMMY_NODE_ID,
1985 node: ExprMac(codemap::Spanned {node: m, span: mk_sp(lo, hi)}),
1986 span: mk_sp(lo, hi),
1991 pub fn mk_lit_u32(&mut self, i: u32, attrs: ThinAttributes) -> P<Expr> {
1992 let span = &self.span;
1993 let lv_lit = P(codemap::Spanned {
1994 node: LitInt(i as u64, ast::UnsignedIntLit(TyU32)),
1999 id: ast::DUMMY_NODE_ID,
2000 node: ExprLit(lv_lit),
2006 fn expect_open_delim(&mut self) -> PResult<'a, token::DelimToken> {
2007 self.expected_tokens.push(TokenType::Token(token::Gt));
2009 token::OpenDelim(delim) => {
2013 _ => Err(self.fatal("expected open delimiter")),
2017 /// At the bottom (top?) of the precedence hierarchy,
2018 /// parse things like parenthesized exprs,
2019 /// macros, return, etc.
2021 /// NB: This does not parse outer attributes,
2022 /// and is private because it only works
2023 /// correctly if called from parse_dot_or_call_expr().
2024 fn parse_bottom_expr(&mut self) -> PResult<'a, P<Expr>> {
2025 maybe_whole_expr!(self);
2027 // Outer attributes are already parsed and will be
2028 // added to the return value after the fact.
2030 // Therefore, prevent sub-parser from parsing
2031 // attributes by giving them a empty "already parsed" list.
2032 let mut attrs = None;
2034 let lo = self.span.lo;
2035 let mut hi = self.span.hi;
2039 // Note: when adding new syntax here, don't forget to adjust Token::can_begin_expr().
2041 token::OpenDelim(token::Paren) => {
2044 let attrs = try!(self.parse_inner_attributes())
2048 // (e) is parenthesized e
2049 // (e,) is a tuple with only one field, e
2050 let mut es = vec![];
2051 let mut trailing_comma = false;
2052 while self.token != token::CloseDelim(token::Paren) {
2053 es.push(try!(self.parse_expr()));
2054 try!(self.commit_expr(&**es.last().unwrap(), &[],
2055 &[token::Comma, token::CloseDelim(token::Paren)]));
2056 if self.check(&token::Comma) {
2057 trailing_comma = true;
2061 trailing_comma = false;
2067 hi = self.last_span.hi;
2068 return if es.len() == 1 && !trailing_comma {
2069 Ok(self.mk_expr(lo, hi, ExprParen(es.into_iter().nth(0).unwrap()), attrs))
2071 Ok(self.mk_expr(lo, hi, ExprTup(es), attrs))
2074 token::OpenDelim(token::Brace) => {
2075 return self.parse_block_expr(lo, DefaultBlock, attrs);
2077 token::BinOp(token::Or) | token::OrOr => {
2078 let lo = self.span.lo;
2079 return self.parse_lambda_expr(lo, CaptureByRef, attrs);
2081 token::Ident(id @ ast::Ident {
2082 name: token::SELF_KEYWORD_NAME,
2084 }, token::Plain) => {
2086 let path = ast_util::ident_to_path(mk_sp(lo, hi), id);
2087 ex = ExprPath(None, path);
2088 hi = self.last_span.hi;
2090 token::OpenDelim(token::Bracket) => {
2093 let inner_attrs = try!(self.parse_inner_attributes())
2095 attrs.update(|attrs| attrs.append(inner_attrs));
2097 if self.check(&token::CloseDelim(token::Bracket)) {
2100 ex = ExprVec(Vec::new());
2103 let first_expr = try!(self.parse_expr());
2104 if self.check(&token::Semi) {
2105 // Repeating array syntax: [ 0; 512 ]
2107 let count = try!(self.parse_expr());
2108 try!(self.expect(&token::CloseDelim(token::Bracket)));
2109 ex = ExprRepeat(first_expr, count);
2110 } else if self.check(&token::Comma) {
2111 // Vector with two or more elements.
2113 let remaining_exprs = try!(self.parse_seq_to_end(
2114 &token::CloseDelim(token::Bracket),
2115 seq_sep_trailing_allowed(token::Comma),
2116 |p| Ok(try!(p.parse_expr()))
2118 let mut exprs = vec!(first_expr);
2119 exprs.extend(remaining_exprs);
2120 ex = ExprVec(exprs);
2122 // Vector with one element.
2123 try!(self.expect(&token::CloseDelim(token::Bracket)));
2124 ex = ExprVec(vec!(first_expr));
2127 hi = self.last_span.hi;
2130 if try!(self.eat_lt()){
2132 try!(self.parse_qualified_path(LifetimeAndTypesWithColons));
2134 return Ok(self.mk_expr(lo, hi, ExprPath(Some(qself), path), attrs));
2136 if try!(self.eat_keyword(keywords::Move) ){
2137 let lo = self.last_span.lo;
2138 return self.parse_lambda_expr(lo, CaptureByValue, attrs);
2140 if try!(self.eat_keyword(keywords::If)) {
2141 return self.parse_if_expr(attrs);
2143 if try!(self.eat_keyword(keywords::For) ){
2144 let lo = self.last_span.lo;
2145 return self.parse_for_expr(None, lo, attrs);
2147 if try!(self.eat_keyword(keywords::While) ){
2148 let lo = self.last_span.lo;
2149 return self.parse_while_expr(None, lo, attrs);
2151 if self.token.is_lifetime() {
2152 let lifetime = self.get_lifetime();
2153 let lo = self.span.lo;
2155 try!(self.expect(&token::Colon));
2156 if try!(self.eat_keyword(keywords::While) ){
2157 return self.parse_while_expr(Some(lifetime), lo, attrs)
2159 if try!(self.eat_keyword(keywords::For) ){
2160 return self.parse_for_expr(Some(lifetime), lo, attrs)
2162 if try!(self.eat_keyword(keywords::Loop) ){
2163 return self.parse_loop_expr(Some(lifetime), lo, attrs)
2165 return Err(self.fatal("expected `while`, `for`, or `loop` after a label"))
2167 if try!(self.eat_keyword(keywords::Loop) ){
2168 let lo = self.last_span.lo;
2169 return self.parse_loop_expr(None, lo, attrs);
2171 if try!(self.eat_keyword(keywords::Continue) ){
2172 let ex = if self.token.is_lifetime() {
2173 let ex = ExprAgain(Some(Spanned{
2174 node: self.get_lifetime(),
2182 let hi = self.last_span.hi;
2183 return Ok(self.mk_expr(lo, hi, ex, attrs));
2185 if try!(self.eat_keyword(keywords::Match) ){
2186 return self.parse_match_expr(attrs);
2188 if try!(self.eat_keyword(keywords::Unsafe) ){
2189 return self.parse_block_expr(
2191 UnsafeBlock(ast::UserProvided),
2194 if try!(self.eat_keyword(keywords::Return) ){
2195 if self.token.can_begin_expr() {
2196 let e = try!(self.parse_expr());
2198 ex = ExprRet(Some(e));
2202 } else if try!(self.eat_keyword(keywords::Break) ){
2203 if self.token.is_lifetime() {
2204 ex = ExprBreak(Some(Spanned {
2205 node: self.get_lifetime(),
2210 ex = ExprBreak(None);
2212 hi = self.last_span.hi;
2213 } else if self.check(&token::ModSep) ||
2214 self.token.is_ident() &&
2215 !self.check_keyword(keywords::True) &&
2216 !self.check_keyword(keywords::False) {
2218 try!(self.parse_path(LifetimeAndTypesWithColons));
2220 // `!`, as an operator, is prefix, so we know this isn't that
2221 if self.check(&token::Not) {
2222 // MACRO INVOCATION expression
2225 let delim = try!(self.expect_open_delim());
2226 let tts = try!(self.parse_seq_to_end(
2227 &token::CloseDelim(delim),
2229 |p| p.parse_token_tree()));
2230 let hi = self.last_span.hi;
2232 return Ok(self.mk_mac_expr(lo,
2234 Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT },
2237 if self.check(&token::OpenDelim(token::Brace)) {
2238 // This is a struct literal, unless we're prohibited
2239 // from parsing struct literals here.
2240 let prohibited = self.restrictions.contains(
2241 Restrictions::RESTRICTION_NO_STRUCT_LITERAL
2244 // It's a struct literal.
2246 let mut fields = Vec::new();
2247 let mut base = None;
2249 let attrs = attrs.append(
2250 try!(self.parse_inner_attributes())
2251 .into_thin_attrs());
2253 while self.token != token::CloseDelim(token::Brace) {
2254 if try!(self.eat(&token::DotDot) ){
2255 base = Some(try!(self.parse_expr()));
2259 fields.push(try!(self.parse_field()));
2260 try!(self.commit_expr(&*fields.last().unwrap().expr,
2262 &[token::CloseDelim(token::Brace)]));
2266 try!(self.expect(&token::CloseDelim(token::Brace)));
2267 ex = ExprStruct(pth, fields, base);
2268 return Ok(self.mk_expr(lo, hi, ex, attrs));
2273 ex = ExprPath(None, pth);
2275 // other literal expression
2276 let lit = try!(self.parse_lit());
2278 ex = ExprLit(P(lit));
2283 return Ok(self.mk_expr(lo, hi, ex, attrs));
2286 fn parse_or_use_outer_attributes(&mut self,
2287 already_parsed_attrs: Option<ThinAttributes>)
2288 -> PResult<'a, ThinAttributes> {
2289 if let Some(attrs) = already_parsed_attrs {
2292 self.parse_outer_attributes().map(|a| a.into_thin_attrs())
2296 /// Parse a block or unsafe block
2297 pub fn parse_block_expr(&mut self, lo: BytePos, blk_mode: BlockCheckMode,
2298 attrs: ThinAttributes)
2299 -> PResult<'a, P<Expr>> {
2301 let outer_attrs = attrs;
2302 try!(self.expect(&token::OpenDelim(token::Brace)));
2304 let inner_attrs = try!(self.parse_inner_attributes()).into_thin_attrs();
2305 let attrs = outer_attrs.append(inner_attrs);
2307 let blk = try!(self.parse_block_tail(lo, blk_mode));
2308 return Ok(self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk), attrs));
2311 /// parse a.b or a(13) or a[4] or just a
2312 pub fn parse_dot_or_call_expr(&mut self,
2313 already_parsed_attrs: Option<ThinAttributes>)
2314 -> PResult<'a, P<Expr>> {
2315 let attrs = try!(self.parse_or_use_outer_attributes(already_parsed_attrs));
2317 let b = try!(self.parse_bottom_expr());
2318 self.parse_dot_or_call_expr_with(b, attrs)
2321 pub fn parse_dot_or_call_expr_with(&mut self,
2323 attrs: ThinAttributes)
2324 -> PResult<'a, P<Expr>> {
2325 // Stitch the list of outer attributes onto the return value.
2326 // A little bit ugly, but the best way given the current code
2328 self.parse_dot_or_call_expr_with_(e0)
2330 expr.map(|mut expr| {
2331 expr.attrs.update(|a| a.prepend(attrs));
2333 ExprIf(..) | ExprIfLet(..) => {
2334 if !expr.attrs.as_attr_slice().is_empty() {
2335 // Just point to the first attribute in there...
2336 let span = expr.attrs.as_attr_slice()[0].span;
2339 "attributes are not yet allowed on `if` \
2350 fn parse_dot_or_call_expr_with_(&mut self, e0: P<Expr>) -> PResult<'a, P<Expr>> {
2356 if try!(self.eat(&token::Dot) ){
2358 token::Ident(i, _) => {
2359 let dot = self.last_span.hi;
2362 let (_, tys, bindings) = if try!(self.eat(&token::ModSep) ){
2363 try!(self.expect_lt());
2364 try!(self.parse_generic_values_after_lt())
2366 (Vec::new(), Vec::new(), Vec::new())
2369 if !bindings.is_empty() {
2370 let last_span = self.last_span;
2371 self.span_err(last_span, "type bindings are only permitted on trait paths");
2374 // expr.f() method call
2376 token::OpenDelim(token::Paren) => {
2377 let mut es = try!(self.parse_unspanned_seq(
2378 &token::OpenDelim(token::Paren),
2379 &token::CloseDelim(token::Paren),
2380 seq_sep_trailing_allowed(token::Comma),
2381 |p| Ok(try!(p.parse_expr()))
2383 hi = self.last_span.hi;
2386 let id = spanned(dot, hi, i);
2387 let nd = self.mk_method_call(id, tys, es);
2388 e = self.mk_expr(lo, hi, nd, None);
2391 if !tys.is_empty() {
2392 let last_span = self.last_span;
2393 self.span_err(last_span,
2394 "field expressions may not \
2395 have type parameters");
2398 let id = spanned(dot, hi, i);
2399 let field = self.mk_field(e, id);
2400 e = self.mk_expr(lo, hi, field, None);
2404 token::Literal(token::Integer(n), suf) => {
2407 // A tuple index may not have a suffix
2408 self.expect_no_suffix(sp, "tuple index", suf);
2410 let dot = self.last_span.hi;
2414 let index = n.as_str().parse::<usize>().ok();
2417 let id = spanned(dot, hi, n);
2418 let field = self.mk_tup_field(e, id);
2419 e = self.mk_expr(lo, hi, field, None);
2422 let last_span = self.last_span;
2423 self.span_err(last_span, "invalid tuple or tuple struct index");
2427 token::Literal(token::Float(n), _suf) => {
2429 let last_span = self.last_span;
2430 let fstr = n.as_str();
2431 let mut err = self.diagnostic().struct_span_err(last_span,
2432 &format!("unexpected token: `{}`", n.as_str()));
2433 if fstr.chars().all(|x| "0123456789.".contains(x)) {
2434 let float = match fstr.parse::<f64>().ok() {
2438 err.fileline_help(last_span,
2439 &format!("try parenthesizing the first index; e.g., `(foo.{}){}`",
2440 float.trunc() as usize,
2441 format!(".{}", fstr.splitn(2, ".").last().unwrap())));
2444 self.abort_if_errors();
2447 _ => return Err(self.unexpected())
2451 if self.expr_is_complete(&*e) { break; }
2454 token::OpenDelim(token::Paren) => {
2455 let es = try!(self.parse_unspanned_seq(
2456 &token::OpenDelim(token::Paren),
2457 &token::CloseDelim(token::Paren),
2458 seq_sep_trailing_allowed(token::Comma),
2459 |p| Ok(try!(p.parse_expr()))
2461 hi = self.last_span.hi;
2463 let nd = self.mk_call(e, es);
2464 e = self.mk_expr(lo, hi, nd, None);
2468 // Could be either an index expression or a slicing expression.
