1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 pub use self::PathParsingMode
::*;
15 use ast
::{RegionTyParamBound, TraitTyParamBound, TraitBoundModifier}
;
16 use ast
::{Public, Unsafety}
;
17 use ast
::{Mod, BiAdd, Arg, Arm, Attribute, BindByRef, BindByValue}
;
18 use ast
::{BiBitAnd, BiBitOr, BiBitXor, BiRem, BiLt, BiGt, Block}
;
19 use ast
::{BlockCheckMode, CaptureByRef, CaptureByValue, CaptureClause}
;
20 use ast
::{Constness, ConstImplItem, ConstTraitItem, Crate, CrateConfig}
;
21 use ast
::{Decl, DeclItem, DeclLocal, DefaultBlock, DefaultReturn}
;
22 use ast
::{UnDeref, BiDiv, EMPTY_CTXT, EnumDef, ExplicitSelf}
;
23 use ast
::{Expr, Expr_, ExprAddrOf, ExprMatch, ExprAgain}
;
24 use ast
::{ExprAssign, ExprAssignOp, ExprBinary, ExprBlock, ExprBox}
;
25 use ast
::{ExprBreak, ExprCall, ExprCast}
;
26 use ast
::{ExprField, ExprTupField, ExprClosure, ExprIf, ExprIfLet, ExprIndex}
;
27 use ast
::{ExprLit, ExprLoop, ExprMac, ExprRange}
;
28 use ast
::{ExprMethodCall, ExprParen, ExprPath}
;
29 use ast
::{ExprRepeat, ExprRet, ExprStruct, ExprTup, ExprUnary}
;
30 use ast
::{ExprVec, ExprWhile, ExprWhileLet, ExprForLoop, Field, FnDecl}
;
31 use ast
::{ForeignItem, ForeignItemStatic, ForeignItemFn, ForeignMod, FunctionRetTy}
;
32 use ast
::{Ident, Inherited, ImplItem, Item, Item_, ItemStatic}
;
33 use ast
::{ItemEnum, ItemFn, ItemForeignMod, ItemImpl, ItemConst}
;
34 use ast
::{ItemMac, ItemMod, ItemStruct, ItemTrait, ItemTy, ItemDefaultImpl}
;
35 use ast
::{ItemExternCrate, ItemUse}
;
36 use ast
::{LifetimeDef, Lit, Lit_}
;
37 use ast
::{LitBool, LitChar, LitByte, LitBinary}
;
38 use ast
::{LitStr, LitInt, Local, LocalLet}
;
39 use ast
::{MacStmtWithBraces, MacStmtWithSemicolon, MacStmtWithoutBraces}
;
40 use ast
::{MutImmutable, MutMutable, Mac_, MacInvocTT, MatchSource}
;
41 use ast
::{MutTy, BiMul, Mutability}
;
42 use ast
::{MethodImplItem, NamedField, UnNeg, NoReturn, UnNot}
;
43 use ast
::{Pat, PatBox, PatEnum, PatIdent, PatLit, PatQPath, PatMac, PatRange}
;
44 use ast
::{PatRegion, PatStruct, PatTup, PatVec, PatWild, PatWildMulti}
;
45 use ast
::PatWildSingle
;
46 use ast
::{PolyTraitRef, QSelf}
;
47 use ast
::{Return, BiShl, BiShr, Stmt, StmtDecl}
;
48 use ast
::{StmtExpr, StmtSemi, StmtMac, StructDef, StructField}
;
49 use ast
::{StructVariantKind, BiSub, StrStyle}
;
50 use ast
::{SelfExplicit, SelfRegion, SelfStatic, SelfValue}
;
51 use ast
::{Delimited, SequenceRepetition, TokenTree, TraitItem, TraitRef}
;
52 use ast
::{TtDelimited, TtSequence, TtToken}
;
53 use ast
::{TupleVariantKind, Ty, Ty_, TypeBinding}
;
54 use ast
::{TyFixedLengthVec, TyBareFn, TyTypeof, TyInfer}
;
55 use ast
::{TyParam, TyParamBound, TyParen, TyPath, TyPolyTraitRef, TyPtr}
;
56 use ast
::{TyRptr, TyTup, TyU32, TyVec, UnUniq}
;
57 use ast
::{TypeImplItem, TypeTraitItem}
;
58 use ast
::{UnnamedField, UnsafeBlock}
;
59 use ast
::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple}
;
60 use ast
::{Visibility, WhereClause}
;
62 use ast_util
::{self, AS_PREC, ident_to_path, operator_prec}
;
63 use codemap
::{self, Span, BytePos, Spanned, spanned, mk_sp}
;
65 use ext
::tt
::macro_parser
;
67 use parse
::attr
::ParserAttr
;
69 use parse
::common
::{SeqSep, seq_sep_none, seq_sep_trailing_allowed}
;
70 use parse
::lexer
::{Reader, TokenAndSpan}
;
71 use parse
::obsolete
::{ParserObsoleteMethods, ObsoleteSyntax}
;
72 use parse
::token
::{self, MatchNt, SubstNt, SpecialVarNt, InternedString}
;
73 use parse
::token
::{keywords, special_idents, SpecialMacroVar}
;
74 use parse
::{new_sub_parser_from_file, ParseSess}
;
77 use owned_slice
::OwnedSlice
;
79 use diagnostic
::FatalError
;
81 use std
::collections
::HashSet
;
82 use std
::io
::prelude
::*;
84 use std
::path
::{Path, PathBuf}
;
89 flags Restrictions
: u8 {
90 const RESTRICTION_STMT_EXPR
= 1 << 0,
91 const RESTRICTION_NO_STRUCT_LITERAL
= 1 << 1,
95 type ItemInfo
= (Ident
, Item_
, Option
<Vec
<Attribute
> >);
97 /// How to parse a path. There are four different kinds of paths, all of which
98 /// are parsed somewhat differently.
