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::*;
12 use self::ItemOrViewItem::*;
15 use ast::{AssociatedType, BareFnTy};
16 use ast::{RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
17 use ast::{ProvidedMethod, Public, Unsafety};
18 use ast::{Mod, BiAdd, Arg, Arm, Attribute, BindByRef, BindByValue};
19 use ast::{BiBitAnd, BiBitOr, BiBitXor, BiRem, BiLt, BiGt, Block};
20 use ast::{BlockCheckMode, CaptureByRef, CaptureByValue, CaptureClause};
21 use ast::{Crate, CrateConfig, Decl, DeclItem};
22 use ast::{DeclLocal, DefaultBlock, UnDeref, BiDiv, EMPTY_CTXT, EnumDef, ExplicitSelf};
23 use ast::{Expr, Expr_, ExprAddrOf, ExprMatch, ExprAgain};
24 use ast::{ExprAssign, ExprAssignOp, ExprBinary, ExprBlock, ExprBox};
25 use ast::{ExprBreak, ExprCall, ExprCast};
26 use ast::{ExprField, ExprTupField, ExprClosure, ExprIf, ExprIfLet, ExprIndex};
27 use ast::{ExprLit, ExprLoop, ExprMac, ExprRange};
28 use ast::{ExprMethodCall, ExprParen, ExprPath, ExprQPath};
29 use ast::{ExprRepeat, ExprRet, ExprStruct, ExprTup, ExprUnary};
30 use ast::{ExprVec, ExprWhile, ExprWhileLet, ExprForLoop, Field, FnDecl};
31 use ast::{FnUnboxedClosureKind, FnMutUnboxedClosureKind};
32 use ast::{FnOnceUnboxedClosureKind};
33 use ast::{ForeignItem, ForeignItemStatic, ForeignItemFn, ForeignMod, FunctionRetTy};
34 use ast::{Ident, Inherited, ImplItem, Item, Item_, ItemStatic};
35 use ast::{ItemEnum, ItemFn, ItemForeignMod, ItemImpl, ItemConst};
36 use ast::{ItemMac, ItemMod, ItemStruct, ItemTrait, ItemTy};
37 use ast::{LifetimeDef, Lit, Lit_};
38 use ast::{LitBool, LitChar, LitByte, LitBinary};
39 use ast::{LitStr, LitInt, Local, LocalLet};
40 use ast::{MacStmtWithBraces, MacStmtWithSemicolon, MacStmtWithoutBraces};
41 use ast::{MutImmutable, MutMutable, Mac_, MacInvocTT, MatchSource};
42 use ast::{Method, MutTy, BiMul, Mutability};
43 use ast::{MethodImplItem, NamedField, UnNeg, NoReturn, NodeId, UnNot};
44 use ast::{Pat, PatEnum, PatIdent, PatLit, PatRange, PatRegion, PatStruct};
45 use ast::{PatTup, PatBox, PatWild, PatWildMulti, PatWildSingle};
46 use ast::{PolyTraitRef};
47 use ast::{QPath, RequiredMethod};
48 use ast::{Return, BiShl, BiShr, Stmt, StmtDecl};
49 use ast::{StmtExpr, StmtSemi, StmtMac, StructDef, StructField};
50 use ast::{StructVariantKind, BiSub, StrStyle};
51 use ast::{SelfExplicit, SelfRegion, SelfStatic, SelfValue};
52 use ast::{Delimited, SequenceRepetition, TokenTree, TraitItem, TraitRef};
53 use ast::{TtDelimited, TtSequence, TtToken};
54 use ast::{TupleVariantKind, Ty, Ty_, TypeBinding};
55 use ast::{TypeField, TyFixedLengthVec, TyBareFn};
56 use ast::{TyTypeof, TyInfer, TypeMethod};
57 use ast::{TyParam, TyParamBound, TyParen, TyPath, TyPolyTraitRef, TyPtr, TyQPath};
58 use ast::{TyRptr, TyTup, TyU32, TyVec, UnUniq};
59 use ast::{TypeImplItem, TypeTraitItem, Typedef, UnboxedClosureKind};
60 use ast::{UnnamedField, UnsafeBlock};
61 use ast::{ViewItem, ViewItem_, ViewItemExternCrate, ViewItemUse};
62 use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
63 use ast::{Visibility, WhereClause};
65 use ast_util::{self, as_prec, ident_to_path, operator_prec};
66 use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp};
68 use ext::tt::macro_parser;
70 use parse::attr::ParserAttr;
72 use parse::common::{SeqSep, seq_sep_none, seq_sep_trailing_allowed};
73 use parse::lexer::{Reader, TokenAndSpan};
74 use parse::obsolete::*;
75 use parse::token::{self, MatchNt, SubstNt, SpecialVarNt, InternedString};
76 use parse::token::{keywords, special_idents, SpecialMacroVar};
77 use parse::{new_sub_parser_from_file, ParseSess};
80 use owned_slice::OwnedSlice;
82 use std::collections::HashSet;
83 use std::io::fs::PathExtensions;
91 flags Restrictions: u8 {
92 const UNRESTRICTED = 0b0000,
93 const RESTRICTION_STMT_EXPR = 0b0001,
94 const RESTRICTION_NO_BAR_OP = 0b0010,
95 const RESTRICTION_NO_STRUCT_LITERAL = 0b0100,
96 const RESTRICTION_NO_DOTS = 0b1000,
101 type ItemInfo = (Ident, Item_, Option<Vec<Attribute> >);
103 /// How to parse a path. There are four different kinds of paths, all of which
104 /// are parsed somewhat differently.
105 #[derive(Copy, PartialEq)]
106 pub enum PathParsingMode {
107 /// A path with no type parameters; e.g. `foo::bar::Baz`
109 /// A path with a lifetime and type parameters, with no double colons
110 /// before the type parameters; e.g. `foo::bar<'a>::Baz<T>`
111 LifetimeAndTypesWithoutColons,
112 /// A path with a lifetime and type parameters with double colons before
113 /// the type parameters; e.g. `foo::bar::<'a>::Baz::<T>`
114 LifetimeAndTypesWithColons,
117 /// How to parse a bound, whether to allow bound modifiers such as `?`.
118 #[derive(Copy, PartialEq)]
119 pub enum BoundParsingMode {
124 enum ItemOrViewItem {
125 /// Indicates a failure to parse any kind of item. The attributes are
127 IoviNone(Vec<Attribute>),
129 IoviForeignItem(P<ForeignItem>),
130 IoviViewItem(ViewItem)
134 /// Possibly accept an `token::Interpolated` expression (a pre-parsed expression
135 /// dropped into the token stream, which happens while parsing the result of
136 /// macro expansion). Placement of these is not as complex as I feared it would
137 /// be. The important thing is to make sure that lookahead doesn't balk at
138 /// `token::Interpolated` tokens.
139 macro_rules! maybe_whole_expr {
142 let found = match $p.token {
143 token::Interpolated(token::NtExpr(ref e)) => {
146 token::Interpolated(token::NtPath(_)) => {
147 // FIXME: The following avoids an issue with lexical borrowck scopes,
148 // but the clone is unfortunate.
149 let pt = match $p.token {
150 token::Interpolated(token::NtPath(ref pt)) => (**pt).clone(),
154 Some($p.mk_expr(span.lo, span.hi, ExprPath(pt)))
156 token::Interpolated(token::NtBlock(_)) => {
157 // FIXME: The following avoids an issue with lexical borrowck scopes,
158 // but the clone is unfortunate.
159 let b = match $p.token {
160 token::Interpolated(token::NtBlock(ref b)) => (*b).clone(),
164 Some($p.mk_expr(span.lo, span.hi, ExprBlock(b)))
179 /// As maybe_whole_expr, but for things other than expressions
180 macro_rules! maybe_whole {
181 ($p:expr, $constructor:ident) => (
183 let found = match ($p).token {
184 token::Interpolated(token::$constructor(_)) => {
185 Some(($p).bump_and_get())
189 if let Some(token::Interpolated(token::$constructor(x))) = found {
194 (no_clone $p:expr, $constructor:ident) => (
196 let found = match ($p).token {
197 token::Interpolated(token::$constructor(_)) => {
198 Some(($p).bump_and_get())
202 if let Some(token::Interpolated(token::$constructor(x))) = found {
207 (deref $p:expr, $constructor:ident) => (
209 let found = match ($p).token {
210 token::Interpolated(token::$constructor(_)) => {
211 Some(($p).bump_and_get())
215 if let Some(token::Interpolated(token::$constructor(x))) = found {
220 (Some $p:expr, $constructor:ident) => (
222 let found = match ($p).token {
223 token::Interpolated(token::$constructor(_)) => {
224 Some(($p).bump_and_get())
228 if let Some(token::Interpolated(token::$constructor(x))) = found {
229 return Some(x.clone());
233 (iovi $p:expr, $constructor:ident) => (
235 let found = match ($p).token {
236 token::Interpolated(token::$constructor(_)) => {
237 Some(($p).bump_and_get())
241 if let Some(token::Interpolated(token::$constructor(x))) = found {
242 return IoviItem(x.clone());
246 (pair_empty $p:expr, $constructor:ident) => (
248 let found = match ($p).token {
249 token::Interpolated(token::$constructor(_)) => {
250 Some(($p).bump_and_get())
254 if let Some(token::Interpolated(token::$constructor(x))) = found {
255 return (Vec::new(), x);
262 fn maybe_append(mut lhs: Vec<Attribute>, rhs: Option<Vec<Attribute>>)
265 Some(ref attrs) => lhs.extend(attrs.iter().map(|a| a.clone())),
272 struct ParsedItemsAndViewItems {
273 attrs_remaining: Vec<Attribute>,
274 view_items: Vec<ViewItem>,
275 items: Vec<P<Item>> ,
276 foreign_items: Vec<P<ForeignItem>>
279 /* ident is handled by common.rs */
281 pub struct Parser<'a> {
282 pub sess: &'a ParseSess,
283 /// the current token:
284 pub token: token::Token,
285 /// the span of the current token:
287 /// the span of the prior token:
289 pub cfg: CrateConfig,
290 /// the previous token or None (only stashed sometimes).
291 pub last_token: Option<Box<token::Token>>,
292 pub buffer: [TokenAndSpan; 4],
293 pub buffer_start: int,
295 pub tokens_consumed: uint,
296 pub restrictions: Restrictions,
297 pub quote_depth: uint, // not (yet) related to the quasiquoter
298 pub reader: Box<Reader+'a>,
299 pub interner: Rc<token::IdentInterner>,
300 /// The set of seen errors about obsolete syntax. Used to suppress
301 /// extra detail when the same error is seen twice
302 pub obsolete_set: HashSet<ObsoleteSyntax>,
303 /// Used to determine the path to externally loaded source files
304 pub mod_path_stack: Vec<InternedString>,
305 /// Stack of spans of open delimiters. Used for error message.
306 pub open_braces: Vec<Span>,
307 /// Flag if this parser "owns" the directory that it is currently parsing
308 /// in. This will affect how nested files are looked up.
309 pub owns_directory: bool,
310 /// Name of the root module this parser originated from. If `None`, then the
311 /// name is not known. This does not change while the parser is descending
312 /// into modules, and sub-parsers have new values for this name.
313 pub root_module_name: Option<String>,
314 pub expected_tokens: Vec<TokenType>,
317 #[derive(PartialEq, Eq, Clone)]
324 fn to_string(&self) -> String {
326 TokenType::Token(ref t) => format!("`{}`", Parser::token_to_string(t)),
327 TokenType::Operator => "an operator".to_string(),
332 fn is_plain_ident_or_underscore(t: &token::Token) -> bool {
333 t.is_plain_ident() || *t == token::Underscore
336 impl<'a> Parser<'a> {
337 pub fn new(sess: &'a ParseSess,
338 cfg: ast::CrateConfig,
339 mut rdr: Box<Reader+'a>)
342 let tok0 = rdr.real_token();
344 let placeholder = TokenAndSpan {
345 tok: token::Underscore,
351 interner: token::get_ident_interner(),
367 restrictions: UNRESTRICTED,
369 obsolete_set: HashSet::new(),
370 mod_path_stack: Vec::new(),
371 open_braces: Vec::new(),
372 owns_directory: true,
373 root_module_name: None,
374 expected_tokens: Vec::new(),
378 /// Convert a token to a string using self's reader
379 pub fn token_to_string(token: &token::Token) -> String {
380 pprust::token_to_string(token)
383 /// Convert the current token to a string using self's reader
384 pub fn this_token_to_string(&mut self) -> String {
385 Parser::token_to_string(&self.token)
388 pub fn unexpected_last(&mut self, t: &token::Token) -> ! {
389 let token_str = Parser::token_to_string(t);
390 let last_span = self.last_span;
391 self.span_fatal(last_span, &format!("unexpected token: `{}`",
395 pub fn unexpected(&mut self) -> ! {
396 let this_token = self.this_token_to_string();
397 self.fatal(&format!("unexpected token: `{}`", this_token)[]);
400 /// Expect and consume the token t. Signal an error if
401 /// the next token is not t.
402 pub fn expect(&mut self, t: &token::Token) {
403 if self.expected_tokens.is_empty() {
404 if self.token == *t {
407 let token_str = Parser::token_to_string(t);
408 let this_token_str = self.this_token_to_string();
409 self.fatal(&format!("expected `{}`, found `{}`",
414 self.expect_one_of(slice::ref_slice(t), &[]);
418 /// Expect next token to be edible or inedible token. If edible,
419 /// then consume it; if inedible, then return without consuming
420 /// anything. Signal a fatal error if next token is unexpected.
421 pub fn expect_one_of(&mut self,
422 edible: &[token::Token],
423 inedible: &[token::Token]) {
424 fn tokens_to_string(tokens: &[TokenType]) -> String {
425 let mut i = tokens.iter();
426 // This might be a sign we need a connect method on Iterator.
428 .map_or("".to_string(), |t| t.to_string());
429 i.enumerate().fold(b, |mut b, (i, ref a)| {
430 if tokens.len() > 2 && i == tokens.len() - 2 {
432 } else if tokens.len() == 2 && i == tokens.len() - 2 {
437 b.push_str(&*a.to_string());
441 if edible.contains(&self.token) {
443 } else if inedible.contains(&self.token) {
444 // leave it in the input
446 let mut expected = edible.iter().map(|x| TokenType::Token(x.clone()))
447 .collect::<Vec<_>>();
448 expected.extend(inedible.iter().map(|x| TokenType::Token(x.clone())));
449 expected.push_all(&*self.expected_tokens);
450 expected.sort_by(|a, b| a.to_string().cmp(&b.to_string()));
452 let expect = tokens_to_string(&expected[]);
453 let actual = self.this_token_to_string();
455 &(if expected.len() != 1 {
456 (format!("expected one of {}, found `{}`",
460 (format!("expected {}, found `{}`",
468 /// Check for erroneous `ident { }`; if matches, signal error and
469 /// recover (without consuming any expected input token). Returns
470 /// true if and only if input was consumed for recovery.
471 pub fn check_for_erroneous_unit_struct_expecting(&mut self, expected: &[token::Token]) -> bool {
472 if self.token == token::OpenDelim(token::Brace)
473 && expected.iter().all(|t| *t != token::OpenDelim(token::Brace))
474 && self.look_ahead(1, |t| *t == token::CloseDelim(token::Brace)) {
475 // matched; signal non-fatal error and recover.
476 let span = self.span;
478 "unit-like struct construction is written with no trailing `{ }`");
479 self.eat(&token::OpenDelim(token::Brace));
480 self.eat(&token::CloseDelim(token::Brace));
487 /// Commit to parsing a complete expression `e` expected to be
488 /// followed by some token from the set edible + inedible. Recover
489 /// from anticipated input errors, discarding erroneous characters.
490 pub fn commit_expr(&mut self, e: &Expr, edible: &[token::Token], inedible: &[token::Token]) {
491 debug!("commit_expr {:?}", e);
492 if let ExprPath(..) = e.node {
493 // might be unit-struct construction; check for recoverableinput error.
494 let mut expected = edible.iter().map(|x| x.clone()).collect::<Vec<_>>();
495 expected.push_all(inedible);
496 self.check_for_erroneous_unit_struct_expecting(&expected[]);
498 self.expect_one_of(edible, inedible)
501 pub fn commit_expr_expecting(&mut self, e: &Expr, edible: token::Token) {
502 self.commit_expr(e, &[edible], &[])
505 /// Commit to parsing a complete statement `s`, which expects to be
506 /// followed by some token from the set edible + inedible. Check
507 /// for recoverable input errors, discarding erroneous characters.
508 pub fn commit_stmt(&mut self, edible: &[token::Token], inedible: &[token::Token]) {
511 .map_or(false, |t| t.is_ident() || t.is_path()) {
512 let mut expected = edible.iter().map(|x| x.clone()).collect::<Vec<_>>();
513 expected.push_all(&inedible[]);
514 self.check_for_erroneous_unit_struct_expecting(
517 self.expect_one_of(edible, inedible)
520 pub fn commit_stmt_expecting(&mut self, edible: token::Token) {
521 self.commit_stmt(&[edible], &[])
524 pub fn parse_ident(&mut self) -> ast::Ident {
525 self.check_strict_keywords();
526 self.check_reserved_keywords();
528 token::Ident(i, _) => {
532 token::Interpolated(token::NtIdent(..)) => {
533 self.bug("ident interpolation not converted to real token");
536 let token_str = self.this_token_to_string();
537 self.fatal(&format!("expected ident, found `{}`",
543 pub fn parse_path_list_item(&mut self) -> ast::PathListItem {
544 let lo = self.span.lo;
545 let node = if self.eat_keyword(keywords::Mod) {
546 let span = self.last_span;
547 self.span_warn(span, "deprecated syntax; use the `self` keyword now");
548 ast::PathListMod { id: ast::DUMMY_NODE_ID }
549 } else if self.eat_keyword(keywords::Self) {
550 ast::PathListMod { id: ast::DUMMY_NODE_ID }
552 let ident = self.parse_ident();
553 ast::PathListIdent { name: ident, id: ast::DUMMY_NODE_ID }
555 let hi = self.last_span.hi;
556 spanned(lo, hi, node)
559 /// Check if the next token is `tok`, and return `true` if so.
561 /// This method is will automatically add `tok` to `expected_tokens` if `tok` is not
563 pub fn check(&mut self, tok: &token::Token) -> bool {
564 let is_present = self.token == *tok;
565 if !is_present { self.expected_tokens.push(TokenType::Token(tok.clone())); }
569 /// Consume token 'tok' if it exists. Returns true if the given
570 /// token was present, false otherwise.
571 pub fn eat(&mut self, tok: &token::Token) -> bool {
572 let is_present = self.check(tok);
573 if is_present { self.bump() }
577 /// If the next token is the given keyword, eat it and return
578 /// true. Otherwise, return false.
579 pub fn eat_keyword(&mut self, kw: keywords::Keyword) -> bool {
580 if self.token.is_keyword(kw) {
588 /// If the given word is not a keyword, signal an error.
589 /// If the next token is not the given word, signal an error.
590 /// Otherwise, eat it.
591 pub fn expect_keyword(&mut self, kw: keywords::Keyword) {
592 if !self.eat_keyword(kw) {
593 let id_interned_str = token::get_name(kw.to_name());
594 let token_str = self.this_token_to_string();
595 self.fatal(&format!("expected `{}`, found `{}`",
596 id_interned_str, token_str)[])
600 /// Signal an error if the given string is a strict keyword
601 pub fn check_strict_keywords(&mut self) {
602 if self.token.is_strict_keyword() {
603 let token_str = self.this_token_to_string();
604 let span = self.span;
606 &format!("expected identifier, found keyword `{}`",
611 /// Signal an error if the current token is a reserved keyword
612 pub fn check_reserved_keywords(&mut self) {
613 if self.token.is_reserved_keyword() {
614 let token_str = self.this_token_to_string();
615 self.fatal(&format!("`{}` is a reserved keyword",
620 /// Expect and consume an `&`. If `&&` is seen, replace it with a single
621 /// `&` and continue. If an `&` is not seen, signal an error.
622 fn expect_and(&mut self) {
624 token::BinOp(token::And) => self.bump(),
626 let span = self.span;
627 let lo = span.lo + BytePos(1);
628 self.replace_token(token::BinOp(token::And), lo, span.hi)
631 let token_str = self.this_token_to_string();
633 Parser::token_to_string(&token::BinOp(token::And));
634 self.fatal(&format!("expected `{}`, found `{}`",
641 /// Expect and consume a `|`. If `||` is seen, replace it with a single
642 /// `|` and continue. If a `|` is not seen, signal an error.
643 fn expect_or(&mut self) {
645 token::BinOp(token::Or) => self.bump(),
647 let span = self.span;
648 let lo = span.lo + BytePos(1);
649 self.replace_token(token::BinOp(token::Or), lo, span.hi)
652 let found_token = self.this_token_to_string();
654 Parser::token_to_string(&token::BinOp(token::Or));
655 self.fatal(&format!("expected `{}`, found `{}`",
662 pub fn expect_no_suffix(&mut self, sp: Span, kind: &str, suffix: Option<ast::Name>) {
664 None => {/* everything ok */}
666 let text = suf.as_str();
668 self.span_bug(sp, "found empty literal suffix in Some")
670 self.span_err(sp, &*format!("{} with a suffix is illegal", kind));
676 /// Attempt to consume a `<`. If `<<` is seen, replace it with a single
677 /// `<` and continue. If a `<` is not seen, return false.
679 /// This is meant to be used when parsing generics on a path to get the
681 fn eat_lt(&mut self) -> bool {
683 token::Lt => { self.bump(); true }
684 token::BinOp(token::Shl) => {
685 let span = self.span;
686 let lo = span.lo + BytePos(1);
687 self.replace_token(token::Lt, lo, span.hi);
694 fn expect_lt(&mut self) {
696 let found_token = self.this_token_to_string();
697 let token_str = Parser::token_to_string(&token::Lt);
698 self.fatal(&format!("expected `{}`, found `{}`",
704 /// Parse a sequence bracketed by `|` and `|`, stopping before the `|`.
705 fn parse_seq_to_before_or<T, F>(&mut self,
709 F: FnMut(&mut Parser) -> T,
711 let mut first = true;
712 let mut vector = Vec::new();
713 while self.token != token::BinOp(token::Or) &&
714 self.token != token::OrOr {
726 /// Expect and consume a GT. if a >> is seen, replace it
727 /// with a single > and continue. If a GT is not seen,
729 pub fn expect_gt(&mut self) {
731 token::Gt => self.bump(),
732 token::BinOp(token::Shr) => {
733 let span = self.span;
734 let lo = span.lo + BytePos(1);
735 self.replace_token(token::Gt, lo, span.hi)
737 token::BinOpEq(token::Shr) => {
738 let span = self.span;
739 let lo = span.lo + BytePos(1);
740 self.replace_token(token::Ge, lo, span.hi)
743 let span = self.span;
744 let lo = span.lo + BytePos(1);
745 self.replace_token(token::Eq, lo, span.hi)
748 let gt_str = Parser::token_to_string(&token::Gt);
749 let this_token_str = self.this_token_to_string();
750 self.fatal(&format!("expected `{}`, found `{}`",
757 pub fn parse_seq_to_before_gt_or_return<T, F>(&mut self,
758 sep: Option<token::Token>,
760 -> (OwnedSlice<T>, bool) where
761 F: FnMut(&mut Parser) -> Option<T>,
763 let mut v = Vec::new();
764 // This loop works by alternating back and forth between parsing types
765 // and commas. For example, given a string `A, B,>`, the parser would
766 // first parse `A`, then a comma, then `B`, then a comma. After that it
767 // would encounter a `>` and stop. This lets the parser handle trailing
768 // commas in generic parameters, because it can stop either after
769 // parsing a type or after parsing a comma.