2469 token::OpenDelim(token::Bracket) => {
2471 let ix = try!(self.parse_expr());
2473 try!(self.commit_expr_expecting(&*ix, token::CloseDelim(token::Bracket)));
2474 let index = self.mk_index(e, ix);
2475 e = self.mk_expr(lo, hi, index, None)
2483 // Parse unquoted tokens after a `$` in a token tree
2484 fn parse_unquoted(&mut self) -> PResult<'a, TokenTree> {
2485 let mut sp = self.span;
2486 let (name, namep) = match self.token {
2490 if self.token == token::OpenDelim(token::Paren) {
2491 let Spanned { node: seq, span: seq_span } = try!(self.parse_seq(
2492 &token::OpenDelim(token::Paren),
2493 &token::CloseDelim(token::Paren),
2495 |p| p.parse_token_tree()
2497 let (sep, repeat) = try!(self.parse_sep_and_kleene_op());
2498 let name_num = macro_parser::count_names(&seq);
2499 return Ok(TokenTree::Sequence(mk_sp(sp.lo, seq_span.hi),
2500 Rc::new(SequenceRepetition {
2504 num_captures: name_num
2506 } else if self.token.is_keyword_allow_following_colon(keywords::Crate) {
2508 return Ok(TokenTree::Token(sp, SpecialVarNt(SpecialMacroVar::CrateMacroVar)));
2510 sp = mk_sp(sp.lo, self.span.hi);
2511 let namep = match self.token { token::Ident(_, p) => p, _ => token::Plain };
2512 let name = try!(self.parse_ident());
2516 token::SubstNt(name, namep) => {
2522 // continue by trying to parse the `:ident` after `$name`
2523 if self.token == token::Colon && self.look_ahead(1, |t| t.is_ident() &&
2524 !t.is_strict_keyword() &&
2525 !t.is_reserved_keyword()) {
2527 sp = mk_sp(sp.lo, self.span.hi);
2528 let kindp = match self.token { token::Ident(_, p) => p, _ => token::Plain };
2529 let nt_kind = try!(self.parse_ident());
2530 Ok(TokenTree::Token(sp, MatchNt(name, nt_kind, namep, kindp)))
2532 Ok(TokenTree::Token(sp, SubstNt(name, namep)))
2536 pub fn check_unknown_macro_variable(&mut self) -> PResult<'a, ()> {
2537 if self.quote_depth == 0 {
2539 token::SubstNt(name, _) =>
2540 return Err(self.fatal(&format!("unknown macro variable `{}`",
2548 /// Parse an optional separator followed by a Kleene-style
2549 /// repetition token (+ or *).
2550 pub fn parse_sep_and_kleene_op(&mut self)
2551 -> PResult<'a, (Option<token::Token>, ast::KleeneOp)> {
2552 fn parse_kleene_op<'a>(parser: &mut Parser<'a>) -> PResult<'a, Option<ast::KleeneOp>> {
2553 match parser.token {
2554 token::BinOp(token::Star) => {
2555 try!(parser.bump());
2556 Ok(Some(ast::ZeroOrMore))
2558 token::BinOp(token::Plus) => {
2559 try!(parser.bump());
2560 Ok(Some(ast::OneOrMore))
2566 match try!(parse_kleene_op(self)) {
2567 Some(kleene_op) => return Ok((None, kleene_op)),
2571 let separator = try!(self.bump_and_get());
2572 match try!(parse_kleene_op(self)) {
2573 Some(zerok) => Ok((Some(separator), zerok)),
2574 None => return Err(self.fatal("expected `*` or `+`"))
2578 /// parse a single token tree from the input.
2579 pub fn parse_token_tree(&mut self) -> PResult<'a, TokenTree> {
2580 // FIXME #6994: currently, this is too eager. It
2581 // parses token trees but also identifies TokenType::Sequence's
2582 // and token::SubstNt's; it's too early to know yet
2583 // whether something will be a nonterminal or a seq
2585 maybe_whole!(deref self, NtTT);
2587 // this is the fall-through for the 'match' below.
2588 // invariants: the current token is not a left-delimiter,
2589 // not an EOF, and not the desired right-delimiter (if
2590 // it were, parse_seq_to_before_end would have prevented
2591 // reaching this point.
2592 fn parse_non_delim_tt_tok<'b>(p: &mut Parser<'b>) -> PResult<'b, TokenTree> {
2593 maybe_whole!(deref p, NtTT);
2595 token::CloseDelim(_) => {
2596 let token_str = p.this_token_to_string();
2597 let mut err = p.fatal(
2598 &format!("incorrect close delimiter: `{}`", token_str));
2599 // This is a conservative error: only report the last unclosed delimiter. The
2600 // previous unclosed delimiters could actually be closed! The parser just hasn't
2601 // gotten to them yet.
2602 if let Some(&sp) = p.open_braces.last() {
2603 err.span_note(sp, "unclosed delimiter");
2607 /* we ought to allow different depths of unquotation */
2608 token::Dollar | token::SubstNt(..) if p.quote_depth > 0 => {
2612 Ok(TokenTree::Token(p.span, try!(p.bump_and_get())))
2619 let open_braces = self.open_braces.clone();
2620 let mut err: DiagnosticBuilder<'a> =
2621 self.fatal("this file contains an un-closed delimiter");
2622 for sp in &open_braces {
2623 err.span_help(*sp, "did you mean to close this delimiter?");
2627 token::OpenDelim(delim) => {
2628 // The span for beginning of the delimited section
2629 let pre_span = self.span;
2631 // Parse the open delimiter.
2632 self.open_braces.push(self.span);
2633 let open_span = self.span;
2636 // Parse the token trees within the delimiters
2637 let tts = try!(self.parse_seq_to_before_end(
2638 &token::CloseDelim(delim),
2640 |p| p.parse_token_tree()
2643 // Parse the close delimiter.
2644 let close_span = self.span;
2646 self.open_braces.pop().unwrap();
2648 // Expand to cover the entire delimited token tree
2649 let span = Span { hi: close_span.hi, ..pre_span };
2651 Ok(TokenTree::Delimited(span, Rc::new(Delimited {
2653 open_span: open_span,
2655 close_span: close_span,
2658 _ => parse_non_delim_tt_tok(self),
2662 // parse a stream of tokens into a list of TokenTree's,
2664 pub fn parse_all_token_trees(&mut self) -> PResult<'a, Vec<TokenTree>> {
2665 let mut tts = Vec::new();
2666 while self.token != token::Eof {
2667 tts.push(try!(self.parse_token_tree()));
2672 /// Parse a prefix-unary-operator expr
2673 pub fn parse_prefix_expr(&mut self,
2674 already_parsed_attrs: Option<ThinAttributes>)
2675 -> PResult<'a, P<Expr>> {
2676 let attrs = try!(self.parse_or_use_outer_attributes(already_parsed_attrs));
2677 let lo = self.span.lo;
2679 // Note: when adding new unary operators, don't forget to adjust Token::can_begin_expr()
2680 let ex = match self.token {
2683 let e = try!(self.parse_prefix_expr(None));
2685 self.mk_unary(UnNot, e)
2687 token::BinOp(token::Minus) => {
2689 let e = try!(self.parse_prefix_expr(None));
2691 self.mk_unary(UnNeg, e)
2693 token::BinOp(token::Star) => {
2695 let e = try!(self.parse_prefix_expr(None));
2697 self.mk_unary(UnDeref, e)
2699 token::BinOp(token::And) | token::AndAnd => {
2700 try!(self.expect_and());
2701 let m = try!(self.parse_mutability());
2702 let e = try!(self.parse_prefix_expr(None));
2706 token::Ident(..) if self.token.is_keyword(keywords::In) => {
2708 let place = try!(self.parse_expr_res(
2709 Restrictions::RESTRICTION_NO_STRUCT_LITERAL,
2712 let blk = try!(self.parse_block());
2713 let span = blk.span;
2715 let blk_expr = self.mk_expr(span.lo, span.hi, ExprBlock(blk),
2717 ExprInPlace(place, blk_expr)
2719 token::Ident(..) if self.token.is_keyword(keywords::Box) => {
2721 let subexpression = try!(self.parse_prefix_expr(None));
2722 hi = subexpression.span.hi;
2723 ExprBox(subexpression)
2725 _ => return self.parse_dot_or_call_expr(Some(attrs))
2727 return Ok(self.mk_expr(lo, hi, ex, attrs));
2730 /// Parse an associative expression
2732 /// This parses an expression accounting for associativity and precedence of the operators in
2734 pub fn parse_assoc_expr(&mut self,
2735 already_parsed_attrs: Option<ThinAttributes>)
2736 -> PResult<'a, P<Expr>> {
2737 self.parse_assoc_expr_with(0, already_parsed_attrs.into())
2740 /// Parse an associative expression with operators of at least `min_prec` precedence
2741 pub fn parse_assoc_expr_with(&mut self,
2744 -> PResult<'a, P<Expr>> {
2745 let mut lhs = if let LhsExpr::AlreadyParsed(expr) = lhs {
2748 let attrs = match lhs {
2749 LhsExpr::AttributesParsed(attrs) => Some(attrs),
2752 if self.token == token::DotDot {
2753 return self.parse_prefix_range_expr(attrs);
2755 try!(self.parse_prefix_expr(attrs))
2758 if self.expr_is_complete(&*lhs) {
2759 // Semi-statement forms are odd. See https://github.com/rust-lang/rust/issues/29071
2762 self.expected_tokens.push(TokenType::Operator);
2763 while let Some(op) = AssocOp::from_token(&self.token) {
2764 let cur_op_span = self.span;
2765 let restrictions = if op.is_assign_like() {
2766 self.restrictions & Restrictions::RESTRICTION_NO_STRUCT_LITERAL
2770 if op.precedence() < min_prec {
2774 if op.is_comparison() {
2775 self.check_no_chained_comparison(&*lhs, &op);
2778 if op == AssocOp::As {
2779 let rhs = try!(self.parse_ty());
2780 lhs = self.mk_expr(lhs.span.lo, rhs.span.hi,
2781 ExprCast(lhs, rhs), None);
2783 } else if op == AssocOp::Colon {
2784 let rhs = try!(self.parse_ty());
2785 lhs = self.mk_expr(lhs.span.lo, rhs.span.hi,
2786 ExprType(lhs, rhs), None);
2788 } else if op == AssocOp::DotDot {
2789 // If we didn’t have to handle `x..`, it would be pretty easy to generalise
2790 // it to the Fixity::None code.
2792 // We have 2 alternatives here: `x..y` and `x..` The other two variants are
2793 // handled with `parse_prefix_range_expr` call above.
2794 let rhs = if self.is_at_start_of_range_notation_rhs() {
2795 self.parse_assoc_expr_with(op.precedence() + 1,
2796 LhsExpr::NotYetParsed).ok()
2800 let (lhs_span, rhs_span) = (lhs.span, if let Some(ref x) = rhs {
2805 let r = self.mk_range(Some(lhs), rhs);
2806 lhs = self.mk_expr(lhs_span.lo, rhs_span.hi, r, None);
2810 let rhs = try!(match op.fixity() {
2811 Fixity::Right => self.with_res(restrictions, |this|{
2812 this.parse_assoc_expr_with(op.precedence(), LhsExpr::NotYetParsed)
2814 Fixity::Left => self.with_res(restrictions, |this|{
2815 this.parse_assoc_expr_with(op.precedence() + 1, LhsExpr::NotYetParsed)
2817 // We currently have no non-associative operators that are not handled above by
2818 // the special cases. The code is here only for future convenience.
2819 Fixity::None => self.with_res(restrictions, |this|{
2820 this.parse_assoc_expr_with(op.precedence() + 1, LhsExpr::NotYetParsed)
2825 AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide |
2826 AssocOp::Modulus | AssocOp::LAnd | AssocOp::LOr | AssocOp::BitXor |
2827 AssocOp::BitAnd | AssocOp::BitOr | AssocOp::ShiftLeft | AssocOp::ShiftRight |
2828 AssocOp::Equal | AssocOp::Less | AssocOp::LessEqual | AssocOp::NotEqual |
2829 AssocOp::Greater | AssocOp::GreaterEqual => {
2830 let ast_op = op.to_ast_binop().unwrap();
2831 let (lhs_span, rhs_span) = (lhs.span, rhs.span);
2832 let binary = self.mk_binary(codemap::respan(cur_op_span, ast_op), lhs, rhs);
2833 self.mk_expr(lhs_span.lo, rhs_span.hi, binary, None)
2836 self.mk_expr(lhs.span.lo, rhs.span.hi, ExprAssign(lhs, rhs), None),
2838 self.mk_expr(lhs.span.lo, rhs.span.hi, ExprInPlace(lhs, rhs), None),
2839 AssocOp::AssignOp(k) => {
2841 token::Plus => BiAdd,
2842 token::Minus => BiSub,
2843 token::Star => BiMul,
2844 token::Slash => BiDiv,
2845 token::Percent => BiRem,
2846 token::Caret => BiBitXor,
2847 token::And => BiBitAnd,
2848 token::Or => BiBitOr,
2849 token::Shl => BiShl,
2852 let (lhs_span, rhs_span) = (lhs.span, rhs.span);
2853 let aopexpr = self.mk_assign_op(codemap::respan(cur_op_span, aop), lhs, rhs);
2854 self.mk_expr(lhs_span.lo, rhs_span.hi, aopexpr, None)
2856 AssocOp::As | AssocOp::Colon | AssocOp::DotDot => {
2857 self.bug("As, Colon or DotDot branch reached")
2861 if op.fixity() == Fixity::None { break }
2866 /// Produce an error if comparison operators are chained (RFC #558).
2867 /// We only need to check lhs, not rhs, because all comparison ops
2868 /// have same precedence and are left-associative
2869 fn check_no_chained_comparison(&mut self, lhs: &Expr, outer_op: &AssocOp) {
2870 debug_assert!(outer_op.is_comparison());
2872 ExprBinary(op, _, _) if op.node.is_comparison() => {
2873 // respan to include both operators
2874 let op_span = mk_sp(op.span.lo, self.span.hi);
2875 let mut err = self.diagnostic().struct_span_err(op_span,
2876 "chained comparison operators require parentheses");
2877 if op.node == BiLt && *outer_op == AssocOp::Greater {
2878 err.fileline_help(op_span,
2879 "use `::<...>` instead of `<...>` if you meant to specify type arguments");
2887 /// Parse prefix-forms of range notation: `..expr` and `..`
2888 fn parse_prefix_range_expr(&mut self,
2889 already_parsed_attrs: Option<ThinAttributes>)
2890 -> PResult<'a, P<Expr>> {
2891 debug_assert!(self.token == token::DotDot);
2892 let attrs = try!(self.parse_or_use_outer_attributes(already_parsed_attrs));
2893 let lo = self.span.lo;
2894 let mut hi = self.span.hi;
2896 let opt_end = if self.is_at_start_of_range_notation_rhs() {
2897 // RHS must be parsed with more associativity than DotDot.