99 #[derive(Copy, Clone, PartialEq)]
100 pub enum PathParsingMode
{
101 /// A path with no type parameters; e.g. `foo::bar::Baz`
103 /// A path with a lifetime and type parameters, with no double colons
104 /// before the type parameters; e.g. `foo::bar<'a>::Baz<T>`
105 LifetimeAndTypesWithoutColons
,
106 /// A path with a lifetime and type parameters with double colons before
107 /// the type parameters; e.g. `foo::bar::<'a>::Baz::<T>`
108 LifetimeAndTypesWithColons
,
111 /// How to parse a bound, whether to allow bound modifiers such as `?`.
112 #[derive(Copy, Clone, PartialEq)]
113 pub enum BoundParsingMode
{
118 /// Possibly accept an `token::Interpolated` expression (a pre-parsed expression
119 /// dropped into the token stream, which happens while parsing the result of
120 /// macro expansion). Placement of these is not as complex as I feared it would
121 /// be. The important thing is to make sure that lookahead doesn't balk at
122 /// `token::Interpolated` tokens.
123 macro_rules
! maybe_whole_expr
{
126 let found
= match $p
.token
{
127 token
::Interpolated(token
::NtExpr(ref e
)) => {
130 token
::Interpolated(token
::NtPath(_
)) => {
131 // FIXME: The following avoids an issue with lexical borrowck scopes,
132 // but the clone is unfortunate.
133 let pt
= match $p
.token
{
134 token
::Interpolated(token
::NtPath(ref pt
)) => (**pt
).clone(),
138 Some($p
.mk_expr(span
.lo
, span
.hi
, ExprPath(None
, pt
)))
140 token
::Interpolated(token
::NtBlock(_
)) => {
141 // FIXME: The following avoids an issue with lexical borrowck scopes,
142 // but the clone is unfortunate.
143 let b
= match $p
.token
{
144 token
::Interpolated(token
::NtBlock(ref b
)) => (*b
).clone(),
148 Some($p
.mk_expr(span
.lo
, span
.hi
, ExprBlock(b
)))
163 /// As maybe_whole_expr, but for things other than expressions
164 macro_rules
! maybe_whole
{
165 ($p
:expr
, $constructor
:ident
) => (
167 let found
= match ($p
).token
{
168 token
::Interpolated(token
::$
constructor(_
)) => {
169 Some(try
!(($p
).bump_and_get()))
173 if let Some(token
::Interpolated(token
::$
constructor(x
))) = found
{
174 return Ok(x
.clone());
178 (no_clone $p
:expr
, $constructor
:ident
) => (
180 let found
= match ($p
).token
{
181 token
::Interpolated(token
::$
constructor(_
)) => {
182 Some(try
!(($p
).bump_and_get()))
186 if let Some(token
::Interpolated(token
::$
constructor(x
))) = found
{
191 (deref $p
:expr
, $constructor
:ident
) => (
193 let found
= match ($p
).token
{
194 token
::Interpolated(token
::$
constructor(_
)) => {
195 Some(try
!(($p
).bump_and_get()))
199 if let Some(token
::Interpolated(token
::$
constructor(x
))) = found
{
200 return Ok((*x
).clone());
204 (Some deref $p
:expr
, $constructor
:ident
) => (
206 let found
= match ($p
).token
{
207 token
::Interpolated(token
::$
constructor(_
)) => {
208 Some(try
!(($p
).bump_and_get()))
212 if let Some(token
::Interpolated(token
::$
constructor(x
))) = found
{
213 return Ok(Some((*x
).clone()));
217 (pair_empty $p
:expr
, $constructor
:ident
) => (
219 let found
= match ($p
).token
{
220 token
::Interpolated(token
::$
constructor(_
)) => {
221 Some(try
!(($p
).bump_and_get()))
225 if let Some(token
::Interpolated(token
::$
constructor(x
))) = found
{
226 return Ok((Vec
::new(), x
));
233 fn maybe_append(mut lhs
: Vec
<Attribute
>, rhs
: Option
<Vec
<Attribute
>>)
235 if let Some(ref attrs
) = rhs
{
236 lhs
.extend(attrs
.iter().cloned())
241 /* ident is handled by common.rs */
243 pub struct Parser
<'a
> {
244 pub sess
: &'a ParseSess
,
245 /// the current token:
246 pub token
: token
::Token
,
247 /// the span of the current token:
249 /// the span of the prior token:
251 pub cfg
: CrateConfig
,
252 /// the previous token or None (only stashed sometimes).