770 for i in iter::count(0u, 1) {
771 if self.check(&token::Gt)
772 || self.token == token::BinOp(token::Shr)
773 || self.token == token::Ge
774 || self.token == token::BinOpEq(token::Shr) {
780 Some(result) => v.push(result),
781 None => return (OwnedSlice::from_vec(v), true)
784 sep.as_ref().map(|t| self.expect(t));
787 return (OwnedSlice::from_vec(v), false);
790 /// Parse a sequence bracketed by '<' and '>', stopping
792 pub fn parse_seq_to_before_gt<T, F>(&mut self,
793 sep: Option<token::Token>,
795 -> OwnedSlice<T> where
796 F: FnMut(&mut Parser) -> T,
798 let (result, returned) = self.parse_seq_to_before_gt_or_return(sep, |p| Some(f(p)));
803 pub fn parse_seq_to_gt<T, F>(&mut self,
804 sep: Option<token::Token>,
806 -> OwnedSlice<T> where
807 F: FnMut(&mut Parser) -> T,
809 let v = self.parse_seq_to_before_gt(sep, f);
814 pub fn parse_seq_to_gt_or_return<T, F>(&mut self,
815 sep: Option<token::Token>,
817 -> (OwnedSlice<T>, bool) where
818 F: FnMut(&mut Parser) -> Option<T>,
820 let (v, returned) = self.parse_seq_to_before_gt_or_return(sep, f);
824 return (v, returned);
827 /// Parse a sequence, including the closing delimiter. The function
828 /// f must consume tokens until reaching the next separator or
830 pub fn parse_seq_to_end<T, F>(&mut self,
835 F: FnMut(&mut Parser) -> T,
837 let val = self.parse_seq_to_before_end(ket, sep, f);
842 /// Parse a sequence, not including the closing delimiter. The function
843 /// f must consume tokens until reaching the next separator or
845 pub fn parse_seq_to_before_end<T, F>(&mut self,
850 F: FnMut(&mut Parser) -> T,
852 let mut first: bool = true;
854 while self.token != *ket {
857 if first { first = false; }
858 else { self.expect(t); }
862 if sep.trailing_sep_allowed && self.check(ket) { break; }
868 /// Parse a sequence, including the closing delimiter. The function
869 /// f must consume tokens until reaching the next separator or
871 pub fn parse_unspanned_seq<T, F>(&mut self,
877 F: FnMut(&mut Parser) -> T,
880 let result = self.parse_seq_to_before_end(ket, sep, f);
885 /// Parse a sequence parameter of enum variant. For consistency purposes,
886 /// these should not be empty.
887 pub fn parse_enum_variant_seq<T, F>(&mut self,
893 F: FnMut(&mut Parser) -> T,
895 let result = self.parse_unspanned_seq(bra, ket, sep, f);
896 if result.is_empty() {
897 let last_span = self.last_span;
898 self.span_err(last_span,
899 "nullary enum variants are written with no trailing `( )`");
904 // NB: Do not use this function unless you actually plan to place the
905 // spanned list in the AST.
906 pub fn parse_seq<T, F>(&mut self,
911 -> Spanned<Vec<T>> where
912 F: FnMut(&mut Parser) -> T,
914 let lo = self.span.lo;
916 let result = self.parse_seq_to_before_end(ket, sep, f);
917 let hi = self.span.hi;
919 spanned(lo, hi, result)
922 /// Advance the parser by one token
923 pub fn bump(&mut self) {
924 self.last_span = self.span;
925 // Stash token for error recovery (sometimes; clone is not necessarily cheap).
926 self.last_token = if self.token.is_ident() || self.token.is_path() {
927 Some(box self.token.clone())
931 let next = if self.buffer_start == self.buffer_end {
932 self.reader.real_token()
934 // Avoid token copies with `replace`.
935 let buffer_start = self.buffer_start as uint;
936 let next_index = (buffer_start + 1) & 3 as uint;
937 self.buffer_start = next_index as int;
939 let placeholder = TokenAndSpan {
940 tok: token::Underscore,
943 mem::replace(&mut self.buffer[buffer_start], placeholder)
946 self.token = next.tok;
947 self.tokens_consumed += 1u;
948 self.expected_tokens.clear();
949 // check after each token
950 self.check_unknown_macro_variable();
953 /// Advance the parser by one token and return the bumped token.
954 pub fn bump_and_get(&mut self) -> token::Token {
955 let old_token = mem::replace(&mut self.token, token::Underscore);
960 /// EFFECT: replace the current token and span with the given one
961 pub fn replace_token(&mut self,
965 self.last_span = mk_sp(self.span.lo, lo);
967 self.span = mk_sp(lo, hi);
969 pub fn buffer_length(&mut self) -> int {
970 if self.buffer_start <= self.buffer_end {
971 return self.buffer_end - self.buffer_start;
973 return (4 - self.buffer_start) + self.buffer_end;
975 pub fn look_ahead<R, F>(&mut self, distance: uint, f: F) -> R where
976 F: FnOnce(&token::Token) -> R,
978 let dist = distance as int;
979 while self.buffer_length() < dist {
980 self.buffer[self.buffer_end as uint] = self.reader.real_token();
981 self.buffer_end = (self.buffer_end + 1) & 3;
983 f(&self.buffer[((self.buffer_start + dist - 1) & 3) as uint].tok)
985 pub fn fatal(&mut self, m: &str) -> ! {
986 self.sess.span_diagnostic.span_fatal(self.span, m)
988 pub fn span_fatal(&mut self, sp: Span, m: &str) -> ! {
989 self.sess.span_diagnostic.span_fatal(sp, m)
991 pub fn span_fatal_help(&mut self, sp: Span, m: &str, help: &str) -> ! {
992 self.span_err(sp, m);
993 self.span_help(sp, help);
994 panic!(diagnostic::FatalError);
996 pub fn span_note(&mut self, sp: Span, m: &str) {
997 self.sess.span_diagnostic.span_note(sp, m)
999 pub fn span_help(&mut self, sp: Span, m: &str) {
1000 self.sess.span_diagnostic.span_help(sp, m)
1002 pub fn bug(&mut self, m: &str) -> ! {
1003 self.sess.span_diagnostic.span_bug(self.span, m)
1005 pub fn warn(&mut self, m: &str) {
1006 self.sess.span_diagnostic.span_warn(self.span, m)
1008 pub fn span_warn(&mut self, sp: Span, m: &str) {
1009 self.sess.span_diagnostic.span_warn(sp, m)
1011 pub fn span_err(&mut self, sp: Span, m: &str) {
1012 self.sess.span_diagnostic.span_err(sp, m)
1014 pub fn span_bug(&mut self, sp: Span, m: &str) -> ! {
1015 self.sess.span_diagnostic.span_bug(sp, m)
1017 pub fn abort_if_errors(&mut self) {
1018 self.sess.span_diagnostic.handler().abort_if_errors();
1021 pub fn id_to_interned_str(&mut self, id: Ident) -> InternedString {
1022 token::get_ident(id)
1025 /// Is the current token one of the keywords that signals a bare function
1027 pub fn token_is_bare_fn_keyword(&mut self) -> bool {
1028 self.token.is_keyword(keywords::Fn) ||
1029 self.token.is_keyword(keywords::Unsafe) ||
1030 self.token.is_keyword(keywords::Extern)
1033 /// Is the current token one of the keywords that signals a closure type?
1034 pub fn token_is_closure_keyword(&mut self) -> bool {
1035 self.token.is_keyword(keywords::Unsafe)
1038 pub fn get_lifetime(&mut self) -> ast::Ident {
1040 token::Lifetime(ref ident) => *ident,
1041 _ => self.bug("not a lifetime"),
1045 pub fn parse_for_in_type(&mut self) -> Ty_ {
1047 Parses whatever can come after a `for` keyword in a type.
1048 The `for` has already been consumed.
1052 - for <'lt> |S| -> T
1056 - for <'lt> [unsafe] [extern "ABI"] fn (S) -> T
1057 - for <'lt> path::foo(a, b)
1062 let lifetime_defs = self.parse_late_bound_lifetime_defs();
1064 // examine next token to decide to do
1065 if self.eat_keyword(keywords::Proc) {
1066 self.parse_proc_type(lifetime_defs)
1067 } else if self.token_is_bare_fn_keyword() || self.token_is_closure_keyword() {
1068 self.parse_ty_bare_fn_or_ty_closure(lifetime_defs)
1069 } else if self.check(&token::ModSep) ||
1070 self.token.is_ident() ||
1071 self.token.is_path()
1073 let trait_ref = self.parse_trait_ref();
1074 let poly_trait_ref = ast::PolyTraitRef { bound_lifetimes: lifetime_defs,
1075 trait_ref: trait_ref };
1076 let other_bounds = if self.eat(&token::BinOp(token::Plus)) {
1077 self.parse_ty_param_bounds(BoundParsingMode::Bare)
1082 Some(TraitTyParamBound(poly_trait_ref, TraitBoundModifier::None)).into_iter()
1083 .chain(other_bounds.into_vec().into_iter())
1085 ast::TyPolyTraitRef(all_bounds)
1087 self.parse_ty_closure(lifetime_defs)
1091 pub fn parse_ty_path(&mut self) -> Ty_ {
1092 let path = self.parse_path(LifetimeAndTypesWithoutColons);
1093 TyPath(path, ast::DUMMY_NODE_ID)
1096 /// parse a TyBareFn type:
1097 pub fn parse_ty_bare_fn(&mut self, lifetime_defs: Vec<ast::LifetimeDef>) -> Ty_ {
1100 [unsafe] [extern "ABI"] fn <'lt> (S) -> T
1101 ^~~~^ ^~~~^ ^~~~^ ^~^ ^
1104 | | | Argument types
1110 let unsafety = self.parse_unsafety();
1111 let abi = if self.eat_keyword(keywords::Extern) {
1112 self.parse_opt_abi().unwrap_or(abi::C)
1117 self.expect_keyword(keywords::Fn);
1118 let lifetime_defs = self.parse_legacy_lifetime_defs(lifetime_defs);
1119 let (inputs, variadic) = self.parse_fn_args(false, true);
1120 let ret_ty = self.parse_ret_ty();
1121 let decl = P(FnDecl {
1126 TyBareFn(P(BareFnTy {
1129 lifetimes: lifetime_defs,
1134 /// Parses a procedure type (`proc`). The initial `proc` keyword must
1135 /// already have been parsed.
1136 pub fn parse_proc_type(&mut self, lifetime_defs: Vec<ast::LifetimeDef>) -> Ty_ {
1139 proc <'lt> (S) [:Bounds] -> T
1140 ^~~^ ^~~~^ ^ ^~~~~~~~^ ^
1146 the `proc` keyword (already consumed)
1150 let proc_span = self.last_span;
1152 // To be helpful, parse the proc as ever
1153 let _ = self.parse_legacy_lifetime_defs(lifetime_defs);
1154 let _ = self.parse_fn_args(false, false);
1155 let _ = self.parse_colon_then_ty_param_bounds(BoundParsingMode::Bare);
1156 let _ = self.parse_ret_ty();
1158 self.obsolete(proc_span, ObsoleteSyntax::ProcType);
1163 /// Parses an optional unboxed closure kind (`&:`, `&mut:`, or `:`).
1164 pub fn parse_optional_unboxed_closure_kind(&mut self)
1165 -> Option<UnboxedClosureKind> {
1166 if self.check(&token::BinOp(token::And)) &&
1167 self.look_ahead(1, |t| t.is_keyword(keywords::Mut)) &&
1168 self.look_ahead(2, |t| *t == token::Colon) {
1172 return Some(FnMutUnboxedClosureKind)
1175 if self.token == token::BinOp(token::And) &&
1176 self.look_ahead(1, |t| *t == token::Colon) {
1179 return Some(FnUnboxedClosureKind)
1182 if self.eat(&token::Colon) {
1183 return Some(FnOnceUnboxedClosureKind)
1189 pub fn parse_ty_bare_fn_or_ty_closure(&mut self, lifetime_defs: Vec<LifetimeDef>) -> Ty_ {
1190 // Both bare fns and closures can begin with stuff like unsafe
1191 // and extern. So we just scan ahead a few tokens to see if we see
1194 // Closure: [unsafe] <'lt> |S| [:Bounds] -> T
1195 // Fn: [unsafe] [extern "ABI"] fn <'lt> (S) -> T
1197 if self.token.is_keyword(keywords::Fn) {
1198 self.parse_ty_bare_fn(lifetime_defs)
1199 } else if self.token.is_keyword(keywords::Extern) {
1200 self.parse_ty_bare_fn(lifetime_defs)
1201 } else if self.token.is_keyword(keywords::Unsafe) {
1202 if self.look_ahead(1, |t| t.is_keyword(keywords::Fn) ||
1203 t.is_keyword(keywords::Extern)) {
1204 self.parse_ty_bare_fn(lifetime_defs)
1206 self.parse_ty_closure(lifetime_defs)
1209 self.parse_ty_closure(lifetime_defs)
1213 /// Parse a TyClosure type
1214 pub fn parse_ty_closure(&mut self, lifetime_defs: Vec<ast::LifetimeDef>) -> Ty_ {
1217 [unsafe] <'lt> |S| [:Bounds] -> T
1218 ^~~~~~~^ ^~~~^ ^ ^~~~~~~~^ ^
1221 | | | Closure bounds
1223 | Deprecated lifetime defs
1229 let ty_closure_span = self.last_span;
1231 // To be helpful, parse the closure type as ever
1232 let _ = self.parse_unsafety();
1234 let _ = self.parse_legacy_lifetime_defs(lifetime_defs);
1236 if !self.eat(&token::OrOr) {
1239 let _ = self.parse_seq_to_before_or(
1241 |p| p.parse_arg_general(false));
1245 let _ = self.parse_colon_then_ty_param_bounds(BoundParsingMode::Bare);
1247 let _ = self.parse_ret_ty();
1249 self.obsolete(ty_closure_span, ObsoleteSyntax::ClosureType);
1254 pub fn parse_unsafety(&mut self) -> Unsafety {
1255 if self.eat_keyword(keywords::Unsafe) {
1256 return Unsafety::Unsafe;
1258 return Unsafety::Normal;
1262 /// Parses `[ 'for' '<' lifetime_defs '>' ]'
1263 fn parse_legacy_lifetime_defs(&mut self,
1264 lifetime_defs: Vec<ast::LifetimeDef>)
1265 -> Vec<ast::LifetimeDef>
1267 if self.token == token::Lt {
1269 if lifetime_defs.is_empty() {
1270 self.warn("deprecated syntax; use the `for` keyword now \
1271 (e.g. change `fn<'a>` to `for<'a> fn`)");
1272 let lifetime_defs = self.parse_lifetime_defs();
1276 self.fatal("cannot use new `for` keyword and older syntax together");
1283 /// Parses `type Foo;` in a trait declaration only. The `type` keyword has
1284 /// already been parsed.
1285 fn parse_associated_type(&mut self, attrs: Vec<Attribute>)
1288 let ty_param = self.parse_ty_param();
1289 self.expect(&token::Semi);
1296 /// Parses `type Foo = TYPE;` in an implementation declaration only. The
1297 /// `type` keyword has already been parsed.
1298 fn parse_typedef(&mut self, attrs: Vec<Attribute>, vis: Visibility)
1300 let lo = self.span.lo;
1301 let ident = self.parse_ident();
1302 self.expect(&token::Eq);
1303 let typ = self.parse_ty_sum();
1304 let hi = self.span.hi;
1305 self.expect(&token::Semi);
1307 id: ast::DUMMY_NODE_ID,
1308 span: mk_sp(lo, hi),
1316 /// Parse the items in a trait declaration
1317 pub fn parse_trait_items(&mut self) -> Vec<TraitItem> {
1318 self.parse_unspanned_seq(
1319 &token::OpenDelim(token::Brace),
1320 &token::CloseDelim(token::Brace),
1323 let attrs = p.parse_outer_attributes();
1325 if p.eat_keyword(keywords::Type) {
1326 TypeTraitItem(P(p.parse_associated_type(attrs)))
1330 let vis = p.parse_visibility();
1331 let style = p.parse_unsafety();
1332 let abi = if p.eat_keyword(keywords::Extern) {
1333 p.parse_opt_abi().unwrap_or(abi::C)
1337 p.expect_keyword(keywords::Fn);
1339 let ident = p.parse_ident();
1340 let mut generics = p.parse_generics();
1342 let (explicit_self, d) = p.parse_fn_decl_with_self(|p| {
1343 // This is somewhat dubious; We don't want to allow
1344 // argument names to be left off if there is a
1346 p.parse_arg_general(false)
1349 p.parse_where_clause(&mut generics);
1351 let hi = p.last_span.hi;
1355 debug!("parse_trait_methods(): parsing required method");
1356 RequiredMethod(TypeMethod {
1363 explicit_self: explicit_self,
1364 id: ast::DUMMY_NODE_ID,
1365 span: mk_sp(lo, hi),
1369 token::OpenDelim(token::Brace) => {
1370 debug!("parse_trait_methods(): parsing provided method");
1371 let (inner_attrs, body) =
1372 p.parse_inner_attrs_and_block();
1373 let mut attrs = attrs;
1374 attrs.push_all(&inner_attrs[]);
1375 ProvidedMethod(P(ast::Method {
1377 id: ast::DUMMY_NODE_ID,
1378 span: mk_sp(lo, hi),
1379 node: ast::MethDecl(ident,
1391 let token_str = p.this_token_to_string();
1392 p.fatal(&format!("expected `;` or `{{`, found `{}`",
1400 /// Parse a possibly mutable type
1401 pub fn parse_mt(&mut self) -> MutTy {
1402 let mutbl = self.parse_mutability();
1403 let t = self.parse_ty();
1404 MutTy { ty: t, mutbl: mutbl }
1407 /// Parse [mut/const/imm] ID : TY
1408 /// now used only by obsolete record syntax parser...
1409 pub fn parse_ty_field(&mut self) -> TypeField {
1410 let lo = self.span.lo;
1411 let mutbl = self.parse_mutability();
1412 let id = self.parse_ident();
1413 self.expect(&token::Colon);
1414 let ty = self.parse_ty_sum();
1415 let hi = ty.span.hi;
1418 mt: MutTy { ty: ty, mutbl: mutbl },
1419 span: mk_sp(lo, hi),
1423 /// Parse optional return type [ -> TY ] in function decl
1424 pub fn parse_ret_ty(&mut self) -> FunctionRetTy {
1425 if self.eat(&token::RArrow) {
1426 if self.eat(&token::Not) {
1429 let t = self.parse_ty();
1431 // We used to allow `fn foo() -> &T + U`, but don't
1432 // anymore. If we see it, report a useful error. This
1433 // only makes sense because `parse_ret_ty` is only
1434 // used in fn *declarations*, not fn types or where
1435 // clauses (i.e., not when parsing something like
1436 // `FnMut() -> T + Send`, where the `+` is legal).
1437 if self.token == token::BinOp(token::Plus) {
1438 self.warn("deprecated syntax: `()` are required, see RFC 438 for details");
1444 let pos = self.span.lo;
1446 id: ast::DUMMY_NODE_ID,
1447 node: TyTup(vec![]),
1448 span: mk_sp(pos, pos),
1453 /// Parse a type in a context where `T1+T2` is allowed.
1454 pub fn parse_ty_sum(&mut self) -> P<Ty> {
1455 let lo = self.span.lo;
1456 let lhs = self.parse_ty();
1458 if !self.eat(&token::BinOp(token::Plus)) {
1462 let bounds = self.parse_ty_param_bounds(BoundParsingMode::Bare);
1464 // In type grammar, `+` is treated like a binary operator,
1465 // and hence both L and R side are required.
1466 if bounds.len() == 0 {
1467 let last_span = self.last_span;
1468 self.span_err(last_span,
1469 "at least one type parameter bound \
1470 must be specified");
1473 let sp = mk_sp(lo, self.last_span.hi);
1474 let sum = ast::TyObjectSum(lhs, bounds);
1475 P(Ty {id: ast::DUMMY_NODE_ID, node: sum, span: sp})
1479 pub fn parse_ty(&mut self) -> P<Ty> {
1480 maybe_whole!(no_clone self, NtTy);
1482 let lo = self.span.lo;
1484 let t = if self.check(&token::OpenDelim(token::Paren)) {
1487 // (t) is a parenthesized ty
1488 // (t,) is the type of a tuple with only one field,
1490 let mut ts = vec![];
1491 let mut last_comma = false;
1492 while self.token != token::CloseDelim(token::Paren) {
1493 ts.push(self.parse_ty_sum());
1494 if self.check(&token::Comma) {
1503 self.expect(&token::CloseDelim(token::Paren));
1504 if ts.len() == 1 && !last_comma {
1505 TyParen(ts.into_iter().nth(0).unwrap())
1509 } else if self.token == token::Tilde {
1512 let last_span = self.last_span;
1514 token::OpenDelim(token::Bracket) => {
1515 self.obsolete(last_span, ObsoleteSyntax::OwnedVector)
1517 _ => self.obsolete(last_span, ObsoleteSyntax::OwnedType)
1519 TyTup(vec![self.parse_ty()])
1520 } else if self.check(&token::BinOp(token::Star)) {
1521 // STAR POINTER (bare pointer?)
1523 TyPtr(self.parse_ptr())
1524 } else if self.check(&token::OpenDelim(token::Bracket)) {
1526 self.expect(&token::OpenDelim(token::Bracket));
1527 let t = self.parse_ty_sum();
1529 // Parse the `; e` in `[ int; e ]`
1530 // where `e` is a const expression
1531 let t = match self.maybe_parse_fixed_length_of_vec() {
1533 Some(suffix) => TyFixedLengthVec(t, suffix)
1535 self.expect(&token::CloseDelim(token::Bracket));
1537 } else if self.check(&token::BinOp(token::And)) ||
1538 self.token == token::AndAnd {
1541 self.parse_borrowed_pointee()
1542 } else if self.token.is_keyword(keywords::For) {
1543 self.parse_for_in_type()
1544 } else if self.token_is_bare_fn_keyword() ||
1545 self.token_is_closure_keyword() {
1546 // BARE FUNCTION OR CLOSURE
1547 self.parse_ty_bare_fn_or_ty_closure(Vec::new())
1548 } else if self.check(&token::BinOp(token::Or)) ||
1549 self.token == token::OrOr ||
1550 (self.token == token::Lt &&
1551 self.look_ahead(1, |t| {
1552 *t == token::Gt || t.is_lifetime()
1555 self.parse_ty_closure(Vec::new())
1556 } else if self.eat_keyword(keywords::Typeof) {
1558 // In order to not be ambiguous, the type must be surrounded by parens.