2898 let next_prec = AssocOp::from_token(&token::DotDot).unwrap().precedence() + 1;
2899 Some(try!(self.parse_assoc_expr_with(next_prec,
2900 LhsExpr::NotYetParsed)
2908 let r = self.mk_range(None, opt_end);
2909 Ok(self.mk_expr(lo, hi, r, attrs))
2912 fn is_at_start_of_range_notation_rhs(&self) -> bool {
2913 if self.token.can_begin_expr() {
2914 // parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
2915 if self.token == token::OpenDelim(token::Brace) {
2916 return !self.restrictions.contains(Restrictions::RESTRICTION_NO_STRUCT_LITERAL);
2924 /// Parse an 'if' or 'if let' expression ('if' token already eaten)
2925 pub fn parse_if_expr(&mut self, attrs: ThinAttributes) -> PResult<'a, P<Expr>> {
2926 if self.check_keyword(keywords::Let) {
2927 return self.parse_if_let_expr(attrs);
2929 let lo = self.last_span.lo;
2930 let cond = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
2931 let thn = try!(self.parse_block());
2932 let mut els: Option<P<Expr>> = None;
2933 let mut hi = thn.span.hi;
2934 if try!(self.eat_keyword(keywords::Else) ){
2935 let elexpr = try!(self.parse_else_expr());
2936 hi = elexpr.span.hi;
2939 Ok(self.mk_expr(lo, hi, ExprIf(cond, thn, els), attrs))
2942 /// Parse an 'if let' expression ('if' token already eaten)
2943 pub fn parse_if_let_expr(&mut self, attrs: ThinAttributes)
2944 -> PResult<'a, P<Expr>> {
2945 let lo = self.last_span.lo;
2946 try!(self.expect_keyword(keywords::Let));
2947 let pat = try!(self.parse_pat());
2948 try!(self.expect(&token::Eq));
2949 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
2950 let thn = try!(self.parse_block());
2951 let (hi, els) = if try!(self.eat_keyword(keywords::Else) ){
2952 let expr = try!(self.parse_else_expr());
2953 (expr.span.hi, Some(expr))
2957 Ok(self.mk_expr(lo, hi, ExprIfLet(pat, expr, thn, els), attrs))
2961 pub fn parse_lambda_expr(&mut self, lo: BytePos,
2962 capture_clause: CaptureClause,
2963 attrs: ThinAttributes)
2964 -> PResult<'a, P<Expr>>
2966 let decl = try!(self.parse_fn_block_decl());
2967 let body = match decl.output {
2968 DefaultReturn(_) => {
2969 // If no explicit return type is given, parse any
2970 // expr and wrap it up in a dummy block:
2971 let body_expr = try!(self.parse_expr());
2973 id: ast::DUMMY_NODE_ID,
2975 span: body_expr.span,
2976 expr: Some(body_expr),
2977 rules: DefaultBlock,
2981 // If an explicit return type is given, require a
2982 // block to appear (RFC 968).
2983 try!(self.parse_block())
2990 ExprClosure(capture_clause, decl, body), attrs))
2993 // `else` token already eaten
2994 pub fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
2995 if try!(self.eat_keyword(keywords::If) ){
2996 return self.parse_if_expr(None);
2998 let blk = try!(self.parse_block());
2999 return Ok(self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk), None));
3003 /// Parse a 'for' .. 'in' expression ('for' token already eaten)
3004 pub fn parse_for_expr(&mut self, opt_ident: Option<ast::Ident>,
3006 attrs: ThinAttributes) -> PResult<'a, P<Expr>> {
3007 // Parse: `for <src_pat> in <src_expr> <src_loop_block>`
3009 let pat = try!(self.parse_pat());
3010 try!(self.expect_keyword(keywords::In));
3011 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
3012 let (iattrs, loop_block) = try!(self.parse_inner_attrs_and_block());
3013 let attrs = attrs.append(iattrs.into_thin_attrs());
3015 let hi = self.last_span.hi;
3017 Ok(self.mk_expr(span_lo, hi,
3018 ExprForLoop(pat, expr, loop_block, opt_ident),
3022 /// Parse a 'while' or 'while let' expression ('while' token already eaten)
3023 pub fn parse_while_expr(&mut self, opt_ident: Option<ast::Ident>,
3025 attrs: ThinAttributes) -> PResult<'a, P<Expr>> {
3026 if self.token.is_keyword(keywords::Let) {
3027 return self.parse_while_let_expr(opt_ident, span_lo, attrs);
3029 let cond = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
3030 let (iattrs, body) = try!(self.parse_inner_attrs_and_block());
3031 let attrs = attrs.append(iattrs.into_thin_attrs());
3032 let hi = body.span.hi;
3033 return Ok(self.mk_expr(span_lo, hi, ExprWhile(cond, body, opt_ident),
3037 /// Parse a 'while let' expression ('while' token already eaten)
3038 pub fn parse_while_let_expr(&mut self, opt_ident: Option<ast::Ident>,
3040 attrs: ThinAttributes) -> PResult<'a, P<Expr>> {
3041 try!(self.expect_keyword(keywords::Let));
3042 let pat = try!(self.parse_pat());
3043 try!(self.expect(&token::Eq));
3044 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
3045 let (iattrs, body) = try!(self.parse_inner_attrs_and_block());
3046 let attrs = attrs.append(iattrs.into_thin_attrs());
3047 let hi = body.span.hi;
3048 return Ok(self.mk_expr(span_lo, hi, ExprWhileLet(pat, expr, body, opt_ident), attrs));
3051 // parse `loop {...}`, `loop` token already eaten
3052 pub fn parse_loop_expr(&mut self, opt_ident: Option<ast::Ident>,
3054 attrs: ThinAttributes) -> PResult<'a, P<Expr>> {
3055 let (iattrs, body) = try!(self.parse_inner_attrs_and_block());
3056 let attrs = attrs.append(iattrs.into_thin_attrs());
3057 let hi = body.span.hi;
3058 Ok(self.mk_expr(span_lo, hi, ExprLoop(body, opt_ident), attrs))
3061 // `match` token already eaten
3062 fn parse_match_expr(&mut self, attrs: ThinAttributes) -> PResult<'a, P<Expr>> {
3063 let match_span = self.last_span;
3064 let lo = self.last_span.lo;
3065 let discriminant = try!(self.parse_expr_res(
3066 Restrictions::RESTRICTION_NO_STRUCT_LITERAL, None));
3067 if let Err(mut e) = self.commit_expr_expecting(&*discriminant,
3068 token::OpenDelim(token::Brace)) {
3069 if self.token == token::Token::Semi {
3070 e.span_note(match_span, "did you mean to remove this `match` keyword?");
3074 let attrs = attrs.append(
3075 try!(self.parse_inner_attributes()).into_thin_attrs());
3076 let mut arms: Vec<Arm> = Vec::new();
3077 while self.token != token::CloseDelim(token::Brace) {
3078 arms.push(try!(self.parse_arm()));
3080 let hi = self.span.hi;
3082 return Ok(self.mk_expr(lo, hi, ExprMatch(discriminant, arms), attrs));
3085 pub fn parse_arm(&mut self) -> PResult<'a, Arm> {
3086 maybe_whole!(no_clone self, NtArm);
3088 let attrs = try!(self.parse_outer_attributes());
3089 let pats = try!(self.parse_pats());
3090 let mut guard = None;
3091 if try!(self.eat_keyword(keywords::If) ){
3092 guard = Some(try!(self.parse_expr()));
3094 try!(self.expect(&token::FatArrow));
3095 let expr = try!(self.parse_expr_res(Restrictions::RESTRICTION_STMT_EXPR, None));
3098 !classify::expr_is_simple_block(&*expr)
3099 && self.token != token::CloseDelim(token::Brace);
3102 try!(self.commit_expr(&*expr, &[token::Comma], &[token::CloseDelim(token::Brace)]));
3104 try!(self.eat(&token::Comma));
3115 /// Parse an expression
3116 pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
3117 self.parse_expr_res(Restrictions::empty(), None)
3120 /// Evaluate the closure with restrictions in place.
3122 /// After the closure is evaluated, restrictions are reset.
3123 pub fn with_res<F>(&mut self, r: Restrictions, f: F) -> PResult<'a, P<Expr>>
3124 where F: FnOnce(&mut Self) -> PResult<'a, P<Expr>>
3126 let old = self.restrictions;
3127 self.restrictions = r;
3129 self.restrictions = old;
3134 /// Parse an expression, subject to the given restrictions
3135 pub fn parse_expr_res(&mut self, r: Restrictions,
3136 already_parsed_attrs: Option<ThinAttributes>)
3137 -> PResult<'a, P<Expr>> {
3138 self.with_res(r, |this| this.parse_assoc_expr(already_parsed_attrs))
3141 /// Parse the RHS of a local variable declaration (e.g. '= 14;')
3142 fn parse_initializer(&mut self) -> PResult<'a, Option<P<Expr>>> {
3143 if self.check(&token::Eq) {
3145 Ok(Some(try!(self.parse_expr())))
3151 /// Parse patterns, separated by '|' s
3152 fn parse_pats(&mut self) -> PResult<'a, Vec<P<Pat>>> {
3153 let mut pats = Vec::new();
3155 pats.push(try!(self.parse_pat()));
3156 if self.check(&token::BinOp(token::Or)) { try!(self.bump());}
3157 else { return Ok(pats); }
3161 fn parse_pat_tuple_elements(&mut self) -> PResult<'a, Vec<P<Pat>>> {
3162 let mut fields = vec![];
3163 if !self.check(&token::CloseDelim(token::Paren)) {
3164 fields.push(try!(self.parse_pat()));
3165 if self.look_ahead(1, |t| *t != token::CloseDelim(token::Paren)) {
3166 while try!(self.eat(&token::Comma)) &&
3167 !self.check(&token::CloseDelim(token::Paren)) {
3168 fields.push(try!(self.parse_pat()));
3171 if fields.len() == 1 {
3172 try!(self.expect(&token::Comma));
3178 fn parse_pat_vec_elements(
3180 ) -> PResult<'a, (Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>)> {
3181 let mut before = Vec::new();
3182 let mut slice = None;
3183 let mut after = Vec::new();
3184 let mut first = true;
3185 let mut before_slice = true;
3187 while self.token != token::CloseDelim(token::Bracket) {
3191 try!(self.expect(&token::Comma));
3193 if self.token == token::CloseDelim(token::Bracket)
3194 && (before_slice || !after.is_empty()) {
3200 if self.check(&token::DotDot) {
3203 if self.check(&token::Comma) ||
3204 self.check(&token::CloseDelim(token::Bracket)) {
3205 slice = Some(P(ast::Pat {
3206 id: ast::DUMMY_NODE_ID,
3210 before_slice = false;
3216 let subpat = try!(self.parse_pat());
3217 if before_slice && self.check(&token::DotDot) {
3219 slice = Some(subpat);
3220 before_slice = false;
3221 } else if before_slice {
3222 before.push(subpat);
3228 Ok((before, slice, after))
3231 /// Parse the fields of a struct-like pattern
3232 fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<codemap::Spanned<ast::FieldPat>> , bool)> {
3233 let mut fields = Vec::new();
3234 let mut etc = false;
3235 let mut first = true;
3236 while self.token != token::CloseDelim(token::Brace) {
3240 try!(self.expect(&token::Comma));
3241 // accept trailing commas
3242 if self.check(&token::CloseDelim(token::Brace)) { break }
3245 let lo = self.span.lo;
3248 if self.check(&token::DotDot) {
3250 if self.token != token::CloseDelim(token::Brace) {
3251 let token_str = self.this_token_to_string();
3252 return Err(self.fatal(&format!("expected `{}`, found `{}`", "}",
3259 // Check if a colon exists one ahead. This means we're parsing a fieldname.
3260 let (subpat, fieldname, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
3261 // Parsing a pattern of the form "fieldname: pat"
3262 let fieldname = try!(self.parse_ident());
3264 let pat = try!(self.parse_pat());
3266 (pat, fieldname, false)
3268 // Parsing a pattern of the form "(box) (ref) (mut) fieldname"
3269 let is_box = try!(self.eat_keyword(keywords::Box));
3270 let boxed_span_lo = self.span.lo;
3271 let is_ref = try!(self.eat_keyword(keywords::Ref));
3272 let is_mut = try!(self.eat_keyword(keywords::Mut));
3273 let fieldname = try!(self.parse_ident());
3274 hi = self.last_span.hi;
3276 let bind_type = match (is_ref, is_mut) {
3277 (true, true) => BindingMode::ByRef(MutMutable),
3278 (true, false) => BindingMode::ByRef(MutImmutable),
3279 (false, true) => BindingMode::ByValue(MutMutable),
3280 (false, false) => BindingMode::ByValue(MutImmutable),
3282 let fieldpath = codemap::Spanned{span:self.last_span, node:fieldname};
3283 let fieldpat = P(ast::Pat{
3284 id: ast::DUMMY_NODE_ID,
3285 node: PatIdent(bind_type, fieldpath, None),
3286 span: mk_sp(boxed_span_lo, hi),
3289 let subpat = if is_box {
3291 id: ast::DUMMY_NODE_ID,
3292 node: PatBox(fieldpat),
3293 span: mk_sp(lo, hi),
3298 (subpat, fieldname, true)
3301 fields.push(codemap::Spanned { span: mk_sp(lo, hi),
3302 node: ast::FieldPat { ident: fieldname,
3304 is_shorthand: is_shorthand }});
3306 return Ok((fields, etc));
3309 fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
3310 if self.is_path_start() {
3311 let lo = self.span.lo;
3312 let (qself, path) = if try!(self.eat_lt()) {
3313 // Parse a qualified path
3315 try!(self.parse_qualified_path(NoTypesAllowed));
3318 // Parse an unqualified path
3319 (None, try!(self.parse_path(LifetimeAndTypesWithColons)))
3321 let hi = self.last_span.hi;
3322 Ok(self.mk_expr(lo, hi, ExprPath(qself, path), None))
3324 self.parse_pat_literal_maybe_minus()
3328 fn is_path_start(&self) -> bool {
3329 (self.token == token::Lt || self.token == token::ModSep
3330 || self.token.is_ident() || self.token.is_path())
3331 && !self.token.is_keyword(keywords::True) && !self.token.is_keyword(keywords::False)
3334 /// Parse a pattern.