253 pub last_token
: Option
<Box
<token
::Token
>>,
254 pub buffer
: [TokenAndSpan
; 4],
255 pub buffer_start
: isize,
256 pub buffer_end
: isize,
257 pub tokens_consumed
: usize,
258 pub restrictions
: Restrictions
,
259 pub quote_depth
: usize, // not (yet) related to the quasiquoter
260 pub reader
: Box
<Reader
+'a
>,
261 pub interner
: Rc
<token
::IdentInterner
>,
262 /// The set of seen errors about obsolete syntax. Used to suppress
263 /// extra detail when the same error is seen twice
264 pub obsolete_set
: HashSet
<ObsoleteSyntax
>,
265 /// Used to determine the path to externally loaded source files
266 pub mod_path_stack
: Vec
<InternedString
>,
267 /// Stack of spans of open delimiters. Used for error message.
268 pub open_braces
: Vec
<Span
>,
269 /// Flag if this parser "owns" the directory that it is currently parsing
270 /// in. This will affect how nested files are looked up.
271 pub owns_directory
: bool
,
272 /// Name of the root module this parser originated from. If `None`, then the
273 /// name is not known. This does not change while the parser is descending
274 /// into modules, and sub-parsers have new values for this name.
275 pub root_module_name
: Option
<String
>,
276 pub expected_tokens
: Vec
<TokenType
>,
279 #[derive(PartialEq, Eq, Clone)]
282 Keyword(keywords
::Keyword
),
287 fn to_string(&self) -> String
{
289 TokenType
::Token(ref t
) => format
!("`{}`", Parser
::token_to_string(t
)),
290 TokenType
::Operator
=> "an operator".to_string(),
291 TokenType
::Keyword(kw
) => format
!("`{}`", token
::get_name(kw
.to_name())),
296 fn is_plain_ident_or_underscore(t
: &token
::Token
) -> bool
{
297 t
.is_plain_ident() || *t
== token
::Underscore
300 impl<'a
> Parser
<'a
> {
301 pub fn new(sess
: &'a ParseSess
,
302 cfg
: ast
::CrateConfig
,
303 mut rdr
: Box
<Reader
+'a
>)
306 let tok0
= rdr
.real_token();
308 let placeholder
= TokenAndSpan
{
309 tok
: token
::Underscore
,
315 interner
: token
::get_ident_interner(),
331 restrictions
: Restrictions
::empty(),
333 obsolete_set
: HashSet
::new(),
334 mod_path_stack
: Vec
::new(),
335 open_braces
: Vec
::new(),
336 owns_directory
: true,
337 root_module_name
: None
,
338 expected_tokens
: Vec
::new(),
342 // Panicing fns (for now!)
343 // This is so that the quote_*!() syntax extensions
344 pub fn parse_expr(&mut self) -> P
<Expr
> {
345 panictry
!(self.parse_expr_nopanic())
348 pub fn parse_item(&mut self) -> Option
<P
<Item
>> {
349 panictry
!(self.parse_item_nopanic())
352 pub fn parse_pat(&mut self) -> P
<Pat
> {
353 panictry
!(self.parse_pat_nopanic())
356 pub fn parse_arm(&mut self) -> Arm
{
357 panictry
!(self.parse_arm_nopanic())
360 pub fn parse_ty(&mut self) -> P
<Ty
> {
361 panictry
!(self.parse_ty_nopanic())
364 pub fn parse_stmt(&mut self) -> Option
<P
<Stmt
>> {
365 panictry
!(self.parse_stmt_nopanic())
368 /// Convert a token to a string using self's reader
369 pub fn token_to_string(token
: &token
::Token
) -> String
{
370 pprust
::token_to_string(token
)
373 /// Convert the current token to a string using self's reader
374 pub fn this_token_to_string(&self) -> String
{
375 Parser
::token_to_string(&self.token
)
378 pub fn unexpected_last(&self, t
: &token
::Token
) -> FatalError
{
379 let token_str
= Parser
::token_to_string(t
);
380 let last_span
= self.last_span
;
381 self.span_fatal(last_span
, &format
!("unexpected token: `{}`",
385 pub fn unexpected(&mut self) -> FatalError
{
386 match self.expect_one_of(&[], &[]) {
388 Ok(_
) => unreachable
!()
392 /// Expect and consume the token t. Signal an error if
393 /// the next token is not t.
394 pub fn expect(&mut self, t
: &token
::Token
) -> PResult
<()> {
395 if self.expected_tokens