1559 self.expect(&token::OpenDelim(token::Paren));
1560 let e = self.parse_expr();
1561 self.expect(&token::CloseDelim(token::Paren));
1563 } else if self.eat_keyword(keywords::Proc) {
1564 self.parse_proc_type(Vec::new())
1565 } else if self.eat_lt() {
1566 // QUALIFIED PATH `<TYPE as TRAIT_REF>::item`
1567 let self_type = self.parse_ty_sum();
1568 self.expect_keyword(keywords::As);
1569 let trait_ref = self.parse_trait_ref();
1570 self.expect(&token::Gt);
1571 self.expect(&token::ModSep);
1572 let item_name = self.parse_ident();
1574 self_type: self_type,
1575 trait_ref: P(trait_ref),
1576 item_path: ast::PathSegment {
1577 identifier: item_name,
1578 parameters: ast::PathParameters::none()
1581 } else if self.check(&token::ModSep) ||
1582 self.token.is_ident() ||
1583 self.token.is_path() {
1585 self.parse_ty_path()
1586 } else if self.eat(&token::Underscore) {
1587 // TYPE TO BE INFERRED
1590 let this_token_str = self.this_token_to_string();
1591 let msg = format!("expected type, found `{}`", this_token_str);
1595 let sp = mk_sp(lo, self.last_span.hi);
1596 P(Ty {id: ast::DUMMY_NODE_ID, node: t, span: sp})
1599 pub fn parse_borrowed_pointee(&mut self) -> Ty_ {
1600 // look for `&'lt` or `&'foo ` and interpret `foo` as the region name:
1601 let opt_lifetime = self.parse_opt_lifetime();
1603 let mt = self.parse_mt();
1604 return TyRptr(opt_lifetime, mt);
1607 pub fn parse_ptr(&mut self) -> MutTy {
1608 let mutbl = if self.eat_keyword(keywords::Mut) {
1610 } else if self.eat_keyword(keywords::Const) {
1613 let span = self.last_span;
1615 "bare raw pointers are no longer allowed, you should \
1616 likely use `*mut T`, but otherwise `*T` is now \
1617 known as `*const T`");
1620 let t = self.parse_ty();
1621 MutTy { ty: t, mutbl: mutbl }
1624 pub fn is_named_argument(&mut self) -> bool {
1625 let offset = match self.token {
1626 token::BinOp(token::And) => 1,
1628 _ if self.token.is_keyword(keywords::Mut) => 1,
1632 debug!("parser is_named_argument offset:{}", offset);
1635 is_plain_ident_or_underscore(&self.token)
1636 && self.look_ahead(1, |t| *t == token::Colon)
1638 self.look_ahead(offset, |t| is_plain_ident_or_underscore(t))
1639 && self.look_ahead(offset + 1, |t| *t == token::Colon)
1643 /// This version of parse arg doesn't necessarily require
1644 /// identifier names.
1645 pub fn parse_arg_general(&mut self, require_name: bool) -> Arg {
1646 let pat = if require_name || self.is_named_argument() {
1647 debug!("parse_arg_general parse_pat (require_name:{})",
1649 let pat = self.parse_pat();
1651 self.expect(&token::Colon);
1654 debug!("parse_arg_general ident_to_pat");
1655 ast_util::ident_to_pat(ast::DUMMY_NODE_ID,
1657 special_idents::invalid)
1660 let t = self.parse_ty_sum();
1665 id: ast::DUMMY_NODE_ID,
1669 /// Parse a single function argument
1670 pub fn parse_arg(&mut self) -> Arg {
1671 self.parse_arg_general(true)
1674 /// Parse an argument in a lambda header e.g. |arg, arg|
1675 pub fn parse_fn_block_arg(&mut self) -> Arg {
1676 let pat = self.parse_pat();
1677 let t = if self.eat(&token::Colon) {
1681 id: ast::DUMMY_NODE_ID,
1683 span: mk_sp(self.span.lo, self.span.hi),
1689 id: ast::DUMMY_NODE_ID
1693 pub fn maybe_parse_fixed_length_of_vec(&mut self) -> Option<P<ast::Expr>> {
1694 if self.check(&token::Semi) {
1696 Some(self.parse_expr())
1702 /// Matches token_lit = LIT_INTEGER | ...
1703 pub fn lit_from_token(&mut self, tok: &token::Token) -> Lit_ {
1705 token::Interpolated(token::NtExpr(ref v)) => {
1707 ExprLit(ref lit) => { lit.node.clone() }
1708 _ => { self.unexpected_last(tok); }
1711 token::Literal(lit, suf) => {
1712 let (suffix_illegal, out) = match lit {
1713 token::Byte(i) => (true, LitByte(parse::byte_lit(i.as_str()).0)),
1714 token::Char(i) => (true, LitChar(parse::char_lit(i.as_str()).0)),
1716 // there are some valid suffixes for integer and
1717 // float literals, so all the handling is done
1719 token::Integer(s) => {
1720 (false, parse::integer_lit(s.as_str(),
1721 suf.as_ref().map(|s| s.as_str()),
1722 &self.sess.span_diagnostic,
1725 token::Float(s) => {
1726 (false, parse::float_lit(s.as_str(),
1727 suf.as_ref().map(|s| s.as_str()),
1728 &self.sess.span_diagnostic,
1734 LitStr(token::intern_and_get_ident(parse::str_lit(s.as_str()).as_slice()),
1737 token::StrRaw(s, n) => {
1740 token::intern_and_get_ident(&parse::raw_str_lit(s.as_str())[]),
1744 (true, LitBinary(parse::binary_lit(i.as_str()))),
1745 token::BinaryRaw(i, _) =>
1747 LitBinary(Rc::new(i.as_str().as_bytes().iter().map(|&x| x).collect()))),
1751 let sp = self.last_span;
1752 self.expect_no_suffix(sp, &*format!("{} literal", lit.short_name()), suf)
1757 _ => { self.unexpected_last(tok); }
1761 /// Matches lit = true | false | token_lit
1762 pub fn parse_lit(&mut self) -> Lit {
1763 let lo = self.span.lo;
1764 let lit = if self.eat_keyword(keywords::True) {
1766 } else if self.eat_keyword(keywords::False) {
1769 let token = self.bump_and_get();
1770 let lit = self.lit_from_token(&token);
1773 codemap::Spanned { node: lit, span: mk_sp(lo, self.last_span.hi) }
1776 /// matches '-' lit | lit
1777 pub fn parse_literal_maybe_minus(&mut self) -> P<Expr> {
1778 let minus_lo = self.span.lo;
1779 let minus_present = self.eat(&token::BinOp(token::Minus));
1781 let lo = self.span.lo;
1782 let literal = P(self.parse_lit());
1783 let hi = self.span.hi;
1784 let expr = self.mk_expr(lo, hi, ExprLit(literal));
1787 let minus_hi = self.span.hi;
1788 let unary = self.mk_unary(UnNeg, expr);
1789 self.mk_expr(minus_lo, minus_hi, unary)
1795 /// Parses a path and optional type parameter bounds, depending on the
1796 /// mode. The `mode` parameter determines whether lifetimes, types, and/or
1797 /// bounds are permitted and whether `::` must precede type parameter
1799 pub fn parse_path(&mut self, mode: PathParsingMode) -> ast::Path {
1800 // Check for a whole path...
1801 let found = match self.token {
1802 token::Interpolated(token::NtPath(_)) => Some(self.bump_and_get()),
1805 if let Some(token::Interpolated(token::NtPath(box path))) = found {
1809 let lo = self.span.lo;
1810 let is_global = self.eat(&token::ModSep);
1812 // Parse any number of segments and bound sets. A segment is an
1813 // identifier followed by an optional lifetime and a set of types.
1814 // A bound set is a set of type parameter bounds.
1815 let segments = match mode {
1816 LifetimeAndTypesWithoutColons => {
1817 self.parse_path_segments_without_colons()
1819 LifetimeAndTypesWithColons => {
1820 self.parse_path_segments_with_colons()
1823 self.parse_path_segments_without_types()
1827 // Assemble the span.
1828 let span = mk_sp(lo, self.last_span.hi);
1830 // Assemble the result.
1839 /// - `a::b<T,U>::c<V,W>`
1840 /// - `a::b<T,U>::c(V) -> W`
1841 /// - `a::b<T,U>::c(V)`
1842 pub fn parse_path_segments_without_colons(&mut self) -> Vec<ast::PathSegment> {
1843 let mut segments = Vec::new();
1845 // First, parse an identifier.
1846 let identifier = self.parse_ident();
1848 // Parse types, optionally.
1849 let parameters = if self.eat_lt() {
1850 let (lifetimes, types, bindings) = self.parse_generic_values_after_lt();
1852 ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
1853 lifetimes: lifetimes,
1854 types: OwnedSlice::from_vec(types),
1855 bindings: OwnedSlice::from_vec(bindings),
1857 } else if self.eat(&token::OpenDelim(token::Paren)) {
1858 let inputs = self.parse_seq_to_end(
1859 &token::CloseDelim(token::Paren),
1860 seq_sep_trailing_allowed(token::Comma),
1861 |p| p.parse_ty_sum());
1863 let output_ty = if self.eat(&token::RArrow) {
1864 Some(self.parse_ty())
1869 ast::ParenthesizedParameters(ast::ParenthesizedParameterData {
1874 ast::PathParameters::none()
1877 // Assemble and push the result.
1878 segments.push(ast::PathSegment { identifier: identifier,
1879 parameters: parameters });
1881 // Continue only if we see a `::`
1882 if !self.eat(&token::ModSep) {
1889 /// - `a::b::<T,U>::c`
1890 pub fn parse_path_segments_with_colons(&mut self) -> Vec<ast::PathSegment> {
1891 let mut segments = Vec::new();
1893 // First, parse an identifier.
1894 let identifier = self.parse_ident();
1896 // If we do not see a `::`, stop.
1897 if !self.eat(&token::ModSep) {
1898 segments.push(ast::PathSegment {
1899 identifier: identifier,
1900 parameters: ast::PathParameters::none()
1905 // Check for a type segment.
1907 // Consumed `a::b::<`, go look for types
1908 let (lifetimes, types, bindings) = self.parse_generic_values_after_lt();
1909 segments.push(ast::PathSegment {
1910 identifier: identifier,
1911 parameters: ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
1912 lifetimes: lifetimes,
1913 types: OwnedSlice::from_vec(types),
1914 bindings: OwnedSlice::from_vec(bindings),
1918 // Consumed `a::b::<T,U>`, check for `::` before proceeding
1919 if !self.eat(&token::ModSep) {
1923 // Consumed `a::`, go look for `b`
1924 segments.push(ast::PathSegment {
1925 identifier: identifier,
1926 parameters: ast::PathParameters::none(),
1935 pub fn parse_path_segments_without_types(&mut self) -> Vec<ast::PathSegment> {
1936 let mut segments = Vec::new();
1938 // First, parse an identifier.
1939 let identifier = self.parse_ident();
1941 // Assemble and push the result.
1942 segments.push(ast::PathSegment {
1943 identifier: identifier,
1944 parameters: ast::PathParameters::none()
1947 // If we do not see a `::`, stop.
1948 if !self.eat(&token::ModSep) {
1954 /// parses 0 or 1 lifetime
1955 pub fn parse_opt_lifetime(&mut self) -> Option<ast::Lifetime> {
1957 token::Lifetime(..) => {
1958 Some(self.parse_lifetime())
1966 /// Parses a single lifetime
1967 /// Matches lifetime = LIFETIME
1968 pub fn parse_lifetime(&mut self) -> ast::Lifetime {
1970 token::Lifetime(i) => {
1971 let span = self.span;
1973 return ast::Lifetime {
1974 id: ast::DUMMY_NODE_ID,
1980 self.fatal(&format!("expected a lifetime name")[]);
1985 /// Parses `lifetime_defs = [ lifetime_defs { ',' lifetime_defs } ]` where `lifetime_def =
1986 /// lifetime [':' lifetimes]`
1987 pub fn parse_lifetime_defs(&mut self) -> Vec<ast::LifetimeDef> {
1989 let mut res = Vec::new();
1992 token::Lifetime(_) => {
1993 let lifetime = self.parse_lifetime();
1995 if self.eat(&token::Colon) {
1996 self.parse_lifetimes(token::BinOp(token::Plus))
2000 res.push(ast::LifetimeDef { lifetime: lifetime,
2010 token::Comma => { self.bump(); }
2011 token::Gt => { return res; }
2012 token::BinOp(token::Shr) => { return res; }
2014 let this_token_str = self.this_token_to_string();
2015 let msg = format!("expected `,` or `>` after lifetime \
2024 /// matches lifetimes = ( lifetime ) | ( lifetime , lifetimes ) actually, it matches the empty
2025 /// one too, but putting that in there messes up the grammar....
2027 /// Parses zero or more comma separated lifetimes. Expects each lifetime to be followed by
2028 /// either a comma or `>`. Used when parsing type parameter lists, where we expect something
2029 /// like `<'a, 'b, T>`.
2030 pub fn parse_lifetimes(&mut self, sep: token::Token) -> Vec<ast::Lifetime> {
2032 let mut res = Vec::new();
2035 token::Lifetime(_) => {
2036 res.push(self.parse_lifetime());
2043 if self.token != sep {
2051 /// Parse mutability declaration (mut/const/imm)
2052 pub fn parse_mutability(&mut self) -> Mutability {
2053 if self.eat_keyword(keywords::Mut) {
2060 /// Parse ident COLON expr
2061 pub fn parse_field(&mut self) -> Field {
2062 let lo = self.span.lo;
2063 let i = self.parse_ident();
2064 let hi = self.last_span.hi;
2065 self.expect(&token::Colon);
2066 let e = self.parse_expr();
2068 ident: spanned(lo, hi, i),
2069 span: mk_sp(lo, e.span.hi),
2074 pub fn mk_expr(&mut self, lo: BytePos, hi: BytePos, node: Expr_) -> P<Expr> {
2076 id: ast::DUMMY_NODE_ID,
2078 span: mk_sp(lo, hi),
2082 pub fn mk_unary(&mut self, unop: ast::UnOp, expr: P<Expr>) -> ast::Expr_ {
2083 ExprUnary(unop, expr)
2086 pub fn mk_binary(&mut self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::Expr_ {
2087 ExprBinary(binop, lhs, rhs)
2090 pub fn mk_call(&mut self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::Expr_ {
2094 fn mk_method_call(&mut self,
2095 ident: ast::SpannedIdent,
2099 ExprMethodCall(ident, tps, args)
2102 pub fn mk_index(&mut self, expr: P<Expr>, idx: P<Expr>) -> ast::Expr_ {
2103 ExprIndex(expr, idx)
2106 pub fn mk_range(&mut self,
2107 start: Option<P<Expr>>,
2108 end: Option<P<Expr>>)
2110 ExprRange(start, end)
2113 pub fn mk_field(&mut self, expr: P<Expr>, ident: ast::SpannedIdent) -> ast::Expr_ {
2114 ExprField(expr, ident)
2117 pub fn mk_tup_field(&mut self, expr: P<Expr>, idx: codemap::Spanned<uint>) -> ast::Expr_ {
2118 ExprTupField(expr, idx)
2121 pub fn mk_assign_op(&mut self, binop: ast::BinOp,
2122 lhs: P<Expr>, rhs: P<Expr>) -> ast::Expr_ {
2123 ExprAssignOp(binop, lhs, rhs)
2126 pub fn mk_mac_expr(&mut self, lo: BytePos, hi: BytePos, m: Mac_) -> P<Expr> {
2128 id: ast::DUMMY_NODE_ID,
2129 node: ExprMac(codemap::Spanned {node: m, span: mk_sp(lo, hi)}),
2130 span: mk_sp(lo, hi),
2134 pub fn mk_lit_u32(&mut self, i: u32) -> P<Expr> {
2135 let span = &self.span;
2136 let lv_lit = P(codemap::Spanned {
2137 node: LitInt(i as u64, ast::UnsignedIntLit(TyU32)),
2142 id: ast::DUMMY_NODE_ID,
2143 node: ExprLit(lv_lit),
2148 fn expect_open_delim(&mut self) -> token::DelimToken {
2150 token::OpenDelim(delim) => {
2154 _ => self.fatal("expected open delimiter"),
2158 /// At the bottom (top?) of the precedence hierarchy,
2159 /// parse things like parenthesized exprs,
2160 /// macros, return, etc.
2161 pub fn parse_bottom_expr(&mut self) -> P<Expr> {
2162 maybe_whole_expr!(self);
2164 let lo = self.span.lo;
2165 let mut hi = self.span.hi;
2170 token::OpenDelim(token::Paren) => {
2173 // (e) is parenthesized e
2174 // (e,) is a tuple with only one field, e
2175 let mut es = vec![];
2176 let mut trailing_comma = false;
2177 while self.token != token::CloseDelim(token::Paren) {
2178 es.push(self.parse_expr());
2179 self.commit_expr(&**es.last().unwrap(), &[],
2180 &[token::Comma, token::CloseDelim(token::Paren)]);
2181 if self.check(&token::Comma) {
2182 trailing_comma = true;
2186 trailing_comma = false;
2193 return if es.len() == 1 && !trailing_comma {
2194 self.mk_expr(lo, hi, ExprParen(es.into_iter().nth(0).unwrap()))
2196 self.mk_expr(lo, hi, ExprTup(es))
2199 token::OpenDelim(token::Brace) => {
2201 let blk = self.parse_block_tail(lo, DefaultBlock);
2202 return self.mk_expr(blk.span.lo, blk.span.hi,
2205 token::BinOp(token::Or) | token::OrOr => {
2206 return self.parse_lambda_expr(CaptureByRef);
2208 // FIXME #13626: Should be able to stick in
2209 // token::SELF_KEYWORD_NAME
2210 token::Ident(id @ ast::Ident {
2211 name: ast::Name(token::SELF_KEYWORD_NAME_NUM),
2213 }, token::Plain) => {
2215 let path = ast_util::ident_to_path(mk_sp(lo, hi), id);
2216 ex = ExprPath(path);
2217 hi = self.last_span.hi;
2219 token::OpenDelim(token::Bracket) => {
2222 if self.check(&token::CloseDelim(token::Bracket)) {
2225 ex = ExprVec(Vec::new());
2228 let first_expr = self.parse_expr();
2229 if self.check(&token::Semi) {
2230 // Repeating vector syntax: [ 0; 512 ]
2232 let count = self.parse_expr();
2233 self.expect(&token::CloseDelim(token::Bracket));
2234 ex = ExprRepeat(first_expr, count);
2235 } else if self.check(&token::Comma) {
2236 // Vector with two or more elements.
2238 let remaining_exprs = self.parse_seq_to_end(
2239 &token::CloseDelim(token::Bracket),
2240 seq_sep_trailing_allowed(token::Comma),
2243 let mut exprs = vec!(first_expr);
2244 exprs.extend(remaining_exprs.into_iter());
2245 ex = ExprVec(exprs);
2247 // Vector with one element.
2248 self.expect(&token::CloseDelim(token::Bracket));
2249 ex = ExprVec(vec!(first_expr));
2252 hi = self.last_span.hi;
2256 // QUALIFIED PATH `<TYPE as TRAIT_REF>::item::<'a, T>`
2257 let self_type = self.parse_ty_sum();
2258 self.expect_keyword(keywords::As);
2259 let trait_ref = self.parse_trait_ref();
2260 self.expect(&token::Gt);
2261 self.expect(&token::ModSep);
2262 let item_name = self.parse_ident();
2263 let parameters = if self.eat(&token::ModSep) {
2265 // Consumed `item::<`, go look for types
2266 let (lifetimes, types, bindings) =
2267 self.parse_generic_values_after_lt();
2268 ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
2269 lifetimes: lifetimes,
2270 types: OwnedSlice::from_vec(types),
2271 bindings: OwnedSlice::from_vec(bindings),
2274 ast::PathParameters::none()
2276 let hi = self.span.hi;
2277 return self.mk_expr(lo, hi, ExprQPath(P(QPath {
2278 self_type: self_type,
2279 trait_ref: P(trait_ref),
2280 item_path: ast::PathSegment {
2281 identifier: item_name,
2282 parameters: parameters
2286 if self.eat_keyword(keywords::Move) {
2287 return self.parse_lambda_expr(CaptureByValue);
2289 if self.eat_keyword(keywords::Proc) {
2290 let span = self.last_span;
2291 let _ = self.parse_proc_decl();
2292 let _ = self.parse_expr();
2293 return self.obsolete_expr(span, ObsoleteSyntax::ProcExpr);
2295 if self.eat_keyword(keywords::If) {
2296 return self.parse_if_expr();
2298 if self.eat_keyword(keywords::For) {
2299 return self.parse_for_expr(None);
2301 if self.eat_keyword(keywords::While) {
2302 return self.parse_while_expr(None);
2304 if self.token.is_lifetime() {
2305 let lifetime = self.get_lifetime();
2307 self.expect(&token::Colon);
2308 if self.eat_keyword(keywords::While) {
2309 return self.parse_while_expr(Some(lifetime))
2311 if self.eat_keyword(keywords::For) {
2312 return self.parse_for_expr(Some(lifetime))
2314 if self.eat_keyword(keywords::Loop) {
2315 return self.parse_loop_expr(Some(lifetime))
2317 self.fatal("expected `while`, `for`, or `loop` after a label")
2319 if self.eat_keyword(keywords::Loop) {
2320 return self.parse_loop_expr(None);
2322 if self.eat_keyword(keywords::Continue) {
2323 let lo = self.span.lo;
2324 let ex = if self.token.is_lifetime() {
2325 let lifetime = self.get_lifetime();
2327 ExprAgain(Some(lifetime))
2331 let hi = self.span.hi;
2332 return self.mk_expr(lo, hi, ex);
2334 if self.eat_keyword(keywords::Match) {
2335 return self.parse_match_expr();
2337 if self.eat_keyword(keywords::Unsafe) {
2338 return self.parse_block_expr(
2340 UnsafeBlock(ast::UserProvided));
2342 if self.eat_keyword(keywords::Return) {
2343 // RETURN expression
2344 if self.token.can_begin_expr() {
2345 let e = self.parse_expr();
2347 ex = ExprRet(Some(e));
2351 } else if self.eat_keyword(keywords::Break) {
2353 if self.token.is_lifetime() {
2354 let lifetime = self.get_lifetime();
2356 ex = ExprBreak(Some(lifetime));
2358 ex = ExprBreak(None);
2361 } else if self.check(&token::ModSep) ||
2362 self.token.is_ident() &&
2363 !self.token.is_keyword(keywords::True) &&
2364 !self.token.is_keyword(keywords::False) {
2366 self.parse_path(LifetimeAndTypesWithColons);
2368 // `!`, as an operator, is prefix, so we know this isn't that
2369 if self.check(&token::Not) {
2370 // MACRO INVOCATION expression
2373 let delim = self.expect_open_delim();
2374 let tts = self.parse_seq_to_end(
2375 &token::CloseDelim(delim),
2377 |p| p.parse_token_tree());
2378 let hi = self.span.hi;
2380 return self.mk_mac_expr(lo,
2386 if self.check(&token::OpenDelim(token::Brace)) {
2387 // This is a struct literal, unless we're prohibited
2388 // from parsing struct literals here.