3335 pub fn parse_pat(&mut self) -> PResult<'a, P<Pat>> {
3336 maybe_whole!(self, NtPat);
3338 let lo = self.span.lo;
3341 token::Underscore => {
3346 token::BinOp(token::And) | token::AndAnd => {
3347 // Parse &pat / &mut pat
3348 try!(self.expect_and());
3349 let mutbl = try!(self.parse_mutability());
3350 if let token::Lifetime(ident) = self.token {
3351 return Err(self.fatal(&format!("unexpected lifetime `{}` in pattern", ident)));
3354 let subpat = try!(self.parse_pat());
3355 pat = PatRegion(subpat, mutbl);
3357 token::OpenDelim(token::Paren) => {
3358 // Parse (pat,pat,pat,...) as tuple pattern
3360 let fields = try!(self.parse_pat_tuple_elements());
3361 try!(self.expect(&token::CloseDelim(token::Paren)));
3362 pat = PatTup(fields);
3364 token::OpenDelim(token::Bracket) => {
3365 // Parse [pat,pat,...] as slice pattern
3367 let (before, slice, after) = try!(self.parse_pat_vec_elements());
3368 try!(self.expect(&token::CloseDelim(token::Bracket)));
3369 pat = PatVec(before, slice, after);
3372 // At this point, token != _, &, &&, (, [
3373 if try!(self.eat_keyword(keywords::Mut)) {
3374 // Parse mut ident @ pat
3375 pat = try!(self.parse_pat_ident(BindingMode::ByValue(MutMutable)));
3376 } else if try!(self.eat_keyword(keywords::Ref)) {
3377 // Parse ref ident @ pat / ref mut ident @ pat
3378 let mutbl = try!(self.parse_mutability());
3379 pat = try!(self.parse_pat_ident(BindingMode::ByRef(mutbl)));
3380 } else if try!(self.eat_keyword(keywords::Box)) {
3382 let subpat = try!(self.parse_pat());
3383 pat = PatBox(subpat);
3384 } else if self.is_path_start() {
3385 // Parse pattern starting with a path
3386 if self.token.is_plain_ident() && self.look_ahead(1, |t| *t != token::DotDotDot &&
3387 *t != token::OpenDelim(token::Brace) &&
3388 *t != token::OpenDelim(token::Paren) &&
3389 // Contrary to its definition, a plain ident can be followed by :: in macros
3390 *t != token::ModSep) {
3391 // Plain idents have some extra abilities here compared to general paths
3392 if self.look_ahead(1, |t| *t == token::Not) {
3393 // Parse macro invocation
3394 let ident = try!(self.parse_ident());
3395 let ident_span = self.last_span;
3396 let path = ident_to_path(ident_span, ident);
3398 let delim = try!(self.expect_open_delim());
3399 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
3400 seq_sep_none(), |p| p.parse_token_tree()));
3401 let mac = Mac_ { path: path, tts: tts, ctxt: EMPTY_CTXT };
3402 pat = PatMac(codemap::Spanned {node: mac,
3403 span: mk_sp(lo, self.last_span.hi)});
3405 // Parse ident @ pat
3406 // This can give false positives and parse nullary enums,
3407 // they are dealt with later in resolve
3408 pat = try!(self.parse_pat_ident(BindingMode::ByValue(MutImmutable)));
3411 let (qself, path) = if try!(self.eat_lt()) {
3412 // Parse a qualified path
3414 try!(self.parse_qualified_path(NoTypesAllowed));
3417 // Parse an unqualified path
3418 (None, try!(self.parse_path(LifetimeAndTypesWithColons)))
3421 token::DotDotDot => {
3423 let hi = self.last_span.hi;
3424 let begin = self.mk_expr(lo, hi, ExprPath(qself, path), None);
3426 let end = try!(self.parse_pat_range_end());
3427 pat = PatRange(begin, end);
3429 token::OpenDelim(token::Brace) => {
3430 if qself.is_some() {
3431 return Err(self.fatal("unexpected `{` after qualified path"));
3433 // Parse struct pattern
3435 let (fields, etc) = try!(self.parse_pat_fields());
3437 pat = PatStruct(path, fields, etc);
3439 token::OpenDelim(token::Paren) => {
3440 if qself.is_some() {
3441 return Err(self.fatal("unexpected `(` after qualified path"));
3443 // Parse tuple struct or enum pattern
3444 if self.look_ahead(1, |t| *t == token::DotDot) {
3445 // This is a "top constructor only" pat
3448 try!(self.expect(&token::CloseDelim(token::Paren)));
3449 pat = PatEnum(path, None);
3451 let args = try!(self.parse_enum_variant_seq(
3452 &token::OpenDelim(token::Paren),
3453 &token::CloseDelim(token::Paren),
3454 seq_sep_trailing_allowed(token::Comma),
3455 |p| p.parse_pat()));
3456 pat = PatEnum(path, Some(args));
3461 // Parse qualified path
3462 Some(qself) => PatQPath(qself, path),
3463 // Parse nullary enum
3464 None => PatEnum(path, Some(vec![]))
3470 // Try to parse everything else as literal with optional minus
3471 let begin = try!(self.parse_pat_literal_maybe_minus());
3472 if try!(self.eat(&token::DotDotDot)) {
3473 let end = try!(self.parse_pat_range_end());
3474 pat = PatRange(begin, end);
3476 pat = PatLit(begin);
3482 let hi = self.last_span.hi;
3484 id: ast::DUMMY_NODE_ID,
3486 span: mk_sp(lo, hi),
3490 /// Parse ident or ident @ pat
3491 /// used by the copy foo and ref foo patterns to give a good
3492 /// error message when parsing mistakes like ref foo(a,b)
3493 fn parse_pat_ident(&mut self,
3494 binding_mode: ast::BindingMode)
3495 -> PResult<'a, ast::Pat_> {
3496 if !self.token.is_plain_ident() {
3497 let span = self.span;
3498 let tok_str = self.this_token_to_string();
3499 return Err(self.span_fatal(span,
3500 &format!("expected identifier, found `{}`", tok_str)))
3502 let ident = try!(self.parse_ident());
3503 let last_span = self.last_span;
3504 let name = codemap::Spanned{span: last_span, node: ident};
3505 let sub = if try!(self.eat(&token::At) ){
3506 Some(try!(self.parse_pat()))
3511 // just to be friendly, if they write something like
3513 // we end up here with ( as the current token. This shortly
3514 // leads to a parse error. Note that if there is no explicit
3515 // binding mode then we do not end up here, because the lookahead
3516 // will direct us over to parse_enum_variant()
3517 if self.token == token::OpenDelim(token::Paren) {
3518 let last_span = self.last_span;
3519 return Err(self.span_fatal(
3521 "expected identifier, found enum pattern"))
3524 Ok(PatIdent(binding_mode, name, sub))
3527 /// Parse a local variable declaration
3528 fn parse_local(&mut self, attrs: ThinAttributes) -> PResult<'a, P<Local>> {
3529 let lo = self.span.lo;
3530 let pat = try!(self.parse_pat());
3533 if try!(self.eat(&token::Colon) ){
3534 ty = Some(try!(self.parse_ty_sum()));
3536 let init = try!(self.parse_initializer());
3541 id: ast::DUMMY_NODE_ID,
3542 span: mk_sp(lo, self.last_span.hi),
3547 /// Parse a "let" stmt
3548 fn parse_let(&mut self, attrs: ThinAttributes) -> PResult<'a, P<Decl>> {
3549 let lo = self.span.lo;
3550 let local = try!(self.parse_local(attrs));
3551 Ok(P(spanned(lo, self.last_span.hi, DeclLocal(local))))
3554 /// Parse a structure field
3555 fn parse_name_and_ty(&mut self, pr: Visibility,
3556 attrs: Vec<Attribute> ) -> PResult<'a, StructField> {
3558 Inherited => self.span.lo,
3559 Public => self.last_span.lo,
3561 if !self.token.is_plain_ident() {
3562 return Err(self.fatal("expected ident"));
3564 let name = try!(self.parse_ident());
3565 try!(self.expect(&token::Colon));
3566 let ty = try!(self.parse_ty_sum());
3567 Ok(spanned(lo, self.last_span.hi, ast::StructField_ {
3568 kind: NamedField(name, pr),
3569 id: ast::DUMMY_NODE_ID,
3575 /// Emit an expected item after attributes error.
3576 fn expected_item_err(&self, attrs: &[Attribute]) {
3577 let message = match attrs.last() {
3578 Some(&Attribute { node: ast::Attribute_ { is_sugared_doc: true, .. }, .. }) => {
3579 "expected item after doc comment"
3581 _ => "expected item after attributes",
3584 self.span_err(self.last_span, message);
3587 /// Parse a statement. may include decl.
3588 pub fn parse_stmt(&mut self) -> PResult<'a, Option<P<Stmt>>> {
3589 Ok(try!(self.parse_stmt_()).map(P))
3592 fn parse_stmt_(&mut self) -> PResult<'a, Option<Stmt>> {
3593 maybe_whole!(Some deref self, NtStmt);
3595 let attrs = try!(self.parse_outer_attributes());
3596 let lo = self.span.lo;
3598 Ok(Some(if self.check_keyword(keywords::Let) {
3599 try!(self.expect_keyword(keywords::Let));
3600 let decl = try!(self.parse_let(attrs.into_thin_attrs()));
3601 let hi = decl.span.hi;
3602 let stmt = StmtDecl(decl, ast::DUMMY_NODE_ID);
3603 spanned(lo, hi, stmt)
3604 } else if self.token.is_ident()
3605 && !self.token.is_any_keyword()
3606 && self.look_ahead(1, |t| *t == token::Not) {
3607 // it's a macro invocation:
3609 // Potential trouble: if we allow macros with paths instead of
3610 // idents, we'd need to look ahead past the whole path here...
3611 let pth = try!(self.parse_path(NoTypesAllowed));
3614 let id = match self.token {
3615 token::OpenDelim(_) => token::special_idents::invalid, // no special identifier
3616 _ => try!(self.parse_ident()),
3619 // check that we're pointing at delimiters (need to check
3620 // again after the `if`, because of `parse_ident`
3621 // consuming more tokens).
3622 let delim = match self.token {
3623 token::OpenDelim(delim) => delim,
3625 // we only expect an ident if we didn't parse one
3627 let ident_str = if id.name == token::special_idents::invalid.name {
3632 let tok_str = self.this_token_to_string();
3633 return Err(self.fatal(&format!("expected {}`(` or `{{`, found `{}`",
3639 let tts = try!(self.parse_unspanned_seq(
3640 &token::OpenDelim(delim),
3641 &token::CloseDelim(delim),
3643 |p| p.parse_token_tree()
3645 let hi = self.last_span.hi;
3647 let style = if delim == token::Brace {
3650 MacStmtWithoutBraces
3653 if id.name == token::special_idents::invalid.name {
3654 let stmt = StmtMac(P(spanned(lo,
3656 Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT })),
3658 attrs.into_thin_attrs());
3659 spanned(lo, hi, stmt)
3661 // if it has a special ident, it's definitely an item
3663 // Require a semicolon or braces.
3664 if style != MacStmtWithBraces {
3665 if !try!(self.eat(&token::Semi) ){
3666 let last_span = self.last_span;
3667 self.span_err(last_span,
3668 "macros that expand to items must \
3669 either be surrounded with braces or \
3670 followed by a semicolon");
3673 spanned(lo, hi, StmtDecl(
3674 P(spanned(lo, hi, DeclItem(
3676 lo, hi, id /*id is good here*/,
3677 ItemMac(spanned(lo, hi,
3678 Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT })),
3679 Inherited, attrs)))),
3680 ast::DUMMY_NODE_ID))
3683 // FIXME: Bad copy of attrs
3684 match try!(self.parse_item_(attrs.clone(), false, true)) {
3687 let decl = P(spanned(lo, hi, DeclItem(i)));
3688 spanned(lo, hi, StmtDecl(decl, ast::DUMMY_NODE_ID))
3691 let unused_attrs = |attrs: &[_], s: &mut Self| {
3692 if attrs.len() > 0 {
3694 "expected statement after outer attribute");
3698 // Do not attempt to parse an expression if we're done here.
3699 if self.token == token::Semi {
3700 unused_attrs(&attrs, self);
3705 if self.token == token::CloseDelim(token::Brace) {
3706 unused_attrs(&attrs, self);
3710 // Remainder are line-expr stmts.
3711 let e = try!(self.parse_expr_res(
3712 Restrictions::RESTRICTION_STMT_EXPR, Some(attrs.into_thin_attrs())));
3714 let stmt = StmtExpr(e, ast::DUMMY_NODE_ID);
3715 spanned(lo, hi, stmt)
3721 /// Is this expression a successfully-parsed statement?
3722 fn expr_is_complete(&mut self, e: &Expr) -> bool {
3723 self.restrictions.contains(Restrictions::RESTRICTION_STMT_EXPR) &&
3724 !classify::expr_requires_semi_to_be_stmt(e)
3727 /// Parse a block. No inner attrs are allowed.
3728 pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
3729 maybe_whole!(no_clone self, NtBlock);
3731 let lo = self.span.lo;
3733 if !try!(self.eat(&token::OpenDelim(token::Brace)) ){
3735 let tok = self.this_token_to_string();
3736 return Err(self.span_fatal_help(sp,
3737 &format!("expected `{{`, found `{}`", tok),
3738 "place this code inside a block"));
3741 self.parse_block_tail(lo, DefaultBlock)
3744 /// Parse a block. Inner attrs are allowed.
3745 fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
3746 maybe_whole!(pair_empty self, NtBlock);
3748 let lo = self.span.lo;
3749 try!(self.expect(&token::OpenDelim(token::Brace)));
3750 Ok((try!(self.parse_inner_attributes()),
3751 try!(self.parse_block_tail(lo, DefaultBlock))))
3754 /// Parse the rest of a block expression or function body
3755 /// Precondition: already parsed the '{'.
3756 fn parse_block_tail(&mut self, lo: BytePos, s: BlockCheckMode) -> PResult<'a, P<Block>> {
3757 let mut stmts = vec![];
3758 let mut expr = None;
3760 while !try!(self.eat(&token::CloseDelim(token::Brace))) {
3761 let Spanned {node, span} = if let Some(s) = try!(self.parse_stmt_()) {
3764 // Found only `;` or `}`.
3769 try!(self.handle_expression_like_statement(e, span, &mut stmts, &mut expr));
3771 StmtMac(mac, MacStmtWithoutBraces, attrs) => {
3772 // statement macro without braces; might be an
3773 // expr depending on whether a semicolon follows
3776 stmts.push(P(Spanned {
3777 node: StmtMac(mac, MacStmtWithSemicolon, attrs),
3778 span: mk_sp(span.lo, self.span.hi),
3783 let e = self.mk_mac_expr(span.lo, span.hi,
3784 mac.and_then(|m| m.node),
3786 let e = try!(self.parse_dot_or_call_expr_with(e, attrs));
3787 let e = try!(self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e)));
3788 try!(self.handle_expression_like_statement(
3796 StmtMac(m, style, attrs) => {
3797 // statement macro; might be an expr
3800 stmts.push(P(Spanned {
3801 node: StmtMac(m, MacStmtWithSemicolon, attrs),
3802 span: mk_sp(span.lo, self.span.hi),
3806 token::CloseDelim(token::Brace) => {
3807 // if a block ends in `m!(arg)` without
3808 // a `;`, it must be an expr
3809 expr = Some(self.mk_mac_expr(span.lo, span.hi,
3810 m.and_then(|x| x.node),
3814 stmts.push(P(Spanned {
3815 node: StmtMac(m, style, attrs),
3821 _ => { // all other kinds of statements:
3822 let mut hi = span.hi;
3823 if classify::stmt_ends_with_semi(&node) {
3824 try!(self.commit_stmt_expecting(token::Semi));
3825 hi = self.last_span.hi;
3828 stmts.push(P(Spanned {
3830 span: mk_sp(span.lo, hi)
3839 id: ast::DUMMY_NODE_ID,
3841 span: mk_sp(lo, self.last_span.hi),
3845 fn handle_expression_like_statement(
3849 stmts: &mut Vec<P<Stmt>>,
3850 last_block_expr: &mut Option<P<Expr>>) -> PResult<'a, ()> {
3851 // expression without semicolon
3852 if classify::expr_requires_semi_to_be_stmt(&*e) {
3853 // Just check for errors and recover; do not eat semicolon yet.
3854 try!(self.commit_stmt(&[],
3855 &[token::Semi, token::CloseDelim(token::Brace)]));
3861 let span_with_semi = Span {
3863 hi: self.last_span.hi,
3864 expn_id: span.expn_id,
3866 stmts.push(P(Spanned {
3867 node: StmtSemi(e, ast::DUMMY_NODE_ID),
3868 span: span_with_semi,
3871 token::CloseDelim(token::Brace) => *last_block_expr = Some(e),
3873 stmts.push(P(Spanned {
3874 node: StmtExpr(e, ast::DUMMY_NODE_ID),
3882 // Parses a sequence of bounds if a `:` is found,
3883 // otherwise returns empty list.