2389 if !self.restrictions.contains(RESTRICTION_NO_STRUCT_LITERAL) {
2390 // It's a struct literal.
2392 let mut fields = Vec::new();
2393 let mut base = None;
2395 while self.token != token::CloseDelim(token::Brace) {
2396 if self.eat(&token::DotDot) {
2397 base = Some(self.parse_expr());
2401 fields.push(self.parse_field());
2402 self.commit_expr(&*fields.last().unwrap().expr,
2404 &[token::CloseDelim(token::Brace)]);
2407 if fields.len() == 0 && base.is_none() {
2408 let last_span = self.last_span;
2409 self.span_err(last_span,
2410 "structure literal must either \
2411 have at least one field or use \
2412 functional structure update \
2417 self.expect(&token::CloseDelim(token::Brace));
2418 ex = ExprStruct(pth, fields, base);
2419 return self.mk_expr(lo, hi, ex);
2426 // other literal expression
2427 let lit = self.parse_lit();
2429 ex = ExprLit(P(lit));
2434 return self.mk_expr(lo, hi, ex);
2437 /// Parse a block or unsafe block
2438 pub fn parse_block_expr(&mut self, lo: BytePos, blk_mode: BlockCheckMode)
2440 self.expect(&token::OpenDelim(token::Brace));
2441 let blk = self.parse_block_tail(lo, blk_mode);
2442 return self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk));
2445 /// parse a.b or a(13) or a[4] or just a
2446 pub fn parse_dot_or_call_expr(&mut self) -> P<Expr> {
2447 let b = self.parse_bottom_expr();
2448 self.parse_dot_or_call_expr_with(b)
2451 pub fn parse_dot_or_call_expr_with(&mut self, e0: P<Expr>) -> P<Expr> {
2457 if self.eat(&token::Dot) {
2459 token::Ident(i, _) => {
2460 let dot = self.last_span.hi;
2463 let (_, tys, bindings) = if self.eat(&token::ModSep) {
2465 self.parse_generic_values_after_lt()
2467 (Vec::new(), Vec::new(), Vec::new())
2470 if bindings.len() > 0 {
2471 let last_span = self.last_span;
2472 self.span_err(last_span, "type bindings are only permitted on trait paths");
2475 // expr.f() method call
2477 token::OpenDelim(token::Paren) => {
2478 let mut es = self.parse_unspanned_seq(
2479 &token::OpenDelim(token::Paren),
2480 &token::CloseDelim(token::Paren),
2481 seq_sep_trailing_allowed(token::Comma),
2484 hi = self.last_span.hi;
2487 let id = spanned(dot, hi, i);
2488 let nd = self.mk_method_call(id, tys, es);
2489 e = self.mk_expr(lo, hi, nd);
2492 if !tys.is_empty() {
2493 let last_span = self.last_span;
2494 self.span_err(last_span,
2495 "field expressions may not \
2496 have type parameters");
2499 let id = spanned(dot, hi, i);
2500 let field = self.mk_field(e, id);
2501 e = self.mk_expr(lo, hi, field);
2505 token::Literal(token::Integer(n), suf) => {
2508 // A tuple index may not have a suffix
2509 self.expect_no_suffix(sp, "tuple index", suf);
2511 let dot = self.last_span.hi;
2515 let index = n.as_str().parse::<uint>();
2518 let id = spanned(dot, hi, n);
2519 let field = self.mk_tup_field(e, id);
2520 e = self.mk_expr(lo, hi, field);
2523 let last_span = self.last_span;
2524 self.span_err(last_span, "invalid tuple or tuple struct index");
2528 token::Literal(token::Float(n), _suf) => {
2530 let last_span = self.last_span;
2531 let fstr = n.as_str();
2532 self.span_err(last_span,
2533 &format!("unexpected token: `{}`", n.as_str())[]);
2534 if fstr.chars().all(|x| "0123456789.".contains_char(x)) {
2535 let float = match fstr.parse::<f64>() {
2539 self.span_help(last_span,
2540 &format!("try parenthesizing the first index; e.g., `(foo.{}){}`",
2541 float.trunc() as uint,
2542 &float.fract().to_string()[1..])[]);
2544 self.abort_if_errors();
2547 _ => self.unexpected()
2551 if self.expr_is_complete(&*e) { break; }
2554 token::OpenDelim(token::Paren) => {
2555 let es = self.parse_unspanned_seq(
2556 &token::OpenDelim(token::Paren),
2557 &token::CloseDelim(token::Paren),
2558 seq_sep_trailing_allowed(token::Comma),
2561 hi = self.last_span.hi;
2563 let nd = self.mk_call(e, es);
2564 e = self.mk_expr(lo, hi, nd);
2568 // Could be either an index expression or a slicing expression.
2569 token::OpenDelim(token::Bracket) => {
2570 let bracket_pos = self.span.lo;
2573 let mut found_dotdot = false;
2574 if self.token == token::DotDot &&
2575 self.look_ahead(1, |t| t == &token::CloseDelim(token::Bracket)) {
2576 // Using expr[..], which is a mistake, should be expr[]
2579 found_dotdot = true;
2582 if found_dotdot || self.eat(&token::CloseDelim(token::Bracket)) {
2583 // No expression, expand to a FullRange
2584 // FIXME(#20516) It would be better to use a lang item or
2585 // something for FullRange.
2586 hi = self.last_span.hi;
2587 let range = ExprStruct(ident_to_path(mk_sp(lo, hi),
2588 token::special_idents::FullRange),
2591 let ix = self.mk_expr(bracket_pos, hi, range);
2592 let index = self.mk_index(e, ix);
2593 e = self.mk_expr(lo, hi, index)
2595 let ix = self.parse_expr();
2597 self.commit_expr_expecting(&*ix, token::CloseDelim(token::Bracket));
2598 let index = self.mk_index(e, ix);
2599 e = self.mk_expr(lo, hi, index)
2603 self.span_err(e.span, "incorrect slicing expression: `[..]`");
2604 self.span_note(e.span,
2605 "use `&expr[]` to construct a slice of the whole of expr");
2614 // Parse unquoted tokens after a `$` in a token tree
2615 fn parse_unquoted(&mut self) -> TokenTree {
2616 let mut sp = self.span;
2617 let (name, namep) = match self.token {
2621 if self.token == token::OpenDelim(token::Paren) {
2622 let Spanned { node: seq, span: seq_span } = self.parse_seq(
2623 &token::OpenDelim(token::Paren),
2624 &token::CloseDelim(token::Paren),
2626 |p| p.parse_token_tree()
2628 let (sep, repeat) = self.parse_sep_and_kleene_op();
2629 let name_num = macro_parser::count_names(seq.as_slice());
2630 return TtSequence(mk_sp(sp.lo, seq_span.hi),
2631 Rc::new(SequenceRepetition {
2635 num_captures: name_num
2637 } else if self.token.is_keyword_allow_following_colon(keywords::Crate) {
2639 return TtToken(sp, SpecialVarNt(SpecialMacroVar::CrateMacroVar));
2641 sp = mk_sp(sp.lo, self.span.hi);
2642 let namep = match self.token { token::Ident(_, p) => p, _ => token::Plain };
2643 let name = self.parse_ident();
2647 token::SubstNt(name, namep) => {
2653 // continue by trying to parse the `:ident` after `$name`
2654 if self.token == token::Colon && self.look_ahead(1, |t| t.is_ident() &&
2655 !t.is_strict_keyword() &&
2656 !t.is_reserved_keyword()) {
2658 sp = mk_sp(sp.lo, self.span.hi);
2659 let kindp = match self.token { token::Ident(_, p) => p, _ => token::Plain };
2660 let nt_kind = self.parse_ident();
2661 TtToken(sp, MatchNt(name, nt_kind, namep, kindp))
2663 TtToken(sp, SubstNt(name, namep))
2667 pub fn check_unknown_macro_variable(&mut self) {
2668 if self.quote_depth == 0u {
2670 token::SubstNt(name, _) =>
2671 self.fatal(&format!("unknown macro variable `{}`",
2672 token::get_ident(name))[]),
2678 /// Parse an optional separator followed by a Kleene-style
2679 /// repetition token (+ or *).
2680 pub fn parse_sep_and_kleene_op(&mut self) -> (Option<token::Token>, ast::KleeneOp) {
2681 fn parse_kleene_op(parser: &mut Parser) -> Option<ast::KleeneOp> {
2682 match parser.token {
2683 token::BinOp(token::Star) => {
2685 Some(ast::ZeroOrMore)
2687 token::BinOp(token::Plus) => {
2689 Some(ast::OneOrMore)
2695 match parse_kleene_op(self) {
2696 Some(kleene_op) => return (None, kleene_op),
2700 let separator = self.bump_and_get();
2701 match parse_kleene_op(self) {
2702 Some(zerok) => (Some(separator), zerok),
2703 None => self.fatal("expected `*` or `+`")
2707 /// parse a single token tree from the input.
2708 pub fn parse_token_tree(&mut self) -> TokenTree {
2709 // FIXME #6994: currently, this is too eager. It
2710 // parses token trees but also identifies TtSequence's
2711 // and token::SubstNt's; it's too early to know yet
2712 // whether something will be a nonterminal or a seq
2714 maybe_whole!(deref self, NtTT);
2716 // this is the fall-through for the 'match' below.
2717 // invariants: the current token is not a left-delimiter,
2718 // not an EOF, and not the desired right-delimiter (if
2719 // it were, parse_seq_to_before_end would have prevented
2720 // reaching this point.
2721 fn parse_non_delim_tt_tok(p: &mut Parser) -> TokenTree {
2722 maybe_whole!(deref p, NtTT);
2724 token::CloseDelim(_) => {
2725 // This is a conservative error: only report the last unclosed delimiter. The
2726 // previous unclosed delimiters could actually be closed! The parser just hasn't
2727 // gotten to them yet.
2728 match p.open_braces.last() {
2730 Some(&sp) => p.span_note(sp, "unclosed delimiter"),
2732 let token_str = p.this_token_to_string();
2733 p.fatal(&format!("incorrect close delimiter: `{}`",
2736 /* we ought to allow different depths of unquotation */
2737 token::Dollar | token::SubstNt(..) if p.quote_depth > 0u => {
2741 TtToken(p.span, p.bump_and_get())
2748 let open_braces = self.open_braces.clone();
2749 for sp in open_braces.iter() {
2750 self.span_help(*sp, "did you mean to close this delimiter?");
2752 // There shouldn't really be a span, but it's easier for the test runner
2753 // if we give it one
2754 self.fatal("this file contains an un-closed delimiter ");
2756 token::OpenDelim(delim) => {
2757 // The span for beginning of the delimited section
2758 let pre_span = self.span;
2760 // Parse the open delimiter.
2761 self.open_braces.push(self.span);
2762 let open_span = self.span;
2765 // Parse the token trees within the delimiters
2766 let tts = self.parse_seq_to_before_end(
2767 &token::CloseDelim(delim),
2769 |p| p.parse_token_tree()
2772 // Parse the close delimiter.
2773 let close_span = self.span;
2775 self.open_braces.pop().unwrap();
2777 // Expand to cover the entire delimited token tree
2778 let span = Span { hi: self.span.hi, ..pre_span };
2780 TtDelimited(span, Rc::new(Delimited {
2782 open_span: open_span,
2784 close_span: close_span,
2787 _ => parse_non_delim_tt_tok(self),
2791 // parse a stream of tokens into a list of TokenTree's,
2793 pub fn parse_all_token_trees(&mut self) -> Vec<TokenTree> {
2794 let mut tts = Vec::new();
2795 while self.token != token::Eof {
2796 tts.push(self.parse_token_tree());
2801 /// Parse a prefix-operator expr
2802 pub fn parse_prefix_expr(&mut self) -> P<Expr> {
2803 let lo = self.span.lo;
2810 let e = self.parse_prefix_expr();
2812 ex = self.mk_unary(UnNot, e);
2814 token::BinOp(token::Minus) => {
2816 let e = self.parse_prefix_expr();
2818 ex = self.mk_unary(UnNeg, e);
2820 token::BinOp(token::Star) => {
2822 let e = self.parse_prefix_expr();
2824 ex = self.mk_unary(UnDeref, e);
2826 token::BinOp(token::And) | token::AndAnd => {
2828 let m = self.parse_mutability();
2829 let e = self.parse_prefix_expr();
2831 ex = ExprAddrOf(m, e);
2835 let last_span = self.last_span;
2837 token::OpenDelim(token::Bracket) => {
2838 self.obsolete(last_span, ObsoleteSyntax::OwnedVector)
2840 _ => self.obsolete(last_span, ObsoleteSyntax::OwnedExpr)
2843 let e = self.parse_prefix_expr();
2845 ex = self.mk_unary(UnUniq, e);
2847 token::DotDot if !self.restrictions.contains(RESTRICTION_NO_DOTS) => {
2848 // A range, closed above: `..expr`.
2850 let e = self.parse_expr();
2852 ex = self.mk_range(None, Some(e));
2854 token::Ident(_, _) => {
2855 if !self.token.is_keyword(keywords::Box) {
2856 return self.parse_dot_or_call_expr();
2859 let lo = self.span.lo;
2863 // Check for a place: `box(PLACE) EXPR`.
2864 if self.eat(&token::OpenDelim(token::Paren)) {
2865 // Support `box() EXPR` as the default.
2866 if !self.eat(&token::CloseDelim(token::Paren)) {
2867 let place = self.parse_expr();
2868 self.expect(&token::CloseDelim(token::Paren));
2869 // Give a suggestion to use `box()` when a parenthesised expression is used
2870 if !self.token.can_begin_expr() {
2871 let span = self.span;
2872 let this_token_to_string = self.this_token_to_string();
2874 &format!("expected expression, found `{}`",
2875 this_token_to_string)[]);
2876 let box_span = mk_sp(lo, self.last_span.hi);
2877 self.span_help(box_span,
2878 "perhaps you meant `box() (foo)` instead?");
2879 self.abort_if_errors();
2881 let subexpression = self.parse_prefix_expr();
2882 hi = subexpression.span.hi;
2883 ex = ExprBox(Some(place), subexpression);
2884 return self.mk_expr(lo, hi, ex);
2888 // Otherwise, we use the unique pointer default.
2889 let subexpression = self.parse_prefix_expr();
2890 hi = subexpression.span.hi;
2891 // FIXME (pnkfelix): After working out kinks with box
2892 // desugaring, should be `ExprBox(None, subexpression)`
2894 ex = self.mk_unary(UnUniq, subexpression);
2896 _ => return self.parse_dot_or_call_expr()
2898 return self.mk_expr(lo, hi, ex);
2901 /// Parse an expression of binops
2902 pub fn parse_binops(&mut self) -> P<Expr> {
2903 let prefix_expr = self.parse_prefix_expr();
2904 self.parse_more_binops(prefix_expr, 0)
2907 /// Parse an expression of binops of at least min_prec precedence
2908 pub fn parse_more_binops(&mut self, lhs: P<Expr>, min_prec: uint) -> P<Expr> {
2909 if self.expr_is_complete(&*lhs) { return lhs; }
2911 // Prevent dynamic borrow errors later on by limiting the
2912 // scope of the borrows.
2913 if self.token == token::BinOp(token::Or) &&
2914 self.restrictions.contains(RESTRICTION_NO_BAR_OP) {
2918 self.expected_tokens.push(TokenType::Operator);
2920 let cur_opt = self.token.to_binop();
2923 if ast_util::is_comparison_binop(cur_op) {
2924 self.check_no_chained_comparison(&*lhs, cur_op)
2926 let cur_prec = operator_prec(cur_op);
2927 if cur_prec > min_prec {
2929 let expr = self.parse_prefix_expr();
2930 let rhs = self.parse_more_binops(expr, cur_prec);
2931 let lhs_span = lhs.span;
2932 let rhs_span = rhs.span;
2933 let binary = self.mk_binary(cur_op, lhs, rhs);
2934 let bin = self.mk_expr(lhs_span.lo, rhs_span.hi, binary);
2935 self.parse_more_binops(bin, min_prec)
2941 if as_prec > min_prec && self.eat_keyword(keywords::As) {
2942 let rhs = self.parse_ty();
2943 let _as = self.mk_expr(lhs.span.lo,
2945 ExprCast(lhs, rhs));
2946 self.parse_more_binops(_as, min_prec)
2954 /// Produce an error if comparison operators are chained (RFC #558).
2955 /// We only need to check lhs, not rhs, because all comparison ops
2956 /// have same precedence and are left-associative
2957 fn check_no_chained_comparison(&mut self, lhs: &Expr, outer_op: ast::BinOp) {
2958 debug_assert!(ast_util::is_comparison_binop(outer_op));
2960 ExprBinary(op, _, _) if ast_util::is_comparison_binop(op) => {
2961 let op_span = self.span;
2962 self.span_err(op_span,
2963 "Chained comparison operators require parentheses");
2964 if op == BiLt && outer_op == BiGt {
2965 self.span_help(op_span,
2966 "Use ::< instead of < if you meant to specify type arguments.");
2973 /// Parse an assignment expression....
2974 /// actually, this seems to be the main entry point for
2975 /// parsing an arbitrary expression.
2976 pub fn parse_assign_expr(&mut self) -> P<Expr> {
2977 let lhs = self.parse_binops();
2978 self.parse_assign_expr_with(lhs)
2981 pub fn parse_assign_expr_with(&mut self, lhs: P<Expr>) -> P<Expr> {
2982 let restrictions = self.restrictions & RESTRICTION_NO_STRUCT_LITERAL;
2986 let rhs = self.parse_expr_res(restrictions);
2987 self.mk_expr(lhs.span.lo, rhs.span.hi, ExprAssign(lhs, rhs))
2989 token::BinOpEq(op) => {
2991 let rhs = self.parse_expr_res(restrictions);
2992 let aop = match op {
2993 token::Plus => BiAdd,
2994 token::Minus => BiSub,
2995 token::Star => BiMul,
2996 token::Slash => BiDiv,
2997 token::Percent => BiRem,
2998 token::Caret => BiBitXor,
2999 token::And => BiBitAnd,
3000 token::Or => BiBitOr,
3001 token::Shl => BiShl,
3004 let rhs_span = rhs.span;
3005 let span = lhs.span;
3006 let assign_op = self.mk_assign_op(aop, lhs, rhs);
3007 self.mk_expr(span.lo, rhs_span.hi, assign_op)
3009 // A range expression, either `expr..expr` or `expr..`.
3010 token::DotDot if !self.restrictions.contains(RESTRICTION_NO_DOTS) => {
3013 let opt_end = if self.token.can_begin_expr() {
3014 let end = self.parse_expr_res(RESTRICTION_NO_DOTS);
3020 let lo = lhs.span.lo;
3021 let hi = self.span.hi;
3022 let range = self.mk_range(Some(lhs), opt_end);
3023 return self.mk_expr(lo, hi, range);
3032 /// Parse an 'if' or 'if let' expression ('if' token already eaten)
3033 pub fn parse_if_expr(&mut self) -> P<Expr> {
3034 if self.token.is_keyword(keywords::Let) {
3035 return self.parse_if_let_expr();
3037 let lo = self.last_span.lo;
3038 let cond = self.parse_expr_res(RESTRICTION_NO_STRUCT_LITERAL);
3039 let thn = self.parse_block();
3040 let mut els: Option<P<Expr>> = None;
3041 let mut hi = thn.span.hi;
3042 if self.eat_keyword(keywords::Else) {
3043 let elexpr = self.parse_else_expr();
3044 hi = elexpr.span.hi;
3047 self.mk_expr(lo, hi, ExprIf(cond, thn, els))
3050 /// Parse an 'if let' expression ('if' token already eaten)
3051 pub fn parse_if_let_expr(&mut self) -> P<Expr> {
3052 let lo = self.last_span.lo;
3053 self.expect_keyword(keywords::Let);
3054 let pat = self.parse_pat();
3055 self.expect(&token::Eq);
3056 let expr = self.parse_expr_res(RESTRICTION_NO_STRUCT_LITERAL);
3057 let thn = self.parse_block();
3058 let (hi, els) = if self.eat_keyword(keywords::Else) {
3059 let expr = self.parse_else_expr();
3060 (expr.span.hi, Some(expr))
3064 self.mk_expr(lo, hi, ExprIfLet(pat, expr, thn, els))
3068 pub fn parse_lambda_expr(&mut self, capture_clause: CaptureClause)
3071 let lo = self.span.lo;
3072 let (decl, optional_unboxed_closure_kind) =
3073 self.parse_fn_block_decl();
3074 let body = self.parse_expr();
3075 let fakeblock = P(ast::Block {
3076 id: ast::DUMMY_NODE_ID,
3077 view_items: Vec::new(),
3081 rules: DefaultBlock,
3087 ExprClosure(capture_clause, optional_unboxed_closure_kind, decl, fakeblock))
3090 pub fn parse_else_expr(&mut self) -> P<Expr> {
3091 if self.eat_keyword(keywords::If) {
3092 return self.parse_if_expr();
3094 let blk = self.parse_block();
3095 return self.mk_expr(blk.span.lo, blk.span.hi, ExprBlock(blk));
3099 /// Parse a 'for' .. 'in' expression ('for' token already eaten)
3100 pub fn parse_for_expr(&mut self, opt_ident: Option<ast::Ident>) -> P<Expr> {
3101 // Parse: `for <src_pat> in <src_expr> <src_loop_block>`
3103 let lo = self.last_span.lo;
3104 let pat = self.parse_pat();
3105 self.expect_keyword(keywords::In);
3106 let expr = self.parse_expr_res(RESTRICTION_NO_STRUCT_LITERAL);
3107 let loop_block = self.parse_block();
3108 let hi = self.span.hi;
3110 self.mk_expr(lo, hi, ExprForLoop(pat, expr, loop_block, opt_ident))
3113 /// Parse a 'while' or 'while let' expression ('while' token already eaten)
3114 pub fn parse_while_expr(&mut self, opt_ident: Option<ast::Ident>) -> P<Expr> {
3115 if self.token.is_keyword(keywords::Let) {
3116 return self.parse_while_let_expr(opt_ident);
3118 let lo = self.last_span.lo;
3119 let cond = self.parse_expr_res(RESTRICTION_NO_STRUCT_LITERAL);
3120 let body = self.parse_block();
3121 let hi = body.span.hi;
3122 return self.mk_expr(lo, hi, ExprWhile(cond, body, opt_ident));
3125 /// Parse a 'while let' expression ('while' token already eaten)
3126 pub fn parse_while_let_expr(&mut self, opt_ident: Option<ast::Ident>) -> P<Expr> {
3127 let lo = self.last_span.lo;
3128 self.expect_keyword(keywords::Let);
3129 let pat = self.parse_pat();
3130 self.expect(&token::Eq);
3131 let expr = self.parse_expr_res(RESTRICTION_NO_STRUCT_LITERAL);
3132 let body = self.parse_block();
3133 let hi = body.span.hi;
3134 return self.mk_expr(lo, hi, ExprWhileLet(pat, expr, body, opt_ident));
3137 pub fn parse_loop_expr(&mut self, opt_ident: Option<ast::Ident>) -> P<Expr> {
3138 let lo = self.last_span.lo;
3139 let body = self.parse_block();
3140 let hi = body.span.hi;
3141 self.mk_expr(lo, hi, ExprLoop(body, opt_ident))
3144 fn parse_match_expr(&mut self) -> P<Expr> {
3145 let lo = self.last_span.lo;
3146 let discriminant = self.parse_expr_res(RESTRICTION_NO_STRUCT_LITERAL);
3147 self.commit_expr_expecting(&*discriminant, token::OpenDelim(token::Brace));
3148 let mut arms: Vec<Arm> = Vec::new();
3149 while self.token != token::CloseDelim(token::Brace) {
3150 arms.push(self.parse_arm());
3152 let hi = self.span.hi;
3154 return self.mk_expr(lo, hi, ExprMatch(discriminant, arms, MatchSource::Normal));
3157 pub fn parse_arm(&mut self) -> Arm {
3158 let attrs = self.parse_outer_attributes();
3159 let pats = self.parse_pats();
3160 let mut guard = None;
3161 if self.eat_keyword(keywords::If) {
3162 guard = Some(self.parse_expr());
3164 self.expect(&token::FatArrow);
3165 let expr = self.parse_expr_res(RESTRICTION_STMT_EXPR);
3168 !classify::expr_is_simple_block(&*expr)
3169 && self.token != token::CloseDelim(token::Brace);
3172 self.commit_expr(&*expr, &[token::Comma], &[token::CloseDelim(token::Brace)]);
3174 self.eat(&token::Comma);
3185 /// Parse an expression
3186 pub fn parse_expr(&mut self) -> P<Expr> {
3187 return self.parse_expr_res(UNRESTRICTED);
3190 /// Parse an expression, subject to the given restrictions
3191 pub fn parse_expr_res(&mut self, r: Restrictions) -> P<Expr> {
3192 let old = self.restrictions;
3193 self.restrictions = r;
3194 let e = self.parse_assign_expr();
3195 self.restrictions = old;
3199 /// Parse the RHS of a local variable declaration (e.g. '= 14;')
3200 fn parse_initializer(&mut self) -> Option<P<Expr>> {
3201 if self.check(&token::Eq) {
3203 Some(self.parse_expr())
3209 /// Parse patterns, separated by '|' s
3210 fn parse_pats(&mut self) -> Vec<P<Pat>> {
3211 let mut pats = Vec::new();
3213 pats.push(self.parse_pat());
3214 if self.check(&token::BinOp(token::Or)) { self.bump(); }
3215 else { return pats; }
3219 fn parse_pat_vec_elements(
3221 ) -> (Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>) {
3222 let mut before = Vec::new();
3223 let mut slice = None;
3224 let mut after = Vec::new();
3225 let mut first = true;
3226 let mut before_slice = true;
3228 while self.token != token::CloseDelim(token::Bracket) {
3232 self.expect(&token::Comma);
3234 if self.token == token::CloseDelim(token::Bracket)
3235 && (before_slice || after.len() != 0) {
3241 if self.check(&token::DotDot) {
3244 if self.check(&token::Comma) ||
3245 self.check(&token::CloseDelim(token::Bracket)) {
3246 slice = Some(P(ast::Pat {
3247 id: ast::DUMMY_NODE_ID,
3248 node: PatWild(PatWildMulti),
3251 before_slice = false;
3253 let _ = self.parse_pat();
3254 let span = self.span;
3255 self.obsolete(span, ObsoleteSyntax::SubsliceMatch);
3261 let subpat = self.parse_pat();
3262 if before_slice && self.check(&token::DotDot) {
3264 slice = Some(subpat);
3265 before_slice = false;
3266 } else if before_slice {
3267 before.push(subpat);
3273 (before, slice, after)
3276 /// Parse the fields of a struct-like pattern
3277 fn parse_pat_fields(&mut self) -> (Vec<codemap::Spanned<ast::FieldPat>> , bool) {
3278 let mut fields = Vec::new();
3279 let mut etc = false;
3280 let mut first = true;
3281 while self.token != token::CloseDelim(token::Brace) {
3285 self.expect(&token::Comma);
3286 // accept trailing commas
3287 if self.check(&token::CloseDelim(token::Brace)) { break }
3290 let lo = self.span.lo;
3293 if self.check(&token::DotDot) {
3295 if self.token != token::CloseDelim(token::Brace) {
3296 let token_str = self.this_token_to_string();
3297 self.fatal(&format!("expected `{}`, found `{}`", "}",
3304 let bind_type = if self.eat_keyword(keywords::Mut) {
3305 BindByValue(MutMutable)
3306 } else if self.eat_keyword(keywords::Ref) {
3307 BindByRef(self.parse_mutability())
3309 BindByValue(MutImmutable)
3312 let fieldname = self.parse_ident();
3314 let (subpat, is_shorthand) = if self.check(&token::Colon) {
3316 BindByRef(..) | BindByValue(MutMutable) => {
3317 let token_str = self.this_token_to_string();
3318 self.fatal(&format!("unexpected `{}`",
3325 let pat = self.parse_pat();
3329 hi = self.last_span.hi;
3330 let fieldpath = codemap::Spanned{span:self.last_span, node: fieldname};
3332 id: ast::DUMMY_NODE_ID,
3333 node: PatIdent(bind_type, fieldpath, None),
3334 span: self.last_span
3337 fields.push(codemap::Spanned { span: mk_sp(lo, hi),
3338 node: ast::FieldPat { ident: fieldname,
3340 is_shorthand: is_shorthand }});
3342 return (fields, etc);
3345 /// Parse a pattern.
3346 pub fn parse_pat(&mut self) -> P<Pat> {
3347 maybe_whole!(self, NtPat);
3349 let lo = self.span.lo;
3354 token::Underscore => {
3356 pat = PatWild(PatWildSingle);
3357 hi = self.last_span.hi;
3359 id: ast::DUMMY_NODE_ID,
3367 let sub = self.parse_pat();
3369 let last_span = self.last_span;
3371 self.obsolete(last_span, ObsoleteSyntax::OwnedPattern);
3373 id: ast::DUMMY_NODE_ID,
3378 token::BinOp(token::And) | token::AndAnd => {
3379 // parse &pat and &mut pat
3380 let lo = self.span.lo;
3382 let mutability = if self.eat_keyword(keywords::Mut) {
3387 let sub = self.parse_pat();
3388 pat = PatRegion(sub, mutability);
3389 hi = self.last_span.hi;
3391 id: ast::DUMMY_NODE_ID,
3396 token::OpenDelim(token::Paren) => {
3397 // parse (pat,pat,pat,...) as tuple
3399 if self.check(&token::CloseDelim(token::Paren)) {
3401 pat = PatTup(vec![]);
3403 let mut fields = vec!(self.parse_pat());
3404 if self.look_ahead(1, |t| *t != token::CloseDelim(token::Paren)) {
3405 while self.check(&token::Comma) {
3407 if self.check(&token::CloseDelim(token::Paren)) { break; }
3408 fields.push(self.parse_pat());
3411 if fields.len() == 1 { self.expect(&token::Comma); }
3412 self.expect(&token::CloseDelim(token::Paren));
3413 pat = PatTup(fields);
3415 hi = self.last_span.hi;
3417 id: ast::DUMMY_NODE_ID,
3422 token::OpenDelim(token::Bracket) => {
3423 // parse [pat,pat,...] as vector pattern
3425 let (before, slice, after) =
3426 self.parse_pat_vec_elements();
3428 self.expect(&token::CloseDelim(token::Bracket));
3429 pat = ast::PatVec(before, slice, after);
3430 hi = self.last_span.hi;
3432 id: ast::DUMMY_NODE_ID,
3439 // at this point, token != _, ~, &, &&, (, [
3441 if (!(self.token.is_ident() || self.token.is_path())
3442 && self.token != token::ModSep)
3443 || self.token.is_keyword(keywords::True)
3444 || self.token.is_keyword(keywords::False) {
3445 // Parse an expression pattern or exp .. exp.
3447 // These expressions are limited to literals (possibly
3448 // preceded by unary-minus) or identifiers.
3449 let val = self.parse_literal_maybe_minus();
3450 if (self.check(&token::DotDotDot)) &&
3451 self.look_ahead(1, |t| {
3452 *t != token::Comma && *t != token::CloseDelim(token::Bracket)
3455 let end = if self.token.is_ident() || self.token.is_path() {
3456 let path = self.parse_path(LifetimeAndTypesWithColons);
3457 let hi = self.span.hi;
3458 self.mk_expr(lo, hi, ExprPath(path))
3460 self.parse_literal_maybe_minus()
3462 pat = PatRange(val, end);
3466 } else if self.eat_keyword(keywords::Mut) {
3467 pat = self.parse_pat_ident(BindByValue(MutMutable));
3468 } else if self.eat_keyword(keywords::Ref) {
3470 let mutbl = self.parse_mutability();
3471 pat = self.parse_pat_ident(BindByRef(mutbl));
3472 } else if self.eat_keyword(keywords::Box) {
3475 // FIXME(#13910): Rename to `PatBox` and extend to full DST
3477 let sub = self.parse_pat();
3479 hi = self.last_span.hi;
3481 id: ast::DUMMY_NODE_ID,
3486 let can_be_enum_or_struct = self.look_ahead(1, |t| {
3488 token::OpenDelim(_) | token::Lt | token::ModSep => true,
3493 if self.look_ahead(1, |t| *t == token::DotDotDot) &&
3494 self.look_ahead(2, |t| {
3495 *t != token::Comma && *t != token::CloseDelim(token::Bracket)
3497 let start = self.parse_expr_res(RESTRICTION_NO_BAR_OP);
3498 self.eat(&token::DotDotDot);
3499 let end = self.parse_expr_res(RESTRICTION_NO_BAR_OP);
3500 pat = PatRange(start, end);
3501 } else if self.token.is_plain_ident() && !can_be_enum_or_struct {
3502 let id = self.parse_ident();
3503 let id_span = self.last_span;
3504 let pth1 = codemap::Spanned{span:id_span, node: id};
3505 if self.eat(&token::Not) {
3507 let delim = self.expect_open_delim();
3508 let tts = self.parse_seq_to_end(&token::CloseDelim(delim),
3510 |p| p.parse_token_tree());
3512 let mac = MacInvocTT(ident_to_path(id_span,id), tts, EMPTY_CTXT);
3513 pat = ast::PatMac(codemap::Spanned {node: mac, span: self.span});
3515 let sub = if self.eat(&token::At) {
3517 Some(self.parse_pat())
3522 pat = PatIdent(BindByValue(MutImmutable), pth1, sub);
3525 // parse an enum pat
3526 let enum_path = self.parse_path(LifetimeAndTypesWithColons);
3528 token::OpenDelim(token::Brace) => {
3531 self.parse_pat_fields();
3533 pat = PatStruct(enum_path, fields, etc);
3536 let mut args: Vec<P<Pat>> = Vec::new();
3538 token::OpenDelim(token::Paren) => {
3539 let is_dotdot = self.look_ahead(1, |t| {
3541 token::DotDot => true,
3546 // This is a "top constructor only" pat
3549 self.expect(&token::CloseDelim(token::Paren));
3550 pat = PatEnum(enum_path, None);
3552 args = self.parse_enum_variant_seq(
3553 &token::OpenDelim(token::Paren),
3554 &token::CloseDelim(token::Paren),
3555 seq_sep_trailing_allowed(token::Comma),
3558 pat = PatEnum(enum_path, Some(args));
3562 if !enum_path.global &&
3563 enum_path.segments.len() == 1 &&
3564 enum_path.segments[0].parameters.is_empty()
3566 // it could still be either an enum
3567 // or an identifier pattern, resolve
3568 // will sort it out:
3569 pat = PatIdent(BindByValue(MutImmutable),
3571 span: enum_path.span,
3572 node: enum_path.segments[0]
3576 pat = PatEnum(enum_path, Some(args));
3584 hi = self.last_span.hi;
3586 id: ast::DUMMY_NODE_ID,
3588 span: mk_sp(lo, hi),
3592 /// Parse ident or ident @ pat
3593 /// used by the copy foo and ref foo patterns to give a good
3594 /// error message when parsing mistakes like ref foo(a,b)
3595 fn parse_pat_ident(&mut self,
3596 binding_mode: ast::BindingMode)
3598 if !self.token.is_plain_ident() {
3599 let span = self.span;
3600 let tok_str = self.this_token_to_string();
3601 self.span_fatal(span,
3602 &format!("expected identifier, found `{}`", tok_str)[]);
3604 let ident = self.parse_ident();
3605 let last_span = self.last_span;
3606 let name = codemap::Spanned{span: last_span, node: ident};
3607 let sub = if self.eat(&token::At) {
3608 Some(self.parse_pat())
3613 // just to be friendly, if they write something like
3615 // we end up here with ( as the current token. This shortly
3616 // leads to a parse error. Note that if there is no explicit
3617 // binding mode then we do not end up here, because the lookahead
3618 // will direct us over to parse_enum_variant()
3619 if self.token == token::OpenDelim(token::Paren) {
3620 let last_span = self.last_span;
3623 "expected identifier, found enum pattern");
3626 PatIdent(binding_mode, name, sub)
3629 /// Parse a local variable declaration
3630 fn parse_local(&mut self) -> P<Local> {
3631 let lo = self.span.lo;
3632 let pat = self.parse_pat();
3635 if self.eat(&token::Colon) {
3636 ty = Some(self.parse_ty_sum());
3638 let init = self.parse_initializer();
3643 id: ast::DUMMY_NODE_ID,
3644 span: mk_sp(lo, self.last_span.hi),
3649 /// Parse a "let" stmt
3650 fn parse_let(&mut self) -> P<Decl> {
3651 let lo = self.span.lo;
3652 let local = self.parse_local();
3653 P(spanned(lo, self.last_span.hi, DeclLocal(local)))
3656 /// Parse a structure field
3657 fn parse_name_and_ty(&mut self, pr: Visibility,
3658 attrs: Vec<Attribute> ) -> StructField {
3659 let lo = self.span.lo;
3660 if !self.token.is_plain_ident() {
3661 self.fatal("expected ident");
3663 let name = self.parse_ident();
3664 self.expect(&token::Colon);
3665 let ty = self.parse_ty_sum();
3666 spanned(lo, self.last_span.hi, ast::StructField_ {
3667 kind: NamedField(name, pr),
3668 id: ast::DUMMY_NODE_ID,
3674 /// Get an expected item after attributes error message.
3675 fn expected_item_err(attrs: &[Attribute]) -> &'static str {
3676 match attrs.last() {
3677 Some(&Attribute { node: ast::Attribute_ { is_sugared_doc: true, .. }, .. }) => {
3678 "expected item after doc comment"
3680 _ => "expected item after attributes",
3684 /// Parse a statement. may include decl.
3685 /// Precondition: any attributes are parsed already
3686 pub fn parse_stmt(&mut self, item_attrs: Vec<Attribute>) -> P<Stmt> {
3687 maybe_whole!(self, NtStmt);
3689 fn check_expected_item(p: &mut Parser, attrs: &[Attribute]) {
3690 // If we have attributes then we should have an item
3691 if !attrs.is_empty() {
3692 let last_span = p.last_span;
3693 p.span_err(last_span, Parser::expected_item_err(attrs));
3697 let lo = self.span.lo;
3698 if self.token.is_keyword(keywords::Let) {
3699 check_expected_item(self, &item_attrs[]);
3700 self.expect_keyword(keywords::Let);
3701 let decl = self.parse_let();
3702 P(spanned(lo, decl.span.hi, StmtDecl(decl, ast::DUMMY_NODE_ID)))
3703 } else if self.token.is_ident()
3704 && !self.token.is_any_keyword()
3705 && self.look_ahead(1, |t| *t == token::Not) {
3706 // it's a macro invocation:
3708 check_expected_item(self, &item_attrs[]);
3710 // Potential trouble: if we allow macros with paths instead of
3711 // idents, we'd need to look ahead past the whole path here...
3712 let pth = self.parse_path(NoTypesAllowed);
3715 let id = match self.token {
3716 token::OpenDelim(_) => token::special_idents::invalid, // no special identifier
3717 _ => self.parse_ident(),
3720 // check that we're pointing at delimiters (need to check
3721 // again after the `if`, because of `parse_ident`
3722 // consuming more tokens).
3723 let delim = match self.token {
3724 token::OpenDelim(delim) => delim,
3726 // we only expect an ident if we didn't parse one
3728 let ident_str = if id.name == token::special_idents::invalid.name {
3733 let tok_str = self.this_token_to_string();
3734 self.fatal(&format!("expected {}`(` or `{{`, found `{}`",
3740 let tts = self.parse_unspanned_seq(
3741 &token::OpenDelim(delim),
3742 &token::CloseDelim(delim),
3744 |p| p.parse_token_tree()
3746 let hi = self.span.hi;
3748 let style = if delim == token::Brace {
3751 MacStmtWithoutBraces
3754 if id.name == token::special_idents::invalid.name {
3757 StmtMac(P(spanned(lo,
3759 MacInvocTT(pth, tts, EMPTY_CTXT))),
3762 // if it has a special ident, it's definitely an item
3764 // Require a semicolon or braces.
3765 if style != MacStmtWithBraces {
3766 if !self.eat(&token::Semi) {
3767 let last_span = self.last_span;
3768 self.span_err(last_span,
3769 "macros that expand to items must \
3770 either be surrounded with braces or \
3771 followed by a semicolon");
3774 P(spanned(lo, hi, StmtDecl(
3775 P(spanned(lo, hi, DeclItem(
3777 lo, hi, id /*id is good here*/,
3778 ItemMac(spanned(lo, hi, MacInvocTT(pth, tts, EMPTY_CTXT))),
3779 Inherited, Vec::new(/*no attrs*/))))),
3780 ast::DUMMY_NODE_ID)))
3783 let found_attrs = !item_attrs.is_empty();
3784 let item_err = Parser::expected_item_err(&item_attrs[]);
3785 match self.parse_item_or_view_item(item_attrs, false) {
3788 let decl = P(spanned(lo, hi, DeclItem(i)));
3789 P(spanned(lo, hi, StmtDecl(decl, ast::DUMMY_NODE_ID)))
3791 IoviViewItem(vi) => {
3792 self.span_fatal(vi.span,
3793 "view items must be declared at the top of the block");
3795 IoviForeignItem(_) => {
3796 self.fatal("foreign items are not allowed here");
3800 let last_span = self.last_span;
3801 self.span_err(last_span, item_err);
3804 // Remainder are line-expr stmts.
3805 let e = self.parse_expr_res(RESTRICTION_STMT_EXPR);
3806 P(spanned(lo, e.span.hi, StmtExpr(e, ast::DUMMY_NODE_ID)))
3812 /// Is this expression a successfully-parsed statement?
3813 fn expr_is_complete(&mut self, e: &Expr) -> bool {
3814 self.restrictions.contains(RESTRICTION_STMT_EXPR) &&
3815 !classify::expr_requires_semi_to_be_stmt(e)
3818 /// Parse a block. No inner attrs are allowed.
3819 pub fn parse_block(&mut self) -> P<Block> {
3820 maybe_whole!(no_clone self, NtBlock);
3822 let lo = self.span.lo;
3824 if !self.eat(&token::OpenDelim(token::Brace)) {
3826 let tok = self.this_token_to_string();
3827 self.span_fatal_help(sp,
3828 &format!("expected `{{`, found `{}`", tok)[],
3829 "place this code inside a block");
3832 return self.parse_block_tail_(lo, DefaultBlock, Vec::new());
3835 /// Parse a block. Inner attrs are allowed.
3836 fn parse_inner_attrs_and_block(&mut self)
3837 -> (Vec<Attribute> , P<Block>) {
3839 maybe_whole!(pair_empty self, NtBlock);
3841 let lo = self.span.lo;
3842 self.expect(&token::OpenDelim(token::Brace));
3843 let (inner, next) = self.parse_inner_attrs_and_next();
3845 (inner, self.parse_block_tail_(lo, DefaultBlock, next))
3848 /// Precondition: already parsed the '{' or '#{'
3849 /// I guess that also means "already parsed the 'impure'" if
3850 /// necessary, and this should take a qualifier.
3851 /// Some blocks start with "#{"...
3852 fn parse_block_tail(&mut self, lo: BytePos, s: BlockCheckMode) -> P<Block> {
3853 self.parse_block_tail_(lo, s, Vec::new())
3856 /// Parse the rest of a block expression or function body
3857 fn parse_block_tail_(&mut self, lo: BytePos, s: BlockCheckMode,
3858 first_item_attrs: Vec<Attribute> ) -> P<Block> {
3859 let mut stmts = Vec::new();
3860 let mut expr = None;
3862 // wouldn't it be more uniform to parse view items only, here?
3863 let ParsedItemsAndViewItems {
3868 } = self.parse_items_and_view_items(first_item_attrs,
3871 for item in items.into_iter() {
3872 let span = item.span;
3873 let decl = P(spanned(span.lo, span.hi, DeclItem(item)));
3874 stmts.push(P(spanned(span.lo, span.hi, StmtDecl(decl, ast::DUMMY_NODE_ID))));
3877 let mut attributes_box = attrs_remaining;
3879 while self.token != token::CloseDelim(token::Brace) {
3880 // parsing items even when they're not allowed lets us give
3881 // better error messages and recover more gracefully.
3882 attributes_box.push_all(&self.parse_outer_attributes()[]);
3885 if !attributes_box.is_empty() {
3886 let last_span = self.last_span;
3887 self.span_err(last_span,
3888 Parser::expected_item_err(&attributes_box[]));
3889 attributes_box = Vec::new();
3891 self.bump(); // empty
3893 token::CloseDelim(token::Brace) => {
3894 // fall through and out.