3884 fn parse_colon_then_ty_param_bounds(&mut self,
3885 mode: BoundParsingMode)
3886 -> PResult<'a, TyParamBounds>
3888 if !try!(self.eat(&token::Colon) ){
3891 self.parse_ty_param_bounds(mode)
3895 // matches bounds = ( boundseq )?
3896 // where boundseq = ( polybound + boundseq ) | polybound
3897 // and polybound = ( 'for' '<' 'region '>' )? bound
3898 // and bound = 'region | trait_ref
3899 fn parse_ty_param_bounds(&mut self,
3900 mode: BoundParsingMode)
3901 -> PResult<'a, TyParamBounds>
3903 let mut result = vec!();
3905 let question_span = self.span;
3906 let ate_question = try!(self.eat(&token::Question));
3908 token::Lifetime(lifetime) => {
3910 self.span_err(question_span,
3911 "`?` may only modify trait bounds, not lifetime bounds");
3913 result.push(RegionTyParamBound(ast::Lifetime {
3914 id: ast::DUMMY_NODE_ID,
3920 token::ModSep | token::Ident(..) => {
3921 let poly_trait_ref = try!(self.parse_poly_trait_ref());
3922 let modifier = if ate_question {
3923 if mode == BoundParsingMode::Modified {
3924 TraitBoundModifier::Maybe
3926 self.span_err(question_span,
3928 TraitBoundModifier::None
3931 TraitBoundModifier::None
3933 result.push(TraitTyParamBound(poly_trait_ref, modifier))
3938 if !try!(self.eat(&token::BinOp(token::Plus)) ){
3943 return Ok(P::from_vec(result));
3946 /// Matches typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?
3947 fn parse_ty_param(&mut self) -> PResult<'a, TyParam> {
3948 let span = self.span;
3949 let ident = try!(self.parse_ident());
3951 let bounds = try!(self.parse_colon_then_ty_param_bounds(BoundParsingMode::Modified));
3953 let default = if self.check(&token::Eq) {
3955 Some(try!(self.parse_ty_sum()))
3962 id: ast::DUMMY_NODE_ID,
3969 /// Parse a set of optional generic type parameter declarations. Where
3970 /// clauses are not parsed here, and must be added later via
3971 /// `parse_where_clause()`.
3973 /// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
3974 /// | ( < lifetimes , typaramseq ( , )? > )
3975 /// where typaramseq = ( typaram ) | ( typaram , typaramseq )
3976 pub fn parse_generics(&mut self) -> PResult<'a, ast::Generics> {
3977 maybe_whole!(self, NtGenerics);
3979 if try!(self.eat(&token::Lt) ){
3980 let lifetime_defs = try!(self.parse_lifetime_defs());
3981 let mut seen_default = false;
3982 let ty_params = try!(self.parse_seq_to_gt(Some(token::Comma), |p| {
3983 try!(p.forbid_lifetime());
3984 let ty_param = try!(p.parse_ty_param());
3985 if ty_param.default.is_some() {
3986 seen_default = true;
3987 } else if seen_default {
3988 let last_span = p.last_span;
3989 p.span_err(last_span,
3990 "type parameters with a default must be trailing");
3995 lifetimes: lifetime_defs,
3996 ty_params: ty_params,
3997 where_clause: WhereClause {
3998 id: ast::DUMMY_NODE_ID,
3999 predicates: Vec::new(),
4003 Ok(ast::Generics::default())
4007 fn parse_generic_values_after_lt(&mut self) -> PResult<'a, (Vec<ast::Lifetime>,
4009 Vec<P<TypeBinding>>)> {
4010 let span_lo = self.span.lo;
4011 let lifetimes = try!(self.parse_lifetimes(token::Comma));
4013 let missing_comma = !lifetimes.is_empty() &&
4014 !self.token.is_like_gt() &&
4016 .as_ref().map_or(true,
4017 |x| &**x != &token::Comma);
4021 let msg = format!("expected `,` or `>` after lifetime \
4023 self.this_token_to_string());
4024 let mut err = self.diagnostic().struct_span_err(self.span, &msg);
4026 let span_hi = self.span.hi;
4027 let span_hi = if self.parse_ty().is_ok() {
4033 let msg = format!("did you mean a single argument type &'a Type, \
4034 or did you mean the comma-separated arguments \
4036 err.span_note(mk_sp(span_lo, span_hi), &msg);
4039 self.abort_if_errors()
4042 // First parse types.
4043 let (types, returned) = try!(self.parse_seq_to_gt_or_return(
4046 try!(p.forbid_lifetime());
4047 if p.look_ahead(1, |t| t == &token::Eq) {
4050 Ok(Some(try!(p.parse_ty_sum())))
4055 // If we found the `>`, don't continue.
4057 return Ok((lifetimes, types.into_vec(), Vec::new()));
4060 // Then parse type bindings.
4061 let bindings = try!(self.parse_seq_to_gt(
4064 try!(p.forbid_lifetime());
4066 let ident = try!(p.parse_ident());
4067 let found_eq = try!(p.eat(&token::Eq));
4070 p.span_warn(span, "whoops, no =?");
4072 let ty = try!(p.parse_ty());
4073 let hi = ty.span.hi;
4074 let span = mk_sp(lo, hi);
4075 return Ok(P(TypeBinding{id: ast::DUMMY_NODE_ID,
4082 Ok((lifetimes, types.into_vec(), bindings.into_vec()))
4085 fn forbid_lifetime(&mut self) -> PResult<'a, ()> {
4086 if self.token.is_lifetime() {
4087 let span = self.span;
4088 return Err(self.span_fatal(span, "lifetime parameters must be declared \
4089 prior to type parameters"))
4094 /// Parses an optional `where` clause and places it in `generics`.
4097 /// where T : Trait<U, V> + 'b, 'a : 'b
4099 pub fn parse_where_clause(&mut self) -> PResult<'a, ast::WhereClause> {
4100 maybe_whole!(self, NtWhereClause);
4102 let mut where_clause = WhereClause {
4103 id: ast::DUMMY_NODE_ID,
4104 predicates: Vec::new(),
4107 if !try!(self.eat_keyword(keywords::Where)) {
4108 return Ok(where_clause);
4111 let mut parsed_something = false;
4113 let lo = self.span.lo;
4115 token::OpenDelim(token::Brace) => {
4119 token::Lifetime(..) => {
4120 let bounded_lifetime =
4121 try!(self.parse_lifetime());
4123 try!(self.eat(&token::Colon));
4126 try!(self.parse_lifetimes(token::BinOp(token::Plus)));
4128 let hi = self.last_span.hi;
4129 let span = mk_sp(lo, hi);
4131 where_clause.predicates.push(ast::WherePredicate::RegionPredicate(
4132 ast::WhereRegionPredicate {
4134 lifetime: bounded_lifetime,
4139 parsed_something = true;
4143 let bound_lifetimes = if try!(self.eat_keyword(keywords::For) ){
4144 // Higher ranked constraint.
4145 try!(self.expect(&token::Lt));
4146 let lifetime_defs = try!(self.parse_lifetime_defs());
4147 try!(self.expect_gt());
4153 let bounded_ty = try!(self.parse_ty());
4155 if try!(self.eat(&token::Colon) ){
4156 let bounds = try!(self.parse_ty_param_bounds(BoundParsingMode::Bare));
4157 let hi = self.last_span.hi;
4158 let span = mk_sp(lo, hi);
4160 if bounds.is_empty() {
4162 "each predicate in a `where` clause must have \
4163 at least one bound in it");
4166 where_clause.predicates.push(ast::WherePredicate::BoundPredicate(
4167 ast::WhereBoundPredicate {
4169 bound_lifetimes: bound_lifetimes,
4170 bounded_ty: bounded_ty,
4174 parsed_something = true;
4175 } else if try!(self.eat(&token::Eq) ){
4176 // let ty = try!(self.parse_ty());
4177 let hi = self.last_span.hi;
4178 let span = mk_sp(lo, hi);
4179 // where_clause.predicates.push(
4180 // ast::WherePredicate::EqPredicate(ast::WhereEqPredicate {
4181 // id: ast::DUMMY_NODE_ID,
4183 // path: panic!("NYI"), //bounded_ty,
4186 // parsed_something = true;
4189 "equality constraints are not yet supported \
4190 in where clauses (#20041)");
4192 let last_span = self.last_span;
4193 self.span_err(last_span,
4194 "unexpected token in `where` clause");
4199 if !try!(self.eat(&token::Comma) ){
4204 if !parsed_something {
4205 let last_span = self.last_span;
4206 self.span_err(last_span,
4207 "a `where` clause must have at least one predicate \
4214 fn parse_fn_args(&mut self, named_args: bool, allow_variadic: bool)
4215 -> PResult<'a, (Vec<Arg> , bool)> {
4217 let mut args: Vec<Option<Arg>> =
4218 try!(self.parse_unspanned_seq(
4219 &token::OpenDelim(token::Paren),
4220 &token::CloseDelim(token::Paren),
4221 seq_sep_trailing_allowed(token::Comma),
4223 if p.token == token::DotDotDot {
4226 if p.token != token::CloseDelim(token::Paren) {
4228 return Err(p.span_fatal(span,
4229 "`...` must be last in argument list for variadic function"))
4233 return Err(p.span_fatal(span,
4234 "only foreign functions are allowed to be variadic"))
4238 Ok(Some(try!(p.parse_arg_general(named_args))))
4243 let variadic = match args.pop() {
4246 // Need to put back that last arg
4253 if variadic && args.is_empty() {
4255 "variadic function must be declared with at least one named argument");
4258 let args = args.into_iter().map(|x| x.unwrap()).collect();
4260 Ok((args, variadic))
4263 /// Parse the argument list and result type of a function declaration
4264 pub fn parse_fn_decl(&mut self, allow_variadic: bool) -> PResult<'a, P<FnDecl>> {
4266 let (args, variadic) = try!(self.parse_fn_args(true, allow_variadic));
4267 let ret_ty = try!(self.parse_ret_ty());
4276 fn is_self_ident(&mut self) -> bool {
4278 token::Ident(id, token::Plain) => id.name == special_idents::self_.name,
4283 fn expect_self_ident(&mut self) -> PResult<'a, ast::Ident> {
4285 token::Ident(id, token::Plain) if id.name == special_idents::self_.name => {
4290 let token_str = self.this_token_to_string();
4291 return Err(self.fatal(&format!("expected `self`, found `{}`",
4297 fn is_self_type_ident(&mut self) -> bool {
4299 token::Ident(id, token::Plain) => id.name == special_idents::type_self.name,
4304 fn expect_self_type_ident(&mut self) -> PResult<'a, ast::Ident> {
4306 token::Ident(id, token::Plain) if id.name == special_idents::type_self.name => {
4311 let token_str = self.this_token_to_string();
4312 Err(self.fatal(&format!("expected `Self`, found `{}`",
4318 /// Parse the argument list and result type of a function
4319 /// that may have a self type.
4320 fn parse_fn_decl_with_self<F>(&mut self,
4321 parse_arg_fn: F) -> PResult<'a, (ExplicitSelf, P<FnDecl>)> where
4322 F: FnMut(&mut Parser<'a>) -> PResult<'a, Arg>,
4324 fn maybe_parse_borrowed_explicit_self<'b>(this: &mut Parser<'b>)
4325 -> PResult<'b, ast::ExplicitSelf_> {
4326 // The following things are possible to see here:
4331 // fn(&'lt mut self)
4333 // We already know that the current token is `&`.
4335 if this.look_ahead(1, |t| t.is_keyword(keywords::SelfValue)) {
4337 Ok(SelfRegion(None, MutImmutable, try!(this.expect_self_ident())))
4338 } else if this.look_ahead(1, |t| t.is_mutability()) &&
4339 this.look_ahead(2, |t| t.is_keyword(keywords::SelfValue)) {
4341 let mutability = try!(this.parse_mutability());
4342 Ok(SelfRegion(None, mutability, try!(this.expect_self_ident())))
4343 } else if this.look_ahead(1, |t| t.is_lifetime()) &&
4344 this.look_ahead(2, |t| t.is_keyword(keywords::SelfValue)) {
4346 let lifetime = try!(this.parse_lifetime());
4347 Ok(SelfRegion(Some(lifetime), MutImmutable, try!(this.expect_self_ident())))
4348 } else if this.look_ahead(1, |t| t.is_lifetime()) &&
4349 this.look_ahead(2, |t| t.is_mutability()) &&
4350 this.look_ahead(3, |t| t.is_keyword(keywords::SelfValue)) {
4352 let lifetime = try!(this.parse_lifetime());
4353 let mutability = try!(this.parse_mutability());
4354 Ok(SelfRegion(Some(lifetime), mutability, try!(this.expect_self_ident())))
4360 try!(self.expect(&token::OpenDelim(token::Paren)));
4362 // A bit of complexity and lookahead is needed here in order to be
4363 // backwards compatible.
4364 let lo = self.span.lo;
4365 let mut self_ident_lo = self.span.lo;
4366 let mut self_ident_hi = self.span.hi;
4368 let mut mutbl_self = MutImmutable;
4369 let explicit_self = match self.token {
4370 token::BinOp(token::And) => {
4371 let eself = try!(maybe_parse_borrowed_explicit_self(self));
4372 self_ident_lo = self.last_span.lo;
4373 self_ident_hi = self.last_span.hi;
4376 token::BinOp(token::Star) => {
4377 // Possibly "*self" or "*mut self" -- not supported. Try to avoid
4378 // emitting cryptic "unexpected token" errors.
4380 let _mutability = if self.token.is_mutability() {
4381 try!(self.parse_mutability())
4385 if self.is_self_ident() {
4386 let span = self.span;
4387 self.span_err(span, "cannot pass self by raw pointer");
4390 // error case, making bogus self ident:
4391 SelfValue(special_idents::self_)
4393 token::Ident(..) => {
4394 if self.is_self_ident() {
4395 let self_ident = try!(self.expect_self_ident());
4397 // Determine whether this is the fully explicit form, `self:
4399 if try!(self.eat(&token::Colon) ){
4400 SelfExplicit(try!(self.parse_ty_sum()), self_ident)
4402 SelfValue(self_ident)
4404 } else if self.token.is_mutability() &&
4405 self.look_ahead(1, |t| t.is_keyword(keywords::SelfValue)) {
4406 mutbl_self = try!(self.parse_mutability());
4407 let self_ident = try!(self.expect_self_ident());
4409 // Determine whether this is the fully explicit form,
4411 if try!(self.eat(&token::Colon) ){
4412 SelfExplicit(try!(self.parse_ty_sum()), self_ident)
4414 SelfValue(self_ident)
4423 let explicit_self_sp = mk_sp(self_ident_lo, self_ident_hi);
4425 // shared fall-through for the three cases below. borrowing prevents simply
4426 // writing this as a closure
4427 macro_rules! parse_remaining_arguments {
4430 // If we parsed a self type, expect a comma before the argument list.