3897 let stmt = self.parse_stmt(attributes_box);
3898 attributes_box = Vec::new();
3899 stmt.and_then(|Spanned {node, span}| match node {
3900 StmtExpr(e, stmt_id) => {
3901 self.handle_expression_like_statement(e,
3907 StmtMac(mac, MacStmtWithoutBraces) => {
3908 // statement macro without braces; might be an
3909 // expr depending on whether a semicolon follows
3912 stmts.push(P(Spanned {
3914 MacStmtWithSemicolon),
3920 let e = self.mk_mac_expr(span.lo,
3922 mac.and_then(|m| m.node));
3923 let e = self.parse_dot_or_call_expr_with(e);
3924 let e = self.parse_more_binops(e, 0);
3925 let e = self.parse_assign_expr_with(e);
3926 self.handle_expression_like_statement(
3935 StmtMac(m, style) => {
3936 // statement macro; might be an expr
3939 stmts.push(P(Spanned {
3941 MacStmtWithSemicolon),
3946 token::CloseDelim(token::Brace) => {
3947 // if a block ends in `m!(arg)` without
3948 // a `;`, it must be an expr
3950 self.mk_mac_expr(span.lo,
3952 m.and_then(|x| x.node)));
3955 stmts.push(P(Spanned {
3956 node: StmtMac(m, style),
3962 _ => { // all other kinds of statements:
3963 if classify::stmt_ends_with_semi(&node) {
3964 self.commit_stmt_expecting(token::Semi);
3967 stmts.push(P(Spanned {
3977 if !attributes_box.is_empty() {
3978 let last_span = self.last_span;
3979 self.span_err(last_span,
3980 Parser::expected_item_err(&attributes_box[]));
3983 let hi = self.span.hi;
3986 view_items: view_items,
3989 id: ast::DUMMY_NODE_ID,
3991 span: mk_sp(lo, hi),
3995 fn handle_expression_like_statement(
4000 stmts: &mut Vec<P<Stmt>>,
4001 last_block_expr: &mut Option<P<Expr>>) {
4002 // expression without semicolon
4003 if classify::expr_requires_semi_to_be_stmt(&*e) {
4004 // Just check for errors and recover; do not eat semicolon yet.
4005 self.commit_stmt(&[],
4006 &[token::Semi, token::CloseDelim(token::Brace)]);
4012 let span_with_semi = Span {
4014 hi: self.last_span.hi,
4015 expn_id: span.expn_id,
4017 stmts.push(P(Spanned {
4018 node: StmtSemi(e, stmt_id),
4019 span: span_with_semi,
4022 token::CloseDelim(token::Brace) => *last_block_expr = Some(e),
4024 stmts.push(P(Spanned {
4025 node: StmtExpr(e, stmt_id),
4032 // Parses a sequence of bounds if a `:` is found,
4033 // otherwise returns empty list.
4034 fn parse_colon_then_ty_param_bounds(&mut self,
4035 mode: BoundParsingMode)
4036 -> OwnedSlice<TyParamBound>
4038 if !self.eat(&token::Colon) {
4041 self.parse_ty_param_bounds(mode)
4045 // matches bounds = ( boundseq )?
4046 // where boundseq = ( polybound + boundseq ) | polybound
4047 // and polybound = ( 'for' '<' 'region '>' )? bound
4048 // and bound = 'region | trait_ref
4049 fn parse_ty_param_bounds(&mut self,
4050 mode: BoundParsingMode)
4051 -> OwnedSlice<TyParamBound>
4053 let mut result = vec!();
4055 let question_span = self.span;
4056 let ate_question = self.eat(&token::Question);
4058 token::Lifetime(lifetime) => {
4060 self.span_err(question_span,
4061 "`?` may only modify trait bounds, not lifetime bounds");
4063 result.push(RegionTyParamBound(ast::Lifetime {
4064 id: ast::DUMMY_NODE_ID,
4070 token::ModSep | token::Ident(..) => {
4071 let poly_trait_ref = self.parse_poly_trait_ref();
4072 let modifier = if ate_question {
4073 if mode == BoundParsingMode::Modified {
4074 TraitBoundModifier::Maybe
4076 self.span_err(question_span,
4078 TraitBoundModifier::None
4081 TraitBoundModifier::None
4083 result.push(TraitTyParamBound(poly_trait_ref, modifier))
4088 if !self.eat(&token::BinOp(token::Plus)) {
4093 return OwnedSlice::from_vec(result);
4096 fn trait_ref_from_ident(ident: Ident, span: Span) -> TraitRef {
4097 let segment = ast::PathSegment {
4099 parameters: ast::PathParameters::none()
4101 let path = ast::Path {
4104 segments: vec![segment],
4108 ref_id: ast::DUMMY_NODE_ID,
4112 /// Matches typaram = (unbound `?`)? IDENT (`?` unbound)? optbounds ( EQ ty )?
4113 fn parse_ty_param(&mut self) -> TyParam {
4114 // This is a bit hacky. Currently we are only interested in a single
4115 // unbound, and it may only be `Sized`. To avoid backtracking and other
4116 // complications, we parse an ident, then check for `?`. If we find it,
4117 // we use the ident as the unbound, otherwise, we use it as the name of
4118 // type param. Even worse, we need to check for `?` before or after the
4120 let mut span = self.span;
4121 let mut ident = self.parse_ident();
4122 let mut unbound = None;
4123 if self.eat(&token::Question) {
4124 let tref = Parser::trait_ref_from_ident(ident, span);
4125 unbound = Some(tref);
4127 ident = self.parse_ident();
4128 self.obsolete(span, ObsoleteSyntax::Sized);
4131 let mut bounds = self.parse_colon_then_ty_param_bounds(BoundParsingMode::Modified);
4132 if let Some(unbound) = unbound {
4133 let mut bounds_as_vec = bounds.into_vec();
4134 bounds_as_vec.push(TraitTyParamBound(PolyTraitRef { bound_lifetimes: vec![],
4135 trait_ref: unbound },
4136 TraitBoundModifier::Maybe));
4137 bounds = OwnedSlice::from_vec(bounds_as_vec);
4140 let default = if self.check(&token::Eq) {
4142 Some(self.parse_ty_sum())
4148 id: ast::DUMMY_NODE_ID,
4155 /// Parse a set of optional generic type parameter declarations. Where
4156 /// clauses are not parsed here, and must be added later via
4157 /// `parse_where_clause()`.
4159 /// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
4160 /// | ( < lifetimes , typaramseq ( , )? > )
4161 /// where typaramseq = ( typaram ) | ( typaram , typaramseq )
4162 pub fn parse_generics(&mut self) -> ast::Generics {
4163 if self.eat(&token::Lt) {
4164 let lifetime_defs = self.parse_lifetime_defs();
4165 let mut seen_default = false;
4166 let ty_params = self.parse_seq_to_gt(Some(token::Comma), |p| {
4167 p.forbid_lifetime();
4168 let ty_param = p.parse_ty_param();
4169 if ty_param.default.is_some() {
4170 seen_default = true;
4171 } else if seen_default {
4172 let last_span = p.last_span;
4173 p.span_err(last_span,
4174 "type parameters with a default must be trailing");
4179 lifetimes: lifetime_defs,
4180 ty_params: ty_params,
4181 where_clause: WhereClause {
4182 id: ast::DUMMY_NODE_ID,
4183 predicates: Vec::new(),
4187 ast_util::empty_generics()
4191 fn parse_generic_values_after_lt(&mut self)
4192 -> (Vec<ast::Lifetime>, Vec<P<Ty>>, Vec<P<TypeBinding>>) {
4193 let lifetimes = self.parse_lifetimes(token::Comma);
4195 // First parse types.
4196 let (types, returned) = self.parse_seq_to_gt_or_return(
4199 p.forbid_lifetime();
4200 if p.look_ahead(1, |t| t == &token::Eq) {
4203 Some(p.parse_ty_sum())
4208 // If we found the `>`, don't continue.
4210 return (lifetimes, types.into_vec(), Vec::new());
4213 // Then parse type bindings.
4214 let bindings = self.parse_seq_to_gt(
4217 p.forbid_lifetime();
4219 let ident = p.parse_ident();
4220 let found_eq = p.eat(&token::Eq);
4223 p.span_warn(span, "whoops, no =?");
4225 let ty = p.parse_ty();
4227 let span = mk_sp(lo, hi);
4228 return P(TypeBinding{id: ast::DUMMY_NODE_ID,
4235 (lifetimes, types.into_vec(), bindings.into_vec())
4238 fn forbid_lifetime(&mut self) {
4239 if self.token.is_lifetime() {
4240 let span = self.span;
4241 self.span_fatal(span, "lifetime parameters must be declared \
4242 prior to type parameters");
4246 /// Parses an optional `where` clause and places it in `generics`.
4249 /// where T : Trait<U, V> + 'b, 'a : 'b
4251 fn parse_where_clause(&mut self, generics: &mut ast::Generics) {
4252 if !self.eat_keyword(keywords::Where) {
4256 let mut parsed_something = false;
4258 let lo = self.span.lo;
4260 token::OpenDelim(token::Brace) => {
4264 token::Lifetime(..) => {
4265 let bounded_lifetime =
4266 self.parse_lifetime();
4268 self.eat(&token::Colon);
4271 self.parse_lifetimes(token::BinOp(token::Plus));
4273 let hi = self.span.hi;
4274 let span = mk_sp(lo, hi);
4276 generics.where_clause.predicates.push(ast::WherePredicate::RegionPredicate(
4277 ast::WhereRegionPredicate {
4279 lifetime: bounded_lifetime,
4284 parsed_something = true;
4288 let bounded_ty = self.parse_ty();
4290 if self.eat(&token::Colon) {
4291 let bounds = self.parse_ty_param_bounds(BoundParsingMode::Bare);
4292 let hi = self.span.hi;
4293 let span = mk_sp(lo, hi);
4295 if bounds.len() == 0 {
4297 "each predicate in a `where` clause must have \
4298 at least one bound in it");
4301 generics.where_clause.predicates.push(ast::WherePredicate::BoundPredicate(
4302 ast::WhereBoundPredicate {
4304 bounded_ty: bounded_ty,
4308 parsed_something = true;
4309 } else if self.eat(&token::Eq) {
4310 // let ty = self.parse_ty();
4311 let hi = self.span.hi;
4312 let span = mk_sp(lo, hi);
4313 // generics.where_clause.predicates.push(
4314 // ast::WherePredicate::EqPredicate(ast::WhereEqPredicate {
4315 // id: ast::DUMMY_NODE_ID,
4317 // path: panic!("NYI"), //bounded_ty,
4320 // parsed_something = true;
4323 "equality constraints are not yet supported \
4324 in where clauses (#20041)");
4326 let last_span = self.last_span;
4327 self.span_err(last_span,
4328 "unexpected token in `where` clause");
4333 if !self.eat(&token::Comma) {
4338 if !parsed_something {
4339 let last_span = self.last_span;
4340 self.span_err(last_span,
4341 "a `where` clause must have at least one predicate \
4346 fn parse_fn_args(&mut self, named_args: bool, allow_variadic: bool)
4347 -> (Vec<Arg> , bool) {
4349 let mut args: Vec<Option<Arg>> =
4350 self.parse_unspanned_seq(
4351 &token::OpenDelim(token::Paren),
4352 &token::CloseDelim(token::Paren),
4353 seq_sep_trailing_allowed(token::Comma),
4355 if p.token == token::DotDotDot {
4358 if p.token != token::CloseDelim(token::Paren) {
4361 "`...` must be last in argument list for variadic function");
4366 "only foreign functions are allowed to be variadic");
4370 Some(p.parse_arg_general(named_args))
4375 let variadic = match args.pop() {
4378 // Need to put back that last arg
4385 if variadic && args.is_empty() {
4387 "variadic function must be declared with at least one named argument");
4390 let args = args.into_iter().map(|x| x.unwrap()).collect();
4395 /// Parse the argument list and result type of a function declaration
4396 pub fn parse_fn_decl(&mut self, allow_variadic: bool) -> P<FnDecl> {
4398 let (args, variadic) = self.parse_fn_args(true, allow_variadic);
4399 let ret_ty = self.parse_ret_ty();
4408 fn is_self_ident(&mut self) -> bool {
4410 token::Ident(id, token::Plain) => id.name == special_idents::self_.name,
4415 fn expect_self_ident(&mut self) -> ast::Ident {
4417 token::Ident(id, token::Plain) if id.name == special_idents::self_.name => {
4422 let token_str = self.this_token_to_string();
4423 self.fatal(&format!("expected `self`, found `{}`",
4429 /// Parse the argument list and result type of a function
4430 /// that may have a self type.
4431 fn parse_fn_decl_with_self<F>(&mut self, parse_arg_fn: F) -> (ExplicitSelf, P<FnDecl>) where
4432 F: FnMut(&mut Parser) -> Arg,
4434 fn maybe_parse_borrowed_explicit_self(this: &mut Parser)
4435 -> ast::ExplicitSelf_ {
4436 // The following things are possible to see here:
4441 // fn(&'lt mut self)
4443 // We already know that the current token is `&`.
4445 if this.look_ahead(1, |t| t.is_keyword(keywords::Self)) {
4447 SelfRegion(None, MutImmutable, this.expect_self_ident())
4448 } else if this.look_ahead(1, |t| t.is_mutability()) &&
4449 this.look_ahead(2, |t| t.is_keyword(keywords::Self)) {
4451 let mutability = this.parse_mutability();
4452 SelfRegion(None, mutability, this.expect_self_ident())
4453 } else if this.look_ahead(1, |t| t.is_lifetime()) &&
4454 this.look_ahead(2, |t| t.is_keyword(keywords::Self)) {
4456 let lifetime = this.parse_lifetime();
4457 SelfRegion(Some(lifetime), MutImmutable, this.expect_self_ident())
4458 } else if this.look_ahead(1, |t| t.is_lifetime()) &&
4459 this.look_ahead(2, |t| t.is_mutability()) &&
4460 this.look_ahead(3, |t| t.is_keyword(keywords::Self)) {
4462 let lifetime = this.parse_lifetime();
4463 let mutability = this.parse_mutability();
4464 SelfRegion(Some(lifetime), mutability, this.expect_self_ident())
4470 self.expect(&token::OpenDelim(token::Paren));
4472 // A bit of complexity and lookahead is needed here in order to be
4473 // backwards compatible.
4474 let lo = self.span.lo;
4475 let mut self_ident_lo = self.span.lo;
4476 let mut self_ident_hi = self.span.hi;
4478 let mut mutbl_self = MutImmutable;
4479 let explicit_self = match self.token {
4480 token::BinOp(token::And) => {
4481 let eself = maybe_parse_borrowed_explicit_self(self);
4482 self_ident_lo = self.last_span.lo;
4483 self_ident_hi = self.last_span.hi;
4487 // We need to make sure it isn't a type
4488 if self.look_ahead(1, |t| t.is_keyword(keywords::Self)) {
4490 drop(self.expect_self_ident());
4491 let last_span = self.last_span;
4492 self.obsolete(last_span, ObsoleteSyntax::OwnedSelf)
4496 token::BinOp(token::Star) => {
4497 // Possibly "*self" or "*mut self" -- not supported. Try to avoid
4498 // emitting cryptic "unexpected token" errors.
4500 let _mutability = if self.token.is_mutability() {
4501 self.parse_mutability()
4505 if self.is_self_ident() {
4506 let span = self.span;
4507 self.span_err(span, "cannot pass self by unsafe pointer");
4510 // error case, making bogus self ident:
4511 SelfValue(special_idents::self_)
4513 token::Ident(..) => {
4514 if self.is_self_ident() {
4515 let self_ident = self.expect_self_ident();
4517 // Determine whether this is the fully explicit form, `self:
4519 if self.eat(&token::Colon) {
4520 SelfExplicit(self.parse_ty_sum(), self_ident)
4522 SelfValue(self_ident)
4524 } else if self.token.is_mutability() &&
4525 self.look_ahead(1, |t| t.is_keyword(keywords::Self)) {
4526 mutbl_self = self.parse_mutability();
4527 let self_ident = self.expect_self_ident();
4529 // Determine whether this is the fully explicit form,
4531 if self.eat(&token::Colon) {
4532 SelfExplicit(self.parse_ty_sum(), self_ident)
4534 SelfValue(self_ident)
4536 } else if self.token.is_mutability() &&
4537 self.look_ahead(1, |t| *t == token::Tilde) &&
4538 self.look_ahead(2, |t| t.is_keyword(keywords::Self)) {
4539 mutbl_self = self.parse_mutability();
4541 drop(self.expect_self_ident());
4542 let last_span = self.last_span;
4543 self.obsolete(last_span, ObsoleteSyntax::OwnedSelf);
4552 let explicit_self_sp = mk_sp(self_ident_lo, self_ident_hi);
4554 // shared fall-through for the three cases below. borrowing prevents simply
4555 // writing this as a closure
4556 macro_rules! parse_remaining_arguments {
4559 // If we parsed a self type, expect a comma before the argument list.
4563 let sep = seq_sep_trailing_allowed(token::Comma);
4564 let mut fn_inputs = self.parse_seq_to_before_end(
4565 &token::CloseDelim(token::Paren),
4569 fn_inputs.insert(0, Arg::new_self(explicit_self_sp, mutbl_self, $self_id));
4572 token::CloseDelim(token::Paren) => {
4573 vec!(Arg::new_self(explicit_self_sp, mutbl_self, $self_id))
4576 let token_str = self.this_token_to_string();
4577 self.fatal(&format!("expected `,` or `)`, found `{}`",
4584 let fn_inputs = match explicit_self {
4586 let sep = seq_sep_trailing_allowed(token::Comma);
4587 self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)
4589 SelfValue(id) => parse_remaining_arguments!(id),
4590 SelfRegion(_,_,id) => parse_remaining_arguments!(id),
4591 SelfExplicit(_,id) => parse_remaining_arguments!(id),
4595 self.expect(&token::CloseDelim(token::Paren));
4597 let hi = self.span.hi;
4599 let ret_ty = self.parse_ret_ty();
4601 let fn_decl = P(FnDecl {
4607 (spanned(lo, hi, explicit_self), fn_decl)
4610 // parse the |arg, arg| header on a lambda
4611 fn parse_fn_block_decl(&mut self)
4612 -> (P<FnDecl>, Option<UnboxedClosureKind>) {
4613 let (optional_unboxed_closure_kind, inputs_captures) = {
4614 if self.eat(&token::OrOr) {
4617 self.expect(&token::BinOp(token::Or));
4618 let optional_unboxed_closure_kind =
4619 self.parse_optional_unboxed_closure_kind();
4620 let args = self.parse_seq_to_before_end(
4621 &token::BinOp(token::Or),
4622 seq_sep_trailing_allowed(token::Comma),
4623 |p| p.parse_fn_block_arg()
4626 (optional_unboxed_closure_kind, args)
4629 let output = if self.check(&token::RArrow) {
4633 id: ast::DUMMY_NODE_ID,
4640 inputs: inputs_captures,
4643 }), optional_unboxed_closure_kind)
4646 /// Parses the `(arg, arg) -> return_type` header on a procedure.
4647 fn parse_proc_decl(&mut self) -> P<FnDecl> {
4649 self.parse_unspanned_seq(&token::OpenDelim(token::Paren),
4650 &token::CloseDelim(token::Paren),
4651 seq_sep_trailing_allowed(token::Comma),
4652 |p| p.parse_fn_block_arg());
4654 let output = if self.check(&token::RArrow) {
4658 id: ast::DUMMY_NODE_ID,
4671 /// Parse the name and optional generic types of a function header.
4672 fn parse_fn_header(&mut self) -> (Ident, ast::Generics) {
4673 let id = self.parse_ident();
4674 let generics = self.parse_generics();
4678 fn mk_item(&mut self, lo: BytePos, hi: BytePos, ident: Ident,
4679 node: Item_, vis: Visibility,
4680 attrs: Vec<Attribute>) -> P<Item> {
4684 id: ast::DUMMY_NODE_ID,
4691 /// Parse an item-position function declaration.
4692 fn parse_item_fn(&mut self, unsafety: Unsafety, abi: abi::Abi) -> ItemInfo {
4693 let (ident, mut generics) = self.parse_fn_header();
4694 let decl = self.parse_fn_decl(false);
4695 self.parse_where_clause(&mut generics);
4696 let (inner_attrs, body) = self.parse_inner_attrs_and_block();
4697 (ident, ItemFn(decl, unsafety, abi, generics, body), Some(inner_attrs))
4700 /// Parse a method in a trait impl
4701 pub fn parse_method_with_outer_attributes(&mut self) -> P<Method> {
4702 let attrs = self.parse_outer_attributes();
4703 let visa = self.parse_visibility();
4704 self.parse_method(attrs, visa)
4707 /// Parse a method in a trait impl, starting with `attrs` attributes.
4708 pub fn parse_method(&mut self,
4709 attrs: Vec<Attribute>,
4712 let lo = self.span.lo;
4714 // code copied from parse_macro_use_or_failure... abstraction!
4715 let (method_, hi, new_attrs) = {
4716 if !self.token.is_any_keyword()
4717 && self.look_ahead(1, |t| *t == token::Not)
4718 && (self.look_ahead(2, |t| *t == token::OpenDelim(token::Paren))
4719 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))) {
4721 let pth = self.parse_path(NoTypesAllowed);
4722 self.expect(&token::Not);
4724 // eat a matched-delimiter token tree:
4725 let delim = self.expect_open_delim();
4726 let tts = self.parse_seq_to_end(&token::CloseDelim(delim),
4728 |p| p.parse_token_tree());
4729 let m_ = ast::MacInvocTT(pth, tts, EMPTY_CTXT);
4730 let m: ast::Mac = codemap::Spanned { node: m_,
4731 span: mk_sp(self.span.lo,
4733 if delim != token::Brace {
4734 self.expect(&token::Semi)
4736 (ast::MethMac(m), self.span.hi, attrs)
4738 let unsafety = self.parse_unsafety();
4739 let abi = if self.eat_keyword(keywords::Extern) {
4740 self.parse_opt_abi().unwrap_or(abi::C)
4744 self.expect_keyword(keywords::Fn);
4745 let ident = self.parse_ident();
4746 let mut generics = self.parse_generics();
4747 let (explicit_self, decl) = self.parse_fn_decl_with_self(|p| {
4750 self.parse_where_clause(&mut generics);
4751 let (inner_attrs, body) = self.parse_inner_attrs_and_block();
4752 let body_span = body.span;
4753 let mut new_attrs = attrs;
4754 new_attrs.push_all(&inner_attrs[]);
4755 (ast::MethDecl(ident,
4763 body_span.hi, new_attrs)
4768 id: ast::DUMMY_NODE_ID,
4769 span: mk_sp(lo, hi),
4774 /// Parse trait Foo { ... }
4775 fn parse_item_trait(&mut self, unsafety: Unsafety) -> ItemInfo {
4776 let ident = self.parse_ident();
4777 let mut tps = self.parse_generics();
4778 let unbound = self.parse_for_sized();
4780 // Parse supertrait bounds.