4434 let sep = seq_sep_trailing_allowed(token::Comma);
4435 let mut fn_inputs = try!(self.parse_seq_to_before_end(
4436 &token::CloseDelim(token::Paren),
4440 fn_inputs.insert(0, Arg::new_self(explicit_self_sp, mutbl_self, $self_id));
4443 token::CloseDelim(token::Paren) => {
4444 vec!(Arg::new_self(explicit_self_sp, mutbl_self, $self_id))
4447 let token_str = self.this_token_to_string();
4448 return Err(self.fatal(&format!("expected `,` or `)`, found `{}`",
4455 let fn_inputs = match explicit_self {
4457 let sep = seq_sep_trailing_allowed(token::Comma);
4458 try!(self.parse_seq_to_before_end(&token::CloseDelim(token::Paren),
4461 SelfValue(id) => parse_remaining_arguments!(id),
4462 SelfRegion(_,_,id) => parse_remaining_arguments!(id),
4463 SelfExplicit(_,id) => parse_remaining_arguments!(id),
4467 try!(self.expect(&token::CloseDelim(token::Paren)));
4469 let hi = self.span.hi;
4471 let ret_ty = try!(self.parse_ret_ty());
4473 let fn_decl = P(FnDecl {
4479 Ok((spanned(lo, hi, explicit_self), fn_decl))
4482 // parse the |arg, arg| header on a lambda
4483 fn parse_fn_block_decl(&mut self) -> PResult<'a, P<FnDecl>> {
4484 let inputs_captures = {
4485 if try!(self.eat(&token::OrOr) ){
4488 try!(self.expect(&token::BinOp(token::Or)));
4489 try!(self.parse_obsolete_closure_kind());
4490 let args = try!(self.parse_seq_to_before_end(
4491 &token::BinOp(token::Or),
4492 seq_sep_trailing_allowed(token::Comma),
4493 |p| p.parse_fn_block_arg()
4499 let output = try!(self.parse_ret_ty());
4502 inputs: inputs_captures,
4508 /// Parse the name and optional generic types of a function header.
4509 fn parse_fn_header(&mut self) -> PResult<'a, (Ident, ast::Generics)> {
4510 let id = try!(self.parse_ident());
4511 let generics = try!(self.parse_generics());
4515 fn mk_item(&mut self, lo: BytePos, hi: BytePos, ident: Ident,
4516 node: Item_, vis: Visibility,
4517 attrs: Vec<Attribute>) -> P<Item> {
4521 id: ast::DUMMY_NODE_ID,
4528 /// Parse an item-position function declaration.
4529 fn parse_item_fn(&mut self,
4531 constness: Constness,
4533 -> PResult<'a, ItemInfo> {
4534 let (ident, mut generics) = try!(self.parse_fn_header());
4535 let decl = try!(self.parse_fn_decl(false));
4536 generics.where_clause = try!(self.parse_where_clause());
4537 let (inner_attrs, body) = try!(self.parse_inner_attrs_and_block());
4538 Ok((ident, ItemFn(decl, unsafety, constness, abi, generics, body), Some(inner_attrs)))
4541 /// true if we are looking at `const ID`, false for things like `const fn` etc
4542 pub fn is_const_item(&mut self) -> bool {
4543 self.token.is_keyword(keywords::Const) &&
4544 !self.look_ahead(1, |t| t.is_keyword(keywords::Fn)) &&
4545 !self.look_ahead(1, |t| t.is_keyword(keywords::Unsafe))
4548 /// parses all the "front matter" for a `fn` declaration, up to
4549 /// and including the `fn` keyword:
4553 /// - `const unsafe fn`
4556 pub fn parse_fn_front_matter(&mut self)
4557 -> PResult<'a, (ast::Constness, ast::Unsafety, abi::Abi)> {
4558 let is_const_fn = try!(self.eat_keyword(keywords::Const));
4559 let unsafety = try!(self.parse_unsafety());
4560 let (constness, unsafety, abi) = if is_const_fn {
4561 (Constness::Const, unsafety, abi::Rust)
4563 let abi = if try!(self.eat_keyword(keywords::Extern)) {
4564 try!(self.parse_opt_abi()).unwrap_or(abi::C)
4568 (Constness::NotConst, unsafety, abi)
4570 try!(self.expect_keyword(keywords::Fn));
4571 Ok((constness, unsafety, abi))
4574 /// Parse an impl item.
4575 pub fn parse_impl_item(&mut self) -> PResult<'a, P<ImplItem>> {
4576 maybe_whole!(no_clone self, NtImplItem);
4578 let mut attrs = try!(self.parse_outer_attributes());
4579 let lo = self.span.lo;
4580 let vis = try!(self.parse_visibility());
4581 let (name, node) = if try!(self.eat_keyword(keywords::Type)) {
4582 let name = try!(self.parse_ident());
4583 try!(self.expect(&token::Eq));
4584 let typ = try!(self.parse_ty_sum());
4585 try!(self.expect(&token::Semi));
4586 (name, ast::ImplItemKind::Type(typ))
4587 } else if self.is_const_item() {
4588 try!(self.expect_keyword(keywords::Const));
4589 let name = try!(self.parse_ident());
4590 try!(self.expect(&token::Colon));
4591 let typ = try!(self.parse_ty_sum());
4592 try!(self.expect(&token::Eq));
4593 let expr = try!(self.parse_expr());
4594 try!(self.commit_expr_expecting(&expr, token::Semi));
4595 (name, ast::ImplItemKind::Const(typ, expr))
4597 let (name, inner_attrs, node) = try!(self.parse_impl_method(vis));
4598 attrs.extend(inner_attrs);
4603 id: ast::DUMMY_NODE_ID,
4604 span: mk_sp(lo, self.last_span.hi),
4612 fn complain_if_pub_macro(&mut self, visa: Visibility, span: Span) {
4615 self.diagnostic().struct_span_err(span, "can't qualify macro invocation with `pub`")
4616 .fileline_help(span, "try adjusting the macro to put `pub` inside \
4624 /// Parse a method or a macro invocation in a trait impl.
4625 fn parse_impl_method(&mut self, vis: Visibility)
4626 -> PResult<'a, (Ident, Vec<ast::Attribute>, ast::ImplItemKind)> {
4627 // code copied from parse_macro_use_or_failure... abstraction!
4628 if !self.token.is_any_keyword()
4629 && self.look_ahead(1, |t| *t == token::Not)
4630 && (self.look_ahead(2, |t| *t == token::OpenDelim(token::Paren))
4631 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))) {
4634 let last_span = self.last_span;
4635 self.complain_if_pub_macro(vis, last_span);
4637 let lo = self.span.lo;
4638 let pth = try!(self.parse_path(NoTypesAllowed));
4639 try!(self.expect(&token::Not));
4641 // eat a matched-delimiter token tree:
4642 let delim = try!(self.expect_open_delim());
4643 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
4645 |p| p.parse_token_tree()));
4646 let m_ = Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT };
4647 let m: ast::Mac = codemap::Spanned { node: m_,
4649 self.last_span.hi) };
4650 if delim != token::Brace {
4651 try!(self.expect(&token::Semi))
4653 Ok((token::special_idents::invalid, vec![], ast::ImplItemKind::Macro(m)))
4655 let (constness, unsafety, abi) = try!(self.parse_fn_front_matter());
4656 let ident = try!(self.parse_ident());
4657 let mut generics = try!(self.parse_generics());
4658 let (explicit_self, decl) = try!(self.parse_fn_decl_with_self(|p| {
4661 generics.where_clause = try!(self.parse_where_clause());
4662 let (inner_attrs, body) = try!(self.parse_inner_attrs_and_block());
4663 Ok((ident, inner_attrs, ast::ImplItemKind::Method(ast::MethodSig {
4666 explicit_self: explicit_self,
4668 constness: constness,
4674 /// Parse trait Foo { ... }
4675 fn parse_item_trait(&mut self, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
4677 let ident = try!(self.parse_ident());
4678 let mut tps = try!(self.parse_generics());
4680 // Parse supertrait bounds.
4681 let bounds = try!(self.parse_colon_then_ty_param_bounds(BoundParsingMode::Bare));
4683 tps.where_clause = try!(self.parse_where_clause());
4685 let meths = try!(self.parse_trait_items());
4686 Ok((ident, ItemTrait(unsafety, tps, bounds, meths), None))
4689 /// Parses items implementations variants
4690 /// impl<T> Foo { ... }
4691 /// impl<T> ToString for &'static T { ... }
4692 /// impl Send for .. {}
4693 fn parse_item_impl(&mut self, unsafety: ast::Unsafety) -> PResult<'a, ItemInfo> {
4694 let impl_span = self.span;
4696 // First, parse type parameters if necessary.
4697 let mut generics = try!(self.parse_generics());
4699 // Special case: if the next identifier that follows is '(', don't
4700 // allow this to be parsed as a trait.
4701 let could_be_trait = self.token != token::OpenDelim(token::Paren);
4703 let neg_span = self.span;
4704 let polarity = if try!(self.eat(&token::Not) ){
4705 ast::ImplPolarity::Negative
4707 ast::ImplPolarity::Positive
4711 let mut ty = try!(self.parse_ty_sum());
4713 // Parse traits, if necessary.
4714 let opt_trait = if could_be_trait && try!(self.eat_keyword(keywords::For) ){
4715 // New-style trait. Reinterpret the type as a trait.
4717 TyPath(None, ref path) => {
4719 path: (*path).clone(),
4724 self.span_err(ty.span, "not a trait");
4730 ast::ImplPolarity::Negative => {
4731 // This is a negated type implementation
4732 // `impl !MyType {}`, which is not allowed.
4733 self.span_err(neg_span, "inherent implementation can't be negated");
4740 if opt_trait.is_some() && try!(self.eat(&token::DotDot) ){
4741 if generics.is_parameterized() {
4742 self.span_err(impl_span, "default trait implementations are not \
4743 allowed to have generics");
4746 try!(self.expect(&token::OpenDelim(token::Brace)));
4747 try!(self.expect(&token::CloseDelim(token::Brace)));
4748 Ok((ast_util::impl_pretty_name(&opt_trait, None),
4749 ItemDefaultImpl(unsafety, opt_trait.unwrap()), None))
4751 if opt_trait.is_some() {
4752 ty = try!(self.parse_ty_sum());
4754 generics.where_clause = try!(self.parse_where_clause());
4756 try!(self.expect(&token::OpenDelim(token::Brace)));
4757 let attrs = try!(self.parse_inner_attributes());
4759 let mut impl_items = vec![];
4760 while !try!(self.eat(&token::CloseDelim(token::Brace))) {
4761 impl_items.push(try!(self.parse_impl_item()));
4764 Ok((ast_util::impl_pretty_name(&opt_trait, Some(&*ty)),
4765 ItemImpl(unsafety, polarity, generics, opt_trait, ty, impl_items),
4770 /// Parse a::B<String,i32>
4771 fn parse_trait_ref(&mut self) -> PResult<'a, TraitRef> {
4773 path: try!(self.parse_path(LifetimeAndTypesWithoutColons)),
4774 ref_id: ast::DUMMY_NODE_ID,
4778 fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, Vec<ast::LifetimeDef>> {
4779 if try!(self.eat_keyword(keywords::For) ){
4780 try!(self.expect(&token::Lt));
4781 let lifetime_defs = try!(self.parse_lifetime_defs());
4782 try!(self.expect_gt());
4789 /// Parse for<'l> a::B<String,i32>
4790 fn parse_poly_trait_ref(&mut self) -> PResult<'a, PolyTraitRef> {
4791 let lo = self.span.lo;
4792 let lifetime_defs = try!(self.parse_late_bound_lifetime_defs());
4794 Ok(ast::PolyTraitRef {
4795 bound_lifetimes: lifetime_defs,
4796 trait_ref: try!(self.parse_trait_ref()),
4797 span: mk_sp(lo, self.last_span.hi),
4801 /// Parse struct Foo { ... }
4802 fn parse_item_struct(&mut self) -> PResult<'a, ItemInfo> {
4803 let class_name = try!(self.parse_ident());
4804 let mut generics = try!(self.parse_generics());
4806 // There is a special case worth noting here, as reported in issue #17904.
4807 // If we are parsing a tuple struct it is the case that the where clause
4808 // should follow the field list. Like so:
4810 // struct Foo<T>(T) where T: Copy;
4812 // If we are parsing a normal record-style struct it is the case
4813 // that the where clause comes before the body, and after the generics.
4814 // So if we look ahead and see a brace or a where-clause we begin
4815 // parsing a record style struct.
4817 // Otherwise if we look ahead and see a paren we parse a tuple-style
4820 let vdata = if self.token.is_keyword(keywords::Where) {
4821 generics.where_clause = try!(self.parse_where_clause());
4822 if try!(self.eat(&token::Semi)) {
4823 // If we see a: `struct Foo<T> where T: Copy;` style decl.
4824 VariantData::Unit(ast::DUMMY_NODE_ID)
4826 // If we see: `struct Foo<T> where T: Copy { ... }`
4827 VariantData::Struct(try!(self.parse_record_struct_body(ParsePub::Yes)),
4830 // No `where` so: `struct Foo<T>;`
4831 } else if try!(self.eat(&token::Semi) ){
4832 VariantData::Unit(ast::DUMMY_NODE_ID)
4833 // Record-style struct definition
4834 } else if self.token == token::OpenDelim(token::Brace) {
4835 VariantData::Struct(try!(self.parse_record_struct_body(ParsePub::Yes)),
4837 // Tuple-style struct definition with optional where-clause.