4781 let mut bounds = self.parse_colon_then_ty_param_bounds(BoundParsingMode::Bare);
4783 if let Some(unbound) = unbound {
4784 let mut bounds_as_vec = bounds.into_vec();
4785 bounds_as_vec.push(TraitTyParamBound(PolyTraitRef { bound_lifetimes: vec![],
4786 trait_ref: unbound },
4787 TraitBoundModifier::Maybe));
4788 bounds = OwnedSlice::from_vec(bounds_as_vec);
4791 self.parse_where_clause(&mut tps);
4793 let meths = self.parse_trait_items();
4794 (ident, ItemTrait(unsafety, tps, bounds, meths), None)
4797 fn parse_impl_items(&mut self) -> (Vec<ImplItem>, Vec<Attribute>) {
4798 let mut impl_items = Vec::new();
4799 self.expect(&token::OpenDelim(token::Brace));
4800 let (inner_attrs, mut method_attrs) =
4801 self.parse_inner_attrs_and_next();
4803 method_attrs.extend(self.parse_outer_attributes().into_iter());
4804 if method_attrs.is_empty() && self.eat(&token::CloseDelim(token::Brace)) {
4808 let vis = self.parse_visibility();
4809 if self.eat_keyword(keywords::Type) {
4810 impl_items.push(TypeImplItem(P(self.parse_typedef(
4814 impl_items.push(MethodImplItem(self.parse_method(
4818 method_attrs = vec![];
4820 (impl_items, inner_attrs)
4823 /// Parses two variants (with the region/type params always optional):
4824 /// impl<T> Foo { ... }
4825 /// impl<T> ToString for ~[T] { ... }
4826 fn parse_item_impl(&mut self, unsafety: ast::Unsafety) -> ItemInfo {
4827 // First, parse type parameters if necessary.
4828 let mut generics = self.parse_generics();
4830 // Special case: if the next identifier that follows is '(', don't
4831 // allow this to be parsed as a trait.
4832 let could_be_trait = self.token != token::OpenDelim(token::Paren);
4834 let neg_span = self.span;
4835 let polarity = if self.eat(&token::Not) {
4836 ast::ImplPolarity::Negative
4838 ast::ImplPolarity::Positive
4842 let mut ty = self.parse_ty_sum();
4844 // Parse traits, if necessary.
4845 let opt_trait = if could_be_trait && self.eat_keyword(keywords::For) {
4846 // New-style trait. Reinterpret the type as a trait.
4847 let opt_trait_ref = match ty.node {
4848 TyPath(ref path, node_id) => {
4850 path: (*path).clone(),
4855 self.span_err(ty.span, "not a trait");
4860 ty = self.parse_ty_sum();
4864 ast::ImplPolarity::Negative => {
4865 // This is a negated type implementation
4866 // `impl !MyType {}`, which is not allowed.
4867 self.span_err(neg_span, "inherent implementation can't be negated");
4874 self.parse_where_clause(&mut generics);
4875 let (impl_items, attrs) = self.parse_impl_items();
4877 let ident = ast_util::impl_pretty_name(&opt_trait, &*ty);
4880 ItemImpl(unsafety, polarity, generics, opt_trait, ty, impl_items),
4884 /// Parse a::B<String,int>
4885 fn parse_trait_ref(&mut self) -> TraitRef {
4887 path: self.parse_path(LifetimeAndTypesWithoutColons),
4888 ref_id: ast::DUMMY_NODE_ID,
4892 fn parse_late_bound_lifetime_defs(&mut self) -> Vec<ast::LifetimeDef> {
4893 if self.eat_keyword(keywords::For) {
4894 self.expect(&token::Lt);
4895 let lifetime_defs = self.parse_lifetime_defs();
4903 /// Parse for<'l> a::B<String,int>
4904 fn parse_poly_trait_ref(&mut self) -> PolyTraitRef {
4905 let lifetime_defs = self.parse_late_bound_lifetime_defs();
4908 bound_lifetimes: lifetime_defs,
4909 trait_ref: self.parse_trait_ref()
4913 /// Parse struct Foo { ... }
4914 fn parse_item_struct(&mut self) -> ItemInfo {
4915 let class_name = self.parse_ident();
4916 let mut generics = self.parse_generics();
4918 if self.eat(&token::Colon) {
4919 let ty = self.parse_ty_sum();
4920 self.span_err(ty.span, "`virtual` structs have been removed from the language");
4923 // There is a special case worth noting here, as reported in issue #17904.
4924 // If we are parsing a tuple struct it is the case that the where clause
4925 // should follow the field list. Like so:
4927 // struct Foo<T>(T) where T: Copy;
4929 // If we are parsing a normal record-style struct it is the case
4930 // that the where clause comes before the body, and after the generics.
4931 // So if we look ahead and see a brace or a where-clause we begin
4932 // parsing a record style struct.
4934 // Otherwise if we look ahead and see a paren we parse a tuple-style
4937 let (fields, ctor_id) = if self.token.is_keyword(keywords::Where) {
4938 self.parse_where_clause(&mut generics);
4939 if self.eat(&token::Semi) {
4940 // If we see a: `struct Foo<T> where T: Copy;` style decl.
4941 (Vec::new(), Some(ast::DUMMY_NODE_ID))
4943 // If we see: `struct Foo<T> where T: Copy { ... }`
4944 (self.parse_record_struct_body(&class_name), None)
4946 // No `where` so: `struct Foo<T>;`
4947 } else if self.eat(&token::Semi) {
4948 (Vec::new(), Some(ast::DUMMY_NODE_ID))
4949 // Record-style struct definition
4950 } else if self.token == token::OpenDelim(token::Brace) {
4951 let fields = self.parse_record_struct_body(&class_name);
4953 // Tuple-style struct definition with optional where-clause.
4955 let fields = self.parse_tuple_struct_body(&class_name, &mut generics);
4956 (fields, Some(ast::DUMMY_NODE_ID))
4960 ItemStruct(P(ast::StructDef {
4967 pub fn parse_record_struct_body(&mut self, class_name: &ast::Ident) -> Vec<StructField> {
4968 let mut fields = Vec::new();
4969 if self.eat(&token::OpenDelim(token::Brace)) {
4970 while self.token != token::CloseDelim(token::Brace) {
4971 fields.push(self.parse_struct_decl_field(true));
4974 if fields.len() == 0 {
4975 self.fatal(&format!("unit-like struct definition should be \
4976 written as `struct {};`",
4977 token::get_ident(class_name.clone()))[]);
4982 let token_str = self.this_token_to_string();
4983 self.fatal(&format!("expected `where`, or `{}` after struct \
4984 name, found `{}`", "{",
4991 pub fn parse_tuple_struct_body(&mut self,
4992 class_name: &ast::Ident,
4993 generics: &mut ast::Generics)
4994 -> Vec<StructField> {
4995 // This is the case where we find `struct Foo<T>(T) where T: Copy;`
4996 if self.check(&token::OpenDelim(token::Paren)) {
4997 let fields = self.parse_unspanned_seq(
4998 &token::OpenDelim(token::Paren),
4999 &token::CloseDelim(token::Paren),
5000 seq_sep_trailing_allowed(token::Comma),
5002 let attrs = p.parse_outer_attributes();
5004 let struct_field_ = ast::StructField_ {
5005 kind: UnnamedField(p.parse_visibility()),
5006 id: ast::DUMMY_NODE_ID,
5007 ty: p.parse_ty_sum(),
5010 spanned(lo, p.span.hi, struct_field_)
5013 if fields.len() == 0 {
5014 self.fatal(&format!("unit-like struct definition should be \
5015 written as `struct {};`",
5016 token::get_ident(class_name.clone()))[]);
5019 self.parse_where_clause(generics);
5020 self.expect(&token::Semi);
5022 // This is the case where we just see struct Foo<T> where T: Copy;
5023 } else if self.token.is_keyword(keywords::Where) {
5024 self.parse_where_clause(generics);
5025 self.expect(&token::Semi);
5027 // This case is where we see: `struct Foo<T>;`
5029 let token_str = self.this_token_to_string();
5030 self.fatal(&format!("expected `where`, `{}`, `(`, or `;` after struct \
5031 name, found `{}`", "{", token_str)[]);
5035 /// Parse a structure field declaration
5036 pub fn parse_single_struct_field(&mut self,
5038 attrs: Vec<Attribute> )
5040 let a_var = self.parse_name_and_ty(vis, attrs);
5045 token::CloseDelim(token::Brace) => {}
5047 let span = self.span;
5048 let token_str = self.this_token_to_string();
5049 self.span_fatal_help(span,
5050 &format!("expected `,`, or `}}`, found `{}`",
5052 "struct fields should be separated by commas")
5058 /// Parse an element of a struct definition
5059 fn parse_struct_decl_field(&mut self, allow_pub: bool) -> StructField {
5061 let attrs = self.parse_outer_attributes();
5063 if self.eat_keyword(keywords::Pub) {
5065 let span = self.last_span;
5066 self.span_err(span, "`pub` is not allowed here");
5068 return self.parse_single_struct_field(Public, attrs);
5071 return self.parse_single_struct_field(Inherited, attrs);
5074 /// Parse visibility: PUB, PRIV, or nothing
5075 fn parse_visibility(&mut self) -> Visibility {
5076 if self.eat_keyword(keywords::Pub) { Public }
5080 fn parse_for_sized(&mut self) -> Option<ast::TraitRef> {
5081 // FIXME, this should really use TraitBoundModifier, but it will get
5082 // re-jigged shortly in any case, so leaving the hacky version for now.
5083 if self.eat_keyword(keywords::For) {
5084 let span = self.span;
5086 let mut ate_question = false;
5087 if self.eat(&token::Question) {
5088 ate_question = true;
5090 let ident = self.parse_ident();
5091 if self.eat(&token::Question) {
5096 ate_question = true;
5100 "expected `?Sized` after `for` in trait item");
5103 let _tref = Parser::trait_ref_from_ident(ident, span);
5105 self.obsolete(span, ObsoleteSyntax::ForSized);
5113 /// Given a termination token and a vector of already-parsed
5114 /// attributes (of length 0 or 1), parse all of the items in a module
5115 fn parse_mod_items(&mut self,
5117 first_item_attrs: Vec<Attribute>,
5120 // parse all of the items up to closing or an attribute.
5121 // view items are legal here.
5122 let ParsedItemsAndViewItems {
5125 items: starting_items,
5127 } = self.parse_items_and_view_items(first_item_attrs, true, true);
5128 let mut items: Vec<P<Item>> = starting_items;
5129 let attrs_remaining_len = attrs_remaining.len();
5131 // don't think this other loop is even necessary....
5133 let mut first = true;
5134 while self.token != term {
5135 let mut attrs = self.parse_outer_attributes();
5137 let mut tmp = attrs_remaining.clone();
5138 tmp.push_all(&attrs[]);
5142 debug!("parse_mod_items: parse_item_or_view_item(attrs={:?})",
5144 match self.parse_item_or_view_item(attrs,
5145 true /* macros allowed */) {
5146 IoviItem(item) => items.push(item),
5147 IoviViewItem(view_item) => {
5148 self.span_fatal(view_item.span,
5149 "view items must be declared at the top of \
5153 let token_str = self.this_token_to_string();
5154 self.fatal(&format!("expected item, found `{}`",
5160 if first && attrs_remaining_len > 0u {
5161 // We parsed attributes for the first item but didn't find it
5162 let last_span = self.last_span;
5163 self.span_err(last_span,
5164 Parser::expected_item_err(&attrs_remaining[]));
5168 inner: mk_sp(inner_lo, self.span.lo),
5169 view_items: view_items,
5174 fn parse_item_const(&mut self, m: Option<Mutability>) -> ItemInfo {
5175 let id = self.parse_ident();
5176 self.expect(&token::Colon);
5177 let ty = self.parse_ty_sum();
5178 self.expect(&token::Eq);
5179 let e = self.parse_expr();
5180 self.commit_expr_expecting(&*e, token::Semi);
5181 let item = match m {
5182 Some(m) => ItemStatic(ty, m, e),
5183 None => ItemConst(ty, e),
5188 /// Parse a `mod <foo> { ... }` or `mod <foo>;` item
5189 fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> ItemInfo {
5190 let id_span = self.span;
5191 let id = self.parse_ident();
5192 if self.check(&token::Semi) {
5194 // This mod is in an external file. Let's go get it!
5195 let (m, attrs) = self.eval_src_mod(id, outer_attrs, id_span);
5196 (id, m, Some(attrs))
5198 self.push_mod_path(id, outer_attrs);
5199 self.expect(&token::OpenDelim(token::Brace));
5200 let mod_inner_lo = self.span.lo;
5201 let old_owns_directory = self.owns_directory;
5202 self.owns_directory = true;
5203 let (inner, next) = self.parse_inner_attrs_and_next();
5204 let m = self.parse_mod_items(token::CloseDelim(token::Brace), next, mod_inner_lo);
5205 self.expect(&token::CloseDelim(token::Brace));
5206 self.owns_directory = old_owns_directory;
5207 self.pop_mod_path();
5208 (id, ItemMod(m), Some(inner))
5212 fn push_mod_path(&mut self, id: Ident, attrs: &[Attribute]) {
5213 let default_path = self.id_to_interned_str(id);
5214 let file_path = match ::attr::first_attr_value_str_by_name(attrs,
5217 None => default_path,
5219 self.mod_path_stack.push(file_path)
5222 fn pop_mod_path(&mut self) {
5223 self.mod_path_stack.pop().unwrap();
5226 /// Read a module from a source file.
5227 fn eval_src_mod(&mut self,
5229 outer_attrs: &[ast::Attribute],
5231 -> (ast::Item_, Vec<ast::Attribute> ) {
5232 let mut prefix = Path::new(self.sess.span_diagnostic.cm.span_to_filename(self.span));
5234 let mod_path = Path::new(".").join_many(&self.mod_path_stack[]);
5235 let dir_path = prefix.join(&mod_path);
5236 let mod_string = token::get_ident(id);
5237 let (file_path, owns_directory) = match ::attr::first_attr_value_str_by_name(
5238 outer_attrs, "path") {
5239 Some(d) => (dir_path.join(d), true),
5241 let mod_name = mod_string.get().to_string();
5242 let default_path_str = format!("{}.rs", mod_name);
5243 let secondary_path_str = format!("{}/mod.rs", mod_name);
5244 let default_path = dir_path.join(&default_path_str[]);
5245 let secondary_path = dir_path.join(&secondary_path_str[]);
5246 let default_exists = default_path.exists();
5247 let secondary_exists = secondary_path.exists();
5249 if !self.owns_directory {
5250 self.span_err(id_sp,
5251 "cannot declare a new module at this location");
5252 let this_module = match self.mod_path_stack.last() {
5253 Some(name) => name.get().to_string(),
5254 None => self.root_module_name.as_ref().unwrap().clone(),
5256 self.span_note(id_sp,
5257 &format!("maybe move this module `{0}` \
5258 to its own directory via \
5261 if default_exists || secondary_exists {
5262 self.span_note(id_sp,
5263 &format!("... or maybe `use` the module \
5264 `{}` instead of possibly \
5268 self.abort_if_errors();
5271 match (default_exists, secondary_exists) {
5272 (true, false) => (default_path, false),
5273 (false, true) => (secondary_path, true),
5275 self.span_fatal_help(id_sp,
5276 &format!("file not found for module `{}`",
5278 &format!("name the file either {} or {} inside \
5279 the directory {:?}",
5282 dir_path.display())[]);
5285 self.span_fatal_help(
5287 &format!("file for module `{}` found at both {} \
5291 secondary_path_str)[],
5292 "delete or rename one of them to remove the ambiguity");
5298 self.eval_src_mod_from_path(file_path, owns_directory,
5299 mod_string.get().to_string(), id_sp)
5302 fn eval_src_mod_from_path(&mut self,
5304 owns_directory: bool,
5306 id_sp: Span) -> (ast::Item_, Vec<ast::Attribute> ) {
5307 let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
5308 match included_mod_stack.iter().position(|p| *p == path) {
5310 let mut err = String::from_str("circular modules: ");
5311 let len = included_mod_stack.len();
5312 for p in included_mod_stack.slice(i, len).iter() {
5313 err.push_str(&p.display().as_cow()[]);
5314 err.push_str(" -> ");
5316 err.push_str(&path.display().as_cow()[]);
5317 self.span_fatal(id_sp, &err[]);
5321 included_mod_stack.push(path.clone());
5322 drop(included_mod_stack);
5325 new_sub_parser_from_file(self.sess,
5331 let mod_inner_lo = p0.span.lo;
5332 let (mod_attrs, next) = p0.parse_inner_attrs_and_next();
5333 let first_item_outer_attrs = next;
5334 let m0 = p0.parse_mod_items(token::Eof, first_item_outer_attrs, mod_inner_lo);
5335 self.sess.included_mod_stack.borrow_mut().pop();
5336 return (ast::ItemMod(m0), mod_attrs);
5339 /// Parse a function declaration from a foreign module
5340 fn parse_item_foreign_fn(&mut self, vis: ast::Visibility,
5341 attrs: Vec<Attribute>) -> P<ForeignItem> {
5342 let lo = self.span.lo;
5343 self.expect_keyword(keywords::Fn);
5345 let (ident, mut generics) = self.parse_fn_header();
5346 let decl = self.parse_fn_decl(true);
5347 self.parse_where_clause(&mut generics);
5348 let hi = self.span.hi;
5349 self.expect(&token::Semi);
5350 P(ast::ForeignItem {
5353 node: ForeignItemFn(decl, generics),
5354 id: ast::DUMMY_NODE_ID,
5355 span: mk_sp(lo, hi),
5360 /// Parse a static item from a foreign module
5361 fn parse_item_foreign_static(&mut self, vis: ast::Visibility,
5362 attrs: Vec<Attribute>) -> P<ForeignItem> {
5363 let lo = self.span.lo;
5365 self.expect_keyword(keywords::Static);
5366 let mutbl = self.eat_keyword(keywords::Mut);
5368 let ident = self.parse_ident();
5369 self.expect(&token::Colon);
5370 let ty = self.parse_ty_sum();
5371 let hi = self.span.hi;
5372 self.expect(&token::Semi);
5376 node: ForeignItemStatic(ty, mutbl),
5377 id: ast::DUMMY_NODE_ID,
5378 span: mk_sp(lo, hi),
5383 /// At this point, this is essentially a wrapper for
5384 /// parse_foreign_items.
5385 fn parse_foreign_mod_items(&mut self,
5387 first_item_attrs: Vec<Attribute> )
5389 let ParsedItemsAndViewItems {
5394 } = self.parse_foreign_items(first_item_attrs, true);
5395 if !attrs_remaining.is_empty() {
5396 let last_span = self.last_span;
5397 self.span_err(last_span,
5398 Parser::expected_item_err(&attrs_remaining[]));
5400 assert!(self.token == token::CloseDelim(token::Brace));
5403 view_items: view_items,
5404 items: foreign_items
5408 /// Parse extern crate links
5412 /// extern crate url;
5413 /// extern crate foo = "bar"; //deprecated
5414 /// extern crate "bar" as foo;
5415 fn parse_item_extern_crate(&mut self,
5417 visibility: Visibility,
5418 attrs: Vec<Attribute> )
5421 let span = self.span;
5422 let (maybe_path, ident) = match self.token {
5423 token::Ident(..) => {
5424 let the_ident = self.parse_ident();
5425 let path = if self.token == token::Eq {
5427 let path = self.parse_str();
5428 let span = self.span;
5429 self.obsolete(span, ObsoleteSyntax::ExternCrateRenaming);
5431 } else if self.eat_keyword(keywords::As) {
5432 // skip the ident if there is one
5433 if self.token.is_ident() { self.bump(); }
5435 self.span_err(span, "expected `;`, found `as`");
5436 self.span_help(span,
5437 &format!("perhaps you meant to enclose the crate name `{}` in \
5439 the_ident.as_str())[]);
5444 self.expect(&token::Semi);
5447 token::Literal(token::Str_(..), suf) | token::Literal(token::StrRaw(..), suf) => {
5449 self.expect_no_suffix(sp, "extern crate name", suf);
5450 // forgo the internal suffix check of `parse_str` to
5451 // avoid repeats (this unwrap will always succeed due
5452 // to the restriction of the `match`)
5453 let (s, style, _) = self.parse_optional_str().unwrap();
5454 self.expect_keyword(keywords::As);
5455 let the_ident = self.parse_ident();
5456 self.expect(&token::Semi);
5457 (Some((s, style)), the_ident)
5460 let span = self.span;
5461 let token_str = self.this_token_to_string();
5462 self.span_fatal(span,
5463 &format!("expected extern crate name but \
5469 IoviViewItem(ast::ViewItem {
5470 node: ViewItemExternCrate(ident, maybe_path, ast::DUMMY_NODE_ID),
5473 span: mk_sp(lo, self.last_span.hi)
5477 /// Parse `extern` for foreign ABIs
5480 /// `extern` is expected to have been
5481 /// consumed before calling this method
5487 fn parse_item_foreign_mod(&mut self,
5489 opt_abi: Option<abi::Abi>,
5490 visibility: Visibility,
5491 attrs: Vec<Attribute> )
5494 self.expect(&token::OpenDelim(token::Brace));
5496 let abi = opt_abi.unwrap_or(abi::C);
5498 let (inner, next) = self.parse_inner_attrs_and_next();
5499 let m = self.parse_foreign_mod_items(abi, next);
5500 self.expect(&token::CloseDelim(token::Brace));
5502 let last_span = self.last_span;
5503 let item = self.mk_item(lo,
5505 special_idents::invalid,
5508 maybe_append(attrs, Some(inner)));
5509 return IoviItem(item);
5512 /// Parse type Foo = Bar;
5513 fn parse_item_type(&mut self) -> ItemInfo {
5514 let ident = self.parse_ident();
5515 let mut tps = self.parse_generics();
5516 self.parse_where_clause(&mut tps);
5517 self.expect(&token::Eq);
5518 let ty = self.parse_ty_sum();
5519 self.expect(&token::Semi);
5520 (ident, ItemTy(ty, tps), None)
5523 /// Parse a structure-like enum variant definition
5524 /// this should probably be renamed or refactored...
5525 fn parse_struct_def(&mut self) -> P<StructDef> {
5526 let mut fields: Vec<StructField> = Vec::new();
5527 while self.token != token::CloseDelim(token::Brace) {
5528 fields.push(self.parse_struct_decl_field(false));
5538 /// Parse the part of an "enum" decl following the '{'
5539 fn parse_enum_def(&mut self, _generics: &ast::Generics) -> EnumDef {
5540 let mut variants = Vec::new();
5541 let mut all_nullary = true;
5542 let mut any_disr = None;
5543 while self.token != token::CloseDelim(token::Brace) {
5544 let variant_attrs = self.parse_outer_attributes();
5545 let vlo = self.span.lo;
5547 let vis = self.parse_visibility();
5551 let mut args = Vec::new();
5552 let mut disr_expr = None;
5553 ident = self.parse_ident();
5554 if self.eat(&token::OpenDelim(token::Brace)) {
5555 // Parse a struct variant.
5556 all_nullary = false;
5557 let start_span = self.span;
5558 let struct_def = self.parse_struct_def();
5559 if struct_def.fields.len() == 0 {
5560 self.span_err(start_span,
5561 &format!("unit-like struct variant should be written \
5562 without braces, as `{},`",
5563 token::get_ident(ident))[]);
5565 kind = StructVariantKind(struct_def);
5566 } else if self.check(&token::OpenDelim(token::Paren)) {
5567 all_nullary = false;
5568 let arg_tys = self.parse_enum_variant_seq(
5569 &token::OpenDelim(token::Paren),
5570 &token::CloseDelim(token::Paren),
5571 seq_sep_trailing_allowed(token::Comma),
5572 |p| p.parse_ty_sum()
5574 for ty in arg_tys.into_iter() {
5575 args.push(ast::VariantArg {
5577 id: ast::DUMMY_NODE_ID,
5580 kind = TupleVariantKind(args);
5581 } else if self.eat(&token::Eq) {
5582 disr_expr = Some(self.parse_expr());
5583 any_disr = disr_expr.as_ref().map(|expr| expr.span);
5584 kind = TupleVariantKind(args);
5586 kind = TupleVariantKind(Vec::new());
5589 let vr = ast::Variant_ {
5591 attrs: variant_attrs,
5593 id: ast::DUMMY_NODE_ID,
5594 disr_expr: disr_expr,
5597 variants.push(P(spanned(vlo, self.last_span.hi, vr)));
5599 if !self.eat(&token::Comma) { break; }
5601 self.expect(&token::CloseDelim(token::Brace));
5603 Some(disr_span) if !all_nullary =>
5604 self.span_err(disr_span,
5605 "discriminator values can only be used with a c-like enum"),
5609 ast::EnumDef { variants: variants }
5612 /// Parse an "enum" declaration
5613 fn parse_item_enum(&mut self) -> ItemInfo {
5614 let id = self.parse_ident();
5615 let mut generics = self.parse_generics();
5616 self.parse_where_clause(&mut generics);
5617 self.expect(&token::OpenDelim(token::Brace));
5619 let enum_definition = self.parse_enum_def(&generics);
5620 (id, ItemEnum(enum_definition, generics), None)
5623 fn fn_expr_lookahead(tok: &token::Token) -> bool {
5625 token::OpenDelim(token::Paren) | token::At | token::Tilde | token::BinOp(_) => true,
5630 /// Parses a string as an ABI spec on an extern type or module. Consumes
5631 /// the `extern` keyword, if one is found.
5632 fn parse_opt_abi(&mut self) -> Option<abi::Abi> {
5634 token::Literal(token::Str_(s), suf) | token::Literal(token::StrRaw(s, _), suf) => {
5636 self.expect_no_suffix(sp, "ABI spec", suf);
5638 let the_string = s.as_str();
5639 match abi::lookup(the_string) {
5640 Some(abi) => Some(abi),
5642 let last_span = self.last_span;
5645 &format!("illegal ABI: expected one of [{}], \
5647 abi::all_names().connect(", "),
5658 /// Parse one of the items or view items allowed by the
5659 /// flags; on failure, return IoviNone.
5660 /// NB: this function no longer parses the items inside an
5662 fn parse_item_or_view_item(&mut self,
5663 attrs: Vec<Attribute> ,
5664 macros_allowed: bool)
5666 let nt_item = match self.token {
5667 token::Interpolated(token::NtItem(ref item)) => {
5668 Some((**item).clone())
5675 let mut attrs = attrs;
5676 mem::swap(&mut item.attrs, &mut attrs);
5677 item.attrs.extend(attrs.into_iter());
5678 return IoviItem(P(item));
5683 let lo = self.span.lo;
5685 let visibility = self.parse_visibility();
5687 // must be a view item:
5688 if self.eat_keyword(keywords::Use) {
5689 // USE ITEM (IoviViewItem)
5690 let view_item = self.parse_use();
5691 self.expect(&token::Semi);
5692 return IoviViewItem(ast::ViewItem {
5696 span: mk_sp(lo, self.last_span.hi)
5699 // either a view item or an item:
5700 if self.eat_keyword(keywords::Extern) {
5701 let next_is_mod = self.eat_keyword(keywords::Mod);
5703 if next_is_mod || self.eat_keyword(keywords::Crate) {
5705 let last_span = self.last_span;
5706 self.span_err(mk_sp(lo, last_span.hi),
5707 &format!("`extern mod` is obsolete, use \
5708 `extern crate` instead \
5709 to refer to external \
5712 return self.parse_item_extern_crate(lo, visibility, attrs);
5715 let opt_abi = self.parse_opt_abi();
5717 if self.eat_keyword(keywords::Fn) {
5718 // EXTERN FUNCTION ITEM
5719 let abi = opt_abi.unwrap_or(abi::C);
5720 let (ident, item_, extra_attrs) =
5721 self.parse_item_fn(Unsafety::Normal, abi);
5722 let last_span = self.last_span;
5723 let item = self.mk_item(lo,
5728 maybe_append(attrs, extra_attrs));
5729 return IoviItem(item);
5730 } else if self.check(&token::OpenDelim(token::Brace)) {
5731 return self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs);
5734 let span = self.span;
5735 let token_str = self.this_token_to_string();
5736 self.span_fatal(span,
5737 &format!("expected `{}` or `fn`, found `{}`", "{",
5741 if self.eat_keyword(keywords::Virtual) {
5742 let span = self.span;
5743 self.span_err(span, "`virtual` structs have been removed from the language");
5746 // the rest are all guaranteed to be items:
5747 if self.token.is_keyword(keywords::Static) {
5750 let m = if self.eat_keyword(keywords::Mut) {MutMutable} else {MutImmutable};
5751 let (ident, item_, extra_attrs) = self.parse_item_const(Some(m));
5752 let last_span = self.last_span;
5753 let item = self.mk_item(lo,
5758 maybe_append(attrs, extra_attrs));
5759 return IoviItem(item);
5761 if self.token.is_keyword(keywords::Const) {
5764 if self.eat_keyword(keywords::Mut) {
5765 let last_span = self.last_span;
5766 self.span_err(last_span, "const globals cannot be mutable");
5767 self.span_help(last_span, "did you mean to declare a static?");
5769 let (ident, item_, extra_attrs) = self.parse_item_const(None);
5770 let last_span = self.last_span;
5771 let item = self.mk_item(lo,
5776 maybe_append(attrs, extra_attrs));
5777 return IoviItem(item);
5779 if self.token.is_keyword(keywords::Unsafe) &&
5780 self.look_ahead(1u, |t| t.is_keyword(keywords::Trait))
5782 // UNSAFE TRAIT ITEM
5783 self.expect_keyword(keywords::Unsafe);
5784 self.expect_keyword(keywords::Trait);
5785 let (ident, item_, extra_attrs) =
5786 self.parse_item_trait(ast::Unsafety::Unsafe);
5787 let last_span = self.last_span;
5788 let item = self.mk_item(lo,
5793 maybe_append(attrs, extra_attrs));
5794 return IoviItem(item);
5796 if self.token.is_keyword(keywords::Unsafe) &&
5797 self.look_ahead(1u, |t| t.is_keyword(keywords::Impl))
5800 self.expect_keyword(keywords::Unsafe);
5801 self.expect_keyword(keywords::Impl);
5802 let (ident, item_, extra_attrs) = self.parse_item_impl(ast::Unsafety::Unsafe);
5803 let last_span = self.last_span;
5804 let item = self.mk_item(lo,
5809 maybe_append(attrs, extra_attrs));
5810 return IoviItem(item);
5812 if self.token.is_keyword(keywords::Fn) &&
5813 self.look_ahead(1, |f| !Parser::fn_expr_lookahead(f)) {
5816 let (ident, item_, extra_attrs) =
5817 self.parse_item_fn(Unsafety::Normal, abi::Rust);
5818 let last_span = self.last_span;
5819 let item = self.mk_item(lo,
5824 maybe_append(attrs, extra_attrs));
5825 return IoviItem(item);
5827 if self.token.is_keyword(keywords::Unsafe)
5828 && self.look_ahead(1u, |t| *t != token::OpenDelim(token::Brace)) {
5829 // UNSAFE FUNCTION ITEM
5831 let abi = if self.eat_keyword(keywords::Extern) {
5832 self.parse_opt_abi().unwrap_or(abi::C)
5836 self.expect_keyword(keywords::Fn);
5837 let (ident, item_, extra_attrs) =
5838 self.parse_item_fn(Unsafety::Unsafe, abi);
5839 let last_span = self.last_span;
5840 let item = self.mk_item(lo,
5845 maybe_append(attrs, extra_attrs));
5846 return IoviItem(item);
5848 if self.eat_keyword(keywords::Mod) {
5850 let (ident, item_, extra_attrs) =
5851 self.parse_item_mod(&attrs[]);
5852 let last_span = self.last_span;
5853 let item = self.mk_item(lo,
5858 maybe_append(attrs, extra_attrs));
5859 return IoviItem(item);
5861 if self.eat_keyword(keywords::Type) {
5863 let (ident, item_, extra_attrs) = self.parse_item_type();
5864 let last_span = self.last_span;
5865 let item = self.mk_item(lo,
5870 maybe_append(attrs, extra_attrs));
5871 return IoviItem(item);
5873 if self.eat_keyword(keywords::Enum) {
5875 let (ident, item_, extra_attrs) = self.parse_item_enum();
5876 let last_span = self.last_span;
5877 let item = self.mk_item(lo,
5882 maybe_append(attrs, extra_attrs));
5883 return IoviItem(item);
5885 if self.eat_keyword(keywords::Trait) {
5887 let (ident, item_, extra_attrs) =
5888 self.parse_item_trait(ast::Unsafety::Normal);
5889 let last_span = self.last_span;
5890 let item = self.mk_item(lo,
5895 maybe_append(attrs, extra_attrs));
5896 return IoviItem(item);
5898 if self.eat_keyword(keywords::Impl) {
5900 let (ident, item_, extra_attrs) = self.parse_item_impl(ast::Unsafety::Normal);
5901 let last_span = self.last_span;
5902 let item = self.mk_item(lo,
5907 maybe_append(attrs, extra_attrs));
5908 return IoviItem(item);
5910 if self.eat_keyword(keywords::Struct) {
5912 let (ident, item_, extra_attrs) = self.parse_item_struct();
5913 let last_span = self.last_span;
5914 let item = self.mk_item(lo,
5919 maybe_append(attrs, extra_attrs));
5920 return IoviItem(item);
5922 self.parse_macro_use_or_failure(attrs,macros_allowed,lo,visibility)
5925 /// Parse a foreign item; on failure, return IoviNone.
5926 fn parse_foreign_item(&mut self,
5927 attrs: Vec<Attribute> ,
5928 macros_allowed: bool)
5930 maybe_whole!(iovi self, NtItem);
5931 let lo = self.span.lo;
5933 let visibility = self.parse_visibility();
5935 if self.token.is_keyword(keywords::Static) {
5936 // FOREIGN STATIC ITEM
5937 let item = self.parse_item_foreign_static(visibility, attrs);
5938 return IoviForeignItem(item);
5940 if self.token.is_keyword(keywords::Fn) || self.token.is_keyword(keywords::Unsafe) {
5941 // FOREIGN FUNCTION ITEM
5942 let item = self.parse_item_foreign_fn(visibility, attrs);
5943 return IoviForeignItem(item);
5945 self.parse_macro_use_or_failure(attrs,macros_allowed,lo,visibility)
5948 /// This is the fall-through for parsing items.
5949 fn parse_macro_use_or_failure(
5951 attrs: Vec<Attribute> ,
5952 macros_allowed: bool,
5954 visibility: Visibility
5955 ) -> ItemOrViewItem {
5956 if macros_allowed && !self.token.is_any_keyword()
5957 && self.look_ahead(1, |t| *t == token::Not)
5958 && (self.look_ahead(2, |t| t.is_plain_ident())
5959 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Paren))
5960 || self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace))) {
5961 // MACRO INVOCATION ITEM
5964 let pth = self.parse_path(NoTypesAllowed);
5965 self.expect(&token::Not);
5967 // a 'special' identifier (like what `macro_rules!` uses)
5968 // is optional. We should eventually unify invoc syntax
5970 let id = if self.token.is_plain_ident() {
5973 token::special_idents::invalid // no special identifier
5975 // eat a matched-delimiter token tree:
5976 let delim = self.expect_open_delim();
5977 let tts = self.parse_seq_to_end(&token::CloseDelim(delim),
5979 |p| p.parse_token_tree());
5980 // single-variant-enum... :
5981 let m = ast::MacInvocTT(pth, tts, EMPTY_CTXT);
5982 let m: ast::Mac = codemap::Spanned { node: m,
5983 span: mk_sp(self.span.lo,
5986 if delim != token::Brace {
5987 if !self.eat(&token::Semi) {
5988 let last_span = self.last_span;
5989 self.span_err(last_span,
5990 "macros that expand to items must either \
5991 be surrounded with braces or followed by \
5996 let item_ = ItemMac(m);
5997 let last_span = self.last_span;
5998 let item = self.mk_item(lo,
6004 return IoviItem(item);
6007 // FAILURE TO PARSE ITEM
6011 let last_span = self.last_span;
6012 self.span_fatal(last_span, "unmatched visibility `pub`");
6015 return IoviNone(attrs);
6018 pub fn parse_item_with_outer_attributes(&mut self) -> Option<P<Item>> {
6019 let attrs = self.parse_outer_attributes();
6020 self.parse_item(attrs)
6023 pub fn parse_item(&mut self, attrs: Vec<Attribute>) -> Option<P<Item>> {
6024 match self.parse_item_or_view_item(attrs, true) {
6025 IoviNone(_) => None,
6027 self.fatal("view items are not allowed here"),
6028 IoviForeignItem(_) =>
6029 self.fatal("foreign items are not allowed here"),
6030 IoviItem(item) => Some(item)
6034 /// Parse a ViewItem, e.g. `use foo::bar` or `extern crate foo`
6035 pub fn parse_view_item(&mut self, attrs: Vec<Attribute>) -> ViewItem {
6036 match self.parse_item_or_view_item(attrs, false) {
6037 IoviViewItem(vi) => vi,
6038 _ => self.fatal("expected `use` or `extern crate`"),
6042 /// Parse, e.g., "use a::b::{z,y}"
6043 fn parse_use(&mut self) -> ViewItem_ {
6044 return ViewItemUse(self.parse_view_path());
6048 /// Matches view_path : MOD? non_global_path as IDENT
6049 /// | MOD? non_global_path MOD_SEP LBRACE RBRACE
6050 /// | MOD? non_global_path MOD_SEP LBRACE ident_seq RBRACE
6051 /// | MOD? non_global_path MOD_SEP STAR
6052 /// | MOD? non_global_path
6053 fn parse_view_path(&mut self) -> P<ViewPath> {
6054 let lo = self.span.lo;
6056 // Allow a leading :: because the paths are absolute either way.
6057 // This occurs with "use $crate::..." in macros.
6058 self.eat(&token::ModSep);
6060 if self.check(&token::OpenDelim(token::Brace)) {
6062 let idents = self.parse_unspanned_seq(
6063 &token::OpenDelim(token::Brace),
6064 &token::CloseDelim(token::Brace),
6065 seq_sep_trailing_allowed(token::Comma),
6066 |p| p.parse_path_list_item());
6067 let path = ast::Path {
6068 span: mk_sp(lo, self.span.hi),
6070 segments: Vec::new()
6072 return P(spanned(lo, self.span.hi,
6073 ViewPathList(path, idents, ast::DUMMY_NODE_ID)));
6076 let first_ident = self.parse_ident();
6077 let mut path = vec!(first_ident);
6082 let path_lo = self.span.lo;
6083 path = vec!(self.parse_ident());
6084 while self.check(&token::ModSep) {
6086 let id = self.parse_ident();
6089 let span = mk_sp(path_lo, self.span.hi);
6090 self.obsolete(span, ObsoleteSyntax::ImportRenaming);
6091 let path = ast::Path {
6094 segments: path.into_iter().map(|identifier| {
6096 identifier: identifier,
6097 parameters: ast::PathParameters::none(),
6101 return P(spanned(lo, self.span.hi,
6102 ViewPathSimple(first_ident, path,
6103 ast::DUMMY_NODE_ID)));
6107 // foo::bar or foo::{a,b,c} or foo::*
6108 while self.check(&token::ModSep) {
6112 token::Ident(i, _) => {
6117 // foo::bar::{a,b,c}
6118 token::OpenDelim(token::Brace) => {
6119 let idents = self.parse_unspanned_seq(
6120 &token::OpenDelim(token::Brace),
6121 &token::CloseDelim(token::Brace),
6122 seq_sep_trailing_allowed(token::Comma),
6123 |p| p.parse_path_list_item()
6125 let path = ast::Path {
6126 span: mk_sp(lo, self.span.hi),
6128 segments: path.into_iter().map(|identifier| {
6130 identifier: identifier,
6131 parameters: ast::PathParameters::none(),
6135 return P(spanned(lo, self.span.hi,
6136 ViewPathList(path, idents, ast::DUMMY_NODE_ID)));
6140 token::BinOp(token::Star) => {
6142 let path = ast::Path {
6143 span: mk_sp(lo, self.span.hi),
6145 segments: path.into_iter().map(|identifier| {
6147 identifier: identifier,
6148 parameters: ast::PathParameters::none(),
6152 return P(spanned(lo, self.span.hi,
6153 ViewPathGlob(path, ast::DUMMY_NODE_ID)));
6162 let mut rename_to = path[path.len() - 1u];
6163 let path = ast::Path {
6164 span: mk_sp(lo, self.last_span.hi),
6166 segments: path.into_iter().map(|identifier| {
6168 identifier: identifier,
6169 parameters: ast::PathParameters::none(),
6173 if self.eat_keyword(keywords::As) {
6174 rename_to = self.parse_ident()
6178 ViewPathSimple(rename_to, path, ast::DUMMY_NODE_ID)))
6181 /// Parses a sequence of items. Stops when it finds program
6182 /// text that can't be parsed as an item
6183 /// - mod_items uses extern_mod_allowed = true
6184 /// - block_tail_ uses extern_mod_allowed = false
6185 fn parse_items_and_view_items(&mut self,
6186 first_item_attrs: Vec<Attribute> ,
6187 mut extern_mod_allowed: bool,
6188 macros_allowed: bool)
6189 -> ParsedItemsAndViewItems {
6190 let mut attrs = first_item_attrs;
6191 attrs.push_all(&self.parse_outer_attributes()[]);
6192 // First, parse view items.
6193 let mut view_items : Vec<ast::ViewItem> = Vec::new();
6194 let mut items = Vec::new();
6196 // I think this code would probably read better as a single
6197 // loop with a mutable three-state-variable (for extern crates,
6198 // view items, and regular items) ... except that because
6199 // of macros, I'd like to delay that entire check until later.
6201 match self.parse_item_or_view_item(attrs, macros_allowed) {
6202 IoviNone(attrs) => {
6203 return ParsedItemsAndViewItems {
6204 attrs_remaining: attrs,
6205 view_items: view_items,
6207 foreign_items: Vec::new()
6210 IoviViewItem(view_item) => {
6211 match view_item.node {
6212 ViewItemUse(..) => {
6213 // `extern crate` must precede `use`.
6214 extern_mod_allowed = false;
6216 ViewItemExternCrate(..) if !extern_mod_allowed => {
6217 self.span_err(view_item.span,
6218 "\"extern crate\" declarations are \
6221 ViewItemExternCrate(..) => {}
6223 view_items.push(view_item);
6227 attrs = self.parse_outer_attributes();
6230 IoviForeignItem(_) => {
6234 attrs = self.parse_outer_attributes();
6237 // Next, parse items.
6239 match self.parse_item_or_view_item(attrs, macros_allowed) {
6240 IoviNone(returned_attrs) => {
6241 attrs = returned_attrs;
6244 IoviViewItem(view_item) => {
6245 attrs = self.parse_outer_attributes();
6246 self.span_err(view_item.span,
6247 "`use` and `extern crate` declarations must precede items");
6250 attrs = self.parse_outer_attributes();
6253 IoviForeignItem(_) => {
6259 ParsedItemsAndViewItems {
6260 attrs_remaining: attrs,
6261 view_items: view_items,
6263 foreign_items: Vec::new()
6267 /// Parses a sequence of foreign items. Stops when it finds program
6268 /// text that can't be parsed as an item
6269 fn parse_foreign_items(&mut self, first_item_attrs: Vec<Attribute> ,
6270 macros_allowed: bool)
6271 -> ParsedItemsAndViewItems {
6272 let mut attrs = first_item_attrs;
6273 attrs.push_all(&self.parse_outer_attributes()[]);
6274 let mut foreign_items = Vec::new();
6276 match self.parse_foreign_item(attrs, macros_allowed) {
6277 IoviNone(returned_attrs) => {
6278 if self.check(&token::CloseDelim(token::Brace)) {
6279 attrs = returned_attrs;
6284 IoviViewItem(view_item) => {
6285 // I think this can't occur:
6286 self.span_err(view_item.span,
6287 "`use` and `extern crate` declarations must precede items");
6290 // FIXME #5668: this will occur for a macro invocation:
6291 self.span_fatal(item.span, "macros cannot expand to foreign items");
6293 IoviForeignItem(foreign_item) => {
6294 foreign_items.push(foreign_item);
6297 attrs = self.parse_outer_attributes();
6300 ParsedItemsAndViewItems {
6301 attrs_remaining: attrs,
6302 view_items: Vec::new(),
6304 foreign_items: foreign_items
6308 /// Parses a source module as a crate. This is the main
6309 /// entry point for the parser.
6310 pub fn parse_crate_mod(&mut self) -> Crate {
6311 let lo = self.span.lo;
6312 // parse the crate's inner attrs, maybe (oops) one
6313 // of the attrs of an item:
6314 let (inner, next) = self.parse_inner_attrs_and_next();
6315 let first_item_outer_attrs = next;
6316 // parse the items inside the crate:
6317 let m = self.parse_mod_items(token::Eof, first_item_outer_attrs, lo);
6322 config: self.cfg.clone(),
6323 span: mk_sp(lo, self.span.lo),
6324 exported_macros: Vec::new(),
6328 pub fn parse_optional_str(&mut self)
6329 -> Option<(InternedString, ast::StrStyle, Option<ast::Name>)> {
6330 let ret = match self.token {
6331 token::Literal(token::Str_(s), suf) => {
6332 (self.id_to_interned_str(s.ident()), ast::CookedStr, suf)
6334 token::Literal(token::StrRaw(s, n), suf) => {
6335 (self.id_to_interned_str(s.ident()), ast::RawStr(n), suf)
6343 pub fn parse_str(&mut self) -> (InternedString, StrStyle) {
6344 match self.parse_optional_str() {
6345 Some((s, style, suf)) => {
6346 let sp = self.last_span;
6347 self.expect_no_suffix(sp, "str literal", suf);
6350 _ => self.fatal("expected string literal")