4838 } else if self.token == token::OpenDelim(token::Paren) {
4839 let body = VariantData::Tuple(try!(self.parse_tuple_struct_body(ParsePub::Yes)),
4840 ast::DUMMY_NODE_ID);
4841 generics.where_clause = try!(self.parse_where_clause());
4842 try!(self.expect(&token::Semi));
4845 let token_str = self.this_token_to_string();
4846 return Err(self.fatal(&format!("expected `where`, `{{`, `(`, or `;` after struct \
4847 name, found `{}`", token_str)))
4850 Ok((class_name, ItemStruct(vdata, generics), None))
4853 pub fn parse_record_struct_body(&mut self,
4854 parse_pub: ParsePub)
4855 -> PResult<'a, Vec<StructField>> {
4856 let mut fields = Vec::new();
4857 if try!(self.eat(&token::OpenDelim(token::Brace)) ){
4858 while self.token != token::CloseDelim(token::Brace) {
4859 fields.push(try!(self.parse_struct_decl_field(parse_pub)));
4864 let token_str = self.this_token_to_string();
4865 return Err(self.fatal(&format!("expected `where`, or `{{` after struct \
4873 pub fn parse_tuple_struct_body(&mut self,
4874 parse_pub: ParsePub)
4875 -> PResult<'a, Vec<StructField>> {
4876 // This is the case where we find `struct Foo<T>(T) where T: Copy;`
4877 // Unit like structs are handled in parse_item_struct function
4878 let fields = try!(self.parse_unspanned_seq(
4879 &token::OpenDelim(token::Paren),
4880 &token::CloseDelim(token::Paren),
4881 seq_sep_trailing_allowed(token::Comma),
4883 let attrs = try!(p.parse_outer_attributes());
4885 let struct_field_ = ast::StructField_ {
4886 kind: UnnamedField (
4887 if parse_pub == ParsePub::Yes {
4888 try!(p.parse_visibility())
4893 id: ast::DUMMY_NODE_ID,
4894 ty: try!(p.parse_ty_sum()),
4897 Ok(spanned(lo, p.span.hi, struct_field_))
4903 /// Parse a structure field declaration
4904 pub fn parse_single_struct_field(&mut self,
4906 attrs: Vec<Attribute> )
4907 -> PResult<'a, StructField> {
4908 let a_var = try!(self.parse_name_and_ty(vis, attrs));
4913 token::CloseDelim(token::Brace) => {}
4915 let span = self.span;
4916 let token_str = self.this_token_to_string();
4917 return Err(self.span_fatal_help(span,
4918 &format!("expected `,`, or `}}`, found `{}`",
4920 "struct fields should be separated by commas"))
4926 /// Parse an element of a struct definition
4927 fn parse_struct_decl_field(&mut self, parse_pub: ParsePub) -> PResult<'a, StructField> {
4929 let attrs = try!(self.parse_outer_attributes());
4931 if try!(self.eat_keyword(keywords::Pub) ){
4932 if parse_pub == ParsePub::No {
4933 let span = self.last_span;
4934 self.span_err(span, "`pub` is not allowed here");
4936 return self.parse_single_struct_field(Public, attrs);
4939 return self.parse_single_struct_field(Inherited, attrs);
4942 /// Parse visibility: PUB or nothing
4943 fn parse_visibility(&mut self) -> PResult<'a, Visibility> {
4944 if try!(self.eat_keyword(keywords::Pub)) { Ok(Public) }
4945 else { Ok(Inherited) }
4948 /// Given a termination token, parse all of the items in a module
4949 fn parse_mod_items(&mut self, term: &token::Token, inner_lo: BytePos) -> PResult<'a, Mod> {
4950 let mut items = vec![];
4951 while let Some(item) = try!(self.parse_item()) {
4955 if !try!(self.eat(term)) {
4956 let token_str = self.this_token_to_string();
4957 return Err(self.fatal(&format!("expected item, found `{}`", token_str)));
4960 let hi = if self.span == codemap::DUMMY_SP {
4967 inner: mk_sp(inner_lo, hi),
4972 fn parse_item_const(&mut self, m: Option<Mutability>) -> PResult<'a, ItemInfo> {
4973 let id = try!(self.parse_ident());
4974 try!(self.expect(&token::Colon));
4975 let ty = try!(self.parse_ty_sum());
4976 try!(self.expect(&token::Eq));
4977 let e = try!(self.parse_expr());
4978 try!(self.commit_expr_expecting(&*e, token::Semi));
4979 let item = match m {
4980 Some(m) => ItemStatic(ty, m, e),
4981 None => ItemConst(ty, e),
4983 Ok((id, item, None))
4986 /// Parse a `mod <foo> { ... }` or `mod <foo>;` item
4987 fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
4988 let id_span = self.span;
4989 let id = try!(self.parse_ident());
4990 if self.check(&token::Semi) {
4992 // This mod is in an external file. Let's go get it!
4993 let (m, attrs) = try!(self.eval_src_mod(id, outer_attrs, id_span));
4994 Ok((id, m, Some(attrs)))
4996 self.push_mod_path(id, outer_attrs);
4997 try!(self.expect(&token::OpenDelim(token::Brace)));
4998 let mod_inner_lo = self.span.lo;
4999 let old_owns_directory = self.owns_directory;
5000 self.owns_directory = true;
5001 let attrs = try!(self.parse_inner_attributes());
5002 let m = try!(self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo));
5003 self.owns_directory = old_owns_directory;
5004 self.pop_mod_path();
5005 Ok((id, ItemMod(m), Some(attrs)))
5009 fn push_mod_path(&mut self, id: Ident, attrs: &[Attribute]) {
5010 let default_path = self.id_to_interned_str(id);
5011 let file_path = match ::attr::first_attr_value_str_by_name(attrs, "path") {
5013 None => default_path,
5015 self.mod_path_stack.push(file_path)
5018 fn pop_mod_path(&mut self) {
5019 self.mod_path_stack.pop().unwrap();
5022 pub fn submod_path_from_attr(attrs: &[ast::Attribute], dir_path: &Path) -> Option<PathBuf> {
5023 ::attr::first_attr_value_str_by_name(attrs, "path").map(|d| dir_path.join(&*d))
5026 /// Returns either a path to a module, or .
5027 pub fn default_submod_path(id: ast::Ident, dir_path: &Path, codemap: &CodeMap) -> ModulePath
5029 let mod_name = id.to_string();
5030 let default_path_str = format!("{}.rs", mod_name);
5031 let secondary_path_str = format!("{}/mod.rs", mod_name);
5032 let default_path = dir_path.join(&default_path_str);
5033 let secondary_path = dir_path.join(&secondary_path_str);
5034 let default_exists = codemap.file_exists(&default_path);
5035 let secondary_exists = codemap.file_exists(&secondary_path);
5037 let result = match (default_exists, secondary_exists) {
5038 (true, false) => Ok(ModulePathSuccess { path: default_path, owns_directory: false }),
5039 (false, true) => Ok(ModulePathSuccess { path: secondary_path, owns_directory: true }),
5040 (false, false) => Err(ModulePathError {
5041 err_msg: format!("file not found for module `{}`", mod_name),
5042 help_msg: format!("name the file either {} or {} inside the directory {:?}",
5045 dir_path.display()),
5047 (true, true) => Err(ModulePathError {
5048 err_msg: format!("file for module `{}` found at both {} and {}",
5051 secondary_path_str),
5052 help_msg: "delete or rename one of them to remove the ambiguity".to_owned(),
5058 path_exists: default_exists || secondary_exists,
5063 fn submod_path(&mut self,
5065 outer_attrs: &[ast::Attribute],
5066 id_sp: Span) -> PResult<'a, ModulePathSuccess> {
5067 let mut prefix = PathBuf::from(&self.sess.codemap().span_to_filename(self.span));
5069 let mut dir_path = prefix;
5070 for part in &self.mod_path_stack {
5071 dir_path.push(&**part);
5074 if let Some(p) = Parser::submod_path_from_attr(outer_attrs, &dir_path) {
5075 return Ok(ModulePathSuccess { path: p, owns_directory: true });
5078 let paths = Parser::default_submod_path(id, &dir_path, self.sess.codemap());
5080 if !self.owns_directory {
5081 let mut err = self.diagnostic().struct_span_err(id_sp,
5082 "cannot declare a new module at this location");
5083 let this_module = match self.mod_path_stack.last() {
5084 Some(name) => name.to_string(),
5085 None => self.root_module_name.as_ref().unwrap().clone(),
5087 err.span_note(id_sp,
5088 &format!("maybe move this module `{0}` to its own directory \
5091 if paths.path_exists {
5092 err.span_note(id_sp,
5093 &format!("... or maybe `use` the module `{}` instead \
5094 of possibly redeclaring it",
5098 self.abort_if_errors();
5101 match paths.result {
5102 Ok(succ) => Ok(succ),
5103 Err(err) => Err(self.span_fatal_help(id_sp, &err.err_msg, &err.help_msg)),
5107 /// Read a module from a source file.
5108 fn eval_src_mod(&mut self,
5110 outer_attrs: &[ast::Attribute],
5112 -> PResult<'a, (ast::Item_, Vec<ast::Attribute> )> {
5113 let ModulePathSuccess { path, owns_directory } = try!(self.submod_path(id,
5117 self.eval_src_mod_from_path(path,
5123 fn eval_src_mod_from_path(&mut self,
5125 owns_directory: bool,
5127 id_sp: Span) -> PResult<'a, (ast::Item_, Vec<ast::Attribute> )> {
5128 let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
5129 match included_mod_stack.iter().position(|p| *p == path) {
5131 let mut err = String::from("circular modules: ");
5132 let len = included_mod_stack.len();
5133 for p in &included_mod_stack[i.. len] {
5134 err.push_str(&p.to_string_lossy());
5135 err.push_str(" -> ");
5137 err.push_str(&path.to_string_lossy());
5138 return Err(self.span_fatal(id_sp, &err[..]));
5142 included_mod_stack.push(path.clone());
5143 drop(included_mod_stack);
5145 let mut p0 = new_sub_parser_from_file(self.sess,
5151 let mod_inner_lo = p0.span.lo;
5152 let mod_attrs = try!(p0.parse_inner_attributes());
5153 let m0 = try!(p0.parse_mod_items(&token::Eof, mod_inner_lo));
5154 self.sess.included_mod_stack.borrow_mut().pop();
5155 Ok((ast::ItemMod(m0), mod_attrs))
5158 /// Parse a function declaration from a foreign module
5159 fn parse_item_foreign_fn(&mut self, vis: ast::Visibility, lo: BytePos,
5160 attrs: Vec<Attribute>) -> PResult<'a, P<ForeignItem>> {
5161 try!(self.expect_keyword(keywords::Fn));
5163 let (ident, mut generics) = try!(self.parse_fn_header());
5164 let decl = try!(self.parse_fn_decl(true));
5165 generics.where_clause = try!(self.parse_where_clause());
5166 let hi = self.span.hi;
5167 try!(self.expect(&token::Semi));
5168 Ok(P(ast::ForeignItem {
5171 node: ForeignItemFn(decl, generics),
5172 id: ast::DUMMY_NODE_ID,
5173 span: mk_sp(lo, hi),
5178 /// Parse a static item from a foreign module
5179 fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: BytePos,
5180 attrs: Vec<Attribute>) -> PResult<'a, P<ForeignItem>> {
5181 try!(self.expect_keyword(keywords::Static));
5182 let mutbl = try!(self.eat_keyword(keywords::Mut));
5184 let ident = try!(self.parse_ident());
5185 try!(self.expect(&token::Colon));
5186 let ty = try!(self.parse_ty_sum());
5187 let hi = self.span.hi;
5188 try!(self.expect(&token::Semi));
5192 node: ForeignItemStatic(ty, mutbl),
5193 id: ast::DUMMY_NODE_ID,
5194 span: mk_sp(lo, hi),
5199 /// Parse extern crate links
5203 /// extern crate foo;
5204 /// extern crate bar as foo;
5205 fn parse_item_extern_crate(&mut self,
5207 visibility: Visibility,
5208 attrs: Vec<Attribute>)
5209 -> PResult<'a, P<Item>> {
5211 let crate_name = try!(self.parse_ident());
5212 let (maybe_path, ident) = if let Some(ident) = try!(self.parse_rename()) {
5213 (Some(crate_name.name), ident)
5217 try!(self.expect(&token::Semi));
5219 let last_span = self.last_span;
5221 if visibility == ast::Public {
5222 self.span_warn(mk_sp(lo, last_span.hi),
5223 "`pub extern crate` does not work as expected and should not be used. \
5224 Likely to become an error. Prefer `extern crate` and `pub use`.");
5230 ItemExternCrate(maybe_path),
5235 /// Parse `extern` for foreign ABIs
5238 /// `extern` is expected to have been
5239 /// consumed before calling this method
5245 fn parse_item_foreign_mod(&mut self,
5247 opt_abi: Option<abi::Abi>,
5248 visibility: Visibility,
5249 mut attrs: Vec<Attribute>)
5250 -> PResult<'a, P<Item>> {
5251 try!(self.expect(&token::OpenDelim(token::Brace)));
5253 let abi = opt_abi.unwrap_or(abi::C);
5255 attrs.extend(try!(self.parse_inner_attributes()));
5257 let mut foreign_items = vec![];
5258 while let Some(item) = try!(self.parse_foreign_item()) {
5259 foreign_items.push(item);
5261 try!(self.expect(&token::CloseDelim(token::Brace)));
5263 let last_span = self.last_span;
5264 let m = ast::ForeignMod {
5266 items: foreign_items
5270 special_idents::invalid,
5276 /// Parse type Foo = Bar;
5277 fn parse_item_type(&mut self) -> PResult<'a, ItemInfo> {
5278 let ident = try!(self.parse_ident());
5279 let mut tps = try!(self.parse_generics());
5280 tps.where_clause = try!(self.parse_where_clause());
5281 try!(self.expect(&token::Eq));
5282 let ty = try!(self.parse_ty_sum());
5283 try!(self.expect(&token::Semi));
5284 Ok((ident, ItemTy(ty, tps), None))
5287 /// Parse the part of an "enum" decl following the '{'
5288 fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> {
5289 let mut variants = Vec::new();
5290 let mut all_nullary = true;
5291 let mut any_disr = None;
5292 while self.token != token::CloseDelim(token::Brace) {
5293 let variant_attrs = try!(self.parse_outer_attributes());
5294 let vlo = self.span.lo;
5297 let mut disr_expr = None;
5298 let ident = try!(self.parse_ident());
5299 if self.check(&token::OpenDelim(token::Brace)) {
5300 // Parse a struct variant.
5301 all_nullary = false;
5302 struct_def = VariantData::Struct(try!(self.parse_record_struct_body(ParsePub::No)),
5303 ast::DUMMY_NODE_ID);
5304 } else if self.check(&token::OpenDelim(token::Paren)) {
5305 all_nullary = false;
5306 struct_def = VariantData::Tuple(try!(self.parse_tuple_struct_body(ParsePub::No)),
5307 ast::DUMMY_NODE_ID);
5308 } else if try!(self.eat(&token::Eq) ){
5309 disr_expr = Some(try!(self.parse_expr()));
5310 any_disr = disr_expr.as_ref().map(|expr| expr.span);
5311 struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
5313 struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
5316 let vr = ast::Variant_ {
5318 attrs: variant_attrs,
5320 disr_expr: disr_expr,
5322 variants.push(P(spanned(vlo, self.last_span.hi, vr)));
5324 if !try!(self.eat(&token::Comma)) { break; }
5326 try!(self.expect(&token::CloseDelim(token::Brace)));
5328 Some(disr_span) if !all_nullary =>
5329 self.span_err(disr_span,
5330 "discriminator values can only be used with a c-like enum"),
5334 Ok(ast::EnumDef { variants: variants })
5337 /// Parse an "enum" declaration
5338 fn parse_item_enum(&mut self) -> PResult<'a, ItemInfo> {
5339 let id = try!(self.parse_ident());
5340 let mut generics = try!(self.parse_generics());
5341 generics.where_clause = try!(self.parse_where_clause());
5342 try!(self.expect(&token::OpenDelim(token::Brace)));
5344 let enum_definition = try!(self.parse_enum_def(&generics));
5345 Ok((id, ItemEnum(enum_definition, generics), None))
5348 /// Parses a string as an ABI spec on an extern type or module. Consumes
5349 /// the `extern` keyword, if one is found.
5350 fn parse_opt_abi(&mut self) -> PResult<'a, Option<abi::Abi>> {
5352 token::Literal(token::Str_(s), suf) | token::Literal(token::StrRaw(s, _), suf) => {
5354 self.expect_no_suffix(sp, "ABI spec", suf);
5356 match abi::lookup(&s.as_str()) {
5357 Some(abi) => Ok(Some(abi)),
5359 let last_span = self.last_span;
5362 &format!("invalid ABI: expected one of [{}], \
5364 abi::all_names().join(", "),
5375 /// Parse one of the items allowed by the flags.
5376 /// NB: this function no longer parses the items inside an
5378 fn parse_item_(&mut self, attrs: Vec<Attribute>,
5379 macros_allowed: bool, attributes_allowed: bool) -> PResult<'a, Option<P<Item>>> {
5380 let nt_item = match self.token {
5381 token::Interpolated(token::NtItem(ref item)) => {
5382 Some((**item).clone())
5389 let mut attrs = attrs;
5390 mem::swap(&mut item.attrs, &mut attrs);
5391 item.attrs.extend(attrs);
5392 return Ok(Some(P(item)));
5397 let lo = self.span.lo;
5399 let visibility = try!(self.parse_visibility());
5401 if try!(self.eat_keyword(keywords::Use) ){
5403 let item_ = ItemUse(try!(self.parse_view_path()));
5404 try!(self.expect(&token::Semi));
5406 let last_span = self.last_span;
5407 let item = self.mk_item(lo,
5409 token::special_idents::invalid,
5413 return Ok(Some(item));
5416 if try!(self.eat_keyword(keywords::Extern)) {
5417 if try!(self.eat_keyword(keywords::Crate)) {
5418 return Ok(Some(try!(self.parse_item_extern_crate(lo, visibility, attrs))));
5421 let opt_abi = try!(self.parse_opt_abi());
5423 if try!(self.eat_keyword(keywords::Fn) ){
5424 // EXTERN FUNCTION ITEM
5425 let abi = opt_abi.unwrap_or(abi::C);
5426 let (ident, item_, extra_attrs) =
5427 try!(self.parse_item_fn(Unsafety::Normal, Constness::NotConst, abi));
5428 let last_span = self.last_span;
5429 let item = self.mk_item(lo,
5434 maybe_append(attrs, extra_attrs));
5435 return Ok(Some(item));
5436 } else if self.check(&token::OpenDelim(token::Brace)) {
5437 return Ok(Some(try!(self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs))));
5440 try!(self.expect_one_of(&[], &[]));
5443 if try!(self.eat_keyword(keywords::Static) ){
5445 let m = if try!(self.eat_keyword(keywords::Mut)) {MutMutable} else {MutImmutable};
5446 let (ident, item_, extra_attrs) = try!(self.parse_item_const(Some(m)));
5447 let last_span = self.last_span;
5448 let item = self.mk_item(lo,
5453 maybe_append(attrs, extra_attrs));
5454 return Ok(Some(item));
5456 if try!(self.eat_keyword(keywords::Const) ){
5457 if self.check_keyword(keywords::Fn)
5458 || (self.check_keyword(keywords::Unsafe)
5459 && self.look_ahead(1, |t| t.is_keyword(keywords::Fn))) {
5460 // CONST FUNCTION ITEM
5461 let unsafety = if try!(self.eat_keyword(keywords::Unsafe) ){
5467 let (ident, item_, extra_attrs) =
5468 try!(self.parse_item_fn(unsafety, Constness::Const, abi::Rust));
5469 let last_span = self.last_span;
5470 let item = self.mk_item(lo,
5475 maybe_append(attrs, extra_attrs));
5476 return Ok(Some(item));
5480 if try!(self.eat_keyword(keywords::Mut) ){
5481 let last_span = self.last_span;
5482 self.diagnostic().struct_span_err(last_span, "const globals cannot be mutable")
5483 .fileline_help(last_span, "did you mean to declare a static?")
5486 let (ident, item_, extra_attrs) = try!(self.parse_item_const(None));
5487 let last_span = self.last_span;
5488 let item = self.mk_item(lo,
5493 maybe_append(attrs, extra_attrs));
5494 return Ok(Some(item));
5496 if self.check_keyword(keywords::Unsafe) &&
5497 self.look_ahead(1, |t| t.is_keyword(keywords::Trait))
5499 // UNSAFE TRAIT ITEM
5500 try!(self.expect_keyword(keywords::Unsafe));
5501 try!(self.expect_keyword(keywords::Trait));
5502 let (ident, item_, extra_attrs) =
5503 try!(self.parse_item_trait(ast::Unsafety::Unsafe));
5504 let last_span = self.last_span;
5505 let item = self.mk_item(lo,
5510 maybe_append(attrs, extra_attrs));
5511 return Ok(Some(item));
5513 if self.check_keyword(keywords::Unsafe) &&
5514 self.look_ahead(1, |t| t.is_keyword(keywords::Impl))
5517 try!(self.expect_keyword(keywords::Unsafe));
5518 try!(self.expect_keyword(keywords::Impl));
5519 let (ident, item_, extra_attrs) = try!(self.parse_item_impl(ast::Unsafety::Unsafe));
5520 let last_span = self.last_span;
5521 let item = self.mk_item(lo,
5526 maybe_append(attrs, extra_attrs));
5527 return Ok(Some(item));
5529 if self.check_keyword(keywords::Fn) {
5532 let (ident, item_, extra_attrs) =
5533 try!(self.parse_item_fn(Unsafety::Normal, Constness::NotConst, abi::Rust));
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 if self.check_keyword(keywords::Unsafe)
5544 && self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) {
5545 // UNSAFE FUNCTION ITEM
5547 let abi = if try!(self.eat_keyword(keywords::Extern) ){
5548 try!(self.parse_opt_abi()).unwrap_or(abi::C)
5552 try!(self.expect_keyword(keywords::Fn));
5553 let (ident, item_, extra_attrs) =
5554 try!(self.parse_item_fn(Unsafety::Unsafe, Constness::NotConst, abi));
5555 let last_span = self.last_span;
5556 let item = self.mk_item(lo,
5561 maybe_append(attrs, extra_attrs));
5562 return Ok(Some(item));
5564 if try!(self.eat_keyword(keywords::Mod) ){
5566 let (ident, item_, extra_attrs) =
5567 try!(self.parse_item_mod(&attrs[..]));
5568 let last_span = self.last_span;
5569 let item = self.mk_item(lo,
5574 maybe_append(attrs, extra_attrs));
5575 return Ok(Some(item));
5577 if try!(self.eat_keyword(keywords::Type) ){
5579 let (ident, item_, extra_attrs) = try!(self.parse_item_type());
5580 let last_span = self.last_span;
5581 let item = self.mk_item(lo,
5586 maybe_append(attrs, extra_attrs));
5587 return Ok(Some(item));
5589 if try!(self.eat_keyword(keywords::Enum) ){
5591 let (ident, item_, extra_attrs) = try!(self.parse_item_enum());
5592 let last_span = self.last_span;
5593 let item = self.mk_item(lo,
5598 maybe_append(attrs, extra_attrs));
5599 return Ok(Some(item));
5601 if try!(self.eat_keyword(keywords::Trait) ){
5603 let (ident, item_, extra_attrs) =
5604 try!(self.parse_item_trait(ast::Unsafety::Normal));
5605 let last_span = self.last_span;
5606 let item = self.mk_item(lo,
5611 maybe_append(attrs, extra_attrs));
5612 return Ok(Some(item));
5614 if try!(self.eat_keyword(keywords::Impl) ){
5616 let (ident, item_, extra_attrs) = try!(self.parse_item_impl(ast::Unsafety::Normal));
5617 let last_span = self.last_span;
5618 let item = self.mk_item(lo,
5623 maybe_append(attrs, extra_attrs));
5624 return Ok(Some(item));
5626 if try!(self.eat_keyword(keywords::Struct) ){
5628 let (ident, item_, extra_attrs) = try!(self.parse_item_struct());
5629 let last_span = self.last_span;
5630 let item = self.mk_item(lo,
5635 maybe_append(attrs, extra_attrs));
5636 return Ok(Some(item));
5638 self.parse_macro_use_or_failure(attrs,macros_allowed,attributes_allowed,lo,visibility)
5641 /// Parse a foreign item.
5642 fn parse_foreign_item(&mut self) -> PResult<'a, Option<P<ForeignItem>>> {
5643 let attrs = try!(self.parse_outer_attributes());
5644 let lo = self.span.lo;
5645 let visibility = try!(self.parse_visibility());
5647 if self.check_keyword(keywords::Static) {
5648 // FOREIGN STATIC ITEM
5649 return Ok(Some(try!(self.parse_item_foreign_static(visibility, lo, attrs))));
5651 if self.check_keyword(keywords::Fn) || self.check_keyword(keywords::Unsafe) {
5652 // FOREIGN FUNCTION ITEM
5653 return Ok(Some(try!(self.parse_item_foreign_fn(visibility, lo, attrs))));
5656 // FIXME #5668: this will occur for a macro invocation:
5657 match try!(self.parse_macro_use_or_failure(attrs, true, false, lo, visibility)) {
5659 return Err(self.span_fatal(item.span, "macros cannot expand to foreign items"));
5665 /// This is the fall-through for parsing items.
5666 fn parse_macro_use_or_failure(
5668 attrs: Vec<Attribute> ,
5669 macros_allowed: bool,
5670 attributes_allowed: bool,
5672 visibility: Visibility
5673 ) -> PResult<'a, Option<P<Item>>> {
5674 if macros_allowed && !self.token.is_any_keyword()
5675 && self.look_ahead(1, |t| *t == token::Not)
5676 && (self.look_ahead(2, |t| t.is_plain_ident())
5677 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Paren))
5678 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))) {
5679 // MACRO INVOCATION ITEM
5681 let last_span = self.last_span;
5682 self.complain_if_pub_macro(visibility, last_span);
5684 let mac_lo = self.span.lo;
5687 let pth = try!(self.parse_path(NoTypesAllowed));
5688 try!(self.expect(&token::Not));
5690 // a 'special' identifier (like what `macro_rules!` uses)
5691 // is optional. We should eventually unify invoc syntax
5693 let id = if self.token.is_plain_ident() {
5694 try!(self.parse_ident())
5696 token::special_idents::invalid // no special identifier
5698 // eat a matched-delimiter token tree:
5699 let delim = try!(self.expect_open_delim());
5700 let tts = try!(self.parse_seq_to_end(&token::CloseDelim(delim),
5702 |p| p.parse_token_tree()));
5703 // single-variant-enum... :
5704 let m = Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT };
5705 let m: ast::Mac = codemap::Spanned { node: m,
5707 self.last_span.hi) };
5709 if delim != token::Brace {
5710 if !try!(self.eat(&token::Semi) ){
5711 let last_span = self.last_span;
5712 self.span_err(last_span,
5713 "macros that expand to items must either \
5714 be surrounded with braces or followed by \
5719 let item_ = ItemMac(m);
5720 let last_span = self.last_span;
5721 let item = self.mk_item(lo,
5727 return Ok(Some(item));
5730 // FAILURE TO PARSE ITEM
5734 let last_span = self.last_span;
5735 return Err(self.span_fatal(last_span, "unmatched visibility `pub`"));
5739 if !attributes_allowed && !attrs.is_empty() {
5740 self.expected_item_err(&attrs);
5745 pub fn parse_item(&mut self) -> PResult<'a, Option<P<Item>>> {
5746 let attrs = try!(self.parse_outer_attributes());
5747 self.parse_item_(attrs, true, false)
5751 /// Matches view_path : MOD? non_global_path as IDENT
5752 /// | MOD? non_global_path MOD_SEP LBRACE RBRACE
5753 /// | MOD? non_global_path MOD_SEP LBRACE ident_seq RBRACE
5754 /// | MOD? non_global_path MOD_SEP STAR
5755 /// | MOD? non_global_path
5756 fn parse_view_path(&mut self) -> PResult<'a, P<ViewPath>> {
5757 let lo = self.span.lo;
5759 // Allow a leading :: because the paths are absolute either way.
5760 // This occurs with "use $crate::..." in macros.
5761 try!(self.eat(&token::ModSep));
5763 if self.check(&token::OpenDelim(token::Brace)) {
5765 let idents = try!(self.parse_unspanned_seq(
5766 &token::OpenDelim(token::Brace),
5767 &token::CloseDelim(token::Brace),
5768 seq_sep_trailing_allowed(token::Comma),
5769 |p| p.parse_path_list_item()));
5770 let path = ast::Path {
5771 span: mk_sp(lo, self.span.hi),
5773 segments: Vec::new()
5775 return Ok(P(spanned(lo, self.span.hi, ViewPathList(path, idents))));
5778 let first_ident = try!(self.parse_ident());
5779 let mut path = vec!(first_ident);
5780 if let token::ModSep = self.token {
5781 // foo::bar or foo::{a,b,c} or foo::*
5782 while self.check(&token::ModSep) {
5786 token::Ident(..) => {
5787 let ident = try!(self.parse_ident());
5791 // foo::bar::{a,b,c}
5792 token::OpenDelim(token::Brace) => {
5793 let idents = try!(self.parse_unspanned_seq(
5794 &token::OpenDelim(token::Brace),
5795 &token::CloseDelim(token::Brace),
5796 seq_sep_trailing_allowed(token::Comma),
5797 |p| p.parse_path_list_item()
5799 let path = ast::Path {
5800 span: mk_sp(lo, self.span.hi),
5802 segments: path.into_iter().map(|identifier| {
5804 identifier: identifier,
5805 parameters: ast::PathParameters::none(),
5809 return Ok(P(spanned(lo, self.span.hi, ViewPathList(path, idents))));
5813 token::BinOp(token::Star) => {
5815 let path = ast::Path {
5816 span: mk_sp(lo, self.span.hi),
5818 segments: path.into_iter().map(|identifier| {
5820 identifier: identifier,
5821 parameters: ast::PathParameters::none(),
5825 return Ok(P(spanned(lo, self.span.hi, ViewPathGlob(path))));
5828 // fall-through for case foo::bar::;
5830 self.span_err(self.span, "expected identifier or `{` or `*`, found `;`");
5837 let mut rename_to = path[path.len() - 1];
5838 let path = ast::Path {
5839 span: mk_sp(lo, self.last_span.hi),
5841 segments: path.into_iter().map(|identifier| {
5843 identifier: identifier,
5844 parameters: ast::PathParameters::none(),
5848 rename_to = try!(self.parse_rename()).unwrap_or(rename_to);
5849 Ok(P(spanned(lo, self.last_span.hi, ViewPathSimple(rename_to, path))))
5852 fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
5853 if try!(self.eat_keyword(keywords::As)) {
5854 self.parse_ident().map(Some)
5860 /// Parses a source module as a crate. This is the main
5861 /// entry point for the parser.
5862 pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> {
5863 let lo = self.span.lo;
5865 attrs: try!(self.parse_inner_attributes()),
5866 module: try!(self.parse_mod_items(&token::Eof, lo)),
5867 config: self.cfg.clone(),
5868 span: mk_sp(lo, self.span.lo),
5869 exported_macros: Vec::new(),
5873 pub fn parse_optional_str(&mut self)
5874 -> PResult<'a, Option<(InternedString,
5876 Option<ast::Name>)>> {
5877 let ret = match self.token {
5878 token::Literal(token::Str_(s), suf) => {
5879 (self.id_to_interned_str(ast::Ident::with_empty_ctxt(s)), ast::CookedStr, suf)
5881 token::Literal(token::StrRaw(s, n), suf) => {
5882 (self.id_to_interned_str(ast::Ident::with_empty_ctxt(s)), ast::RawStr(n), suf)
5884 _ => return Ok(None)
5890 pub fn parse_str(&mut self) -> PResult<'a, (InternedString, StrStyle)> {
5891 match try!(self.parse_optional_str()) {
5892 Some((s, style, suf)) => {
5893 let sp = self.last_span;
5894 self.expect_no_suffix(sp, "string literal", suf);
5897 _ => Err(self.fatal("expected string literal"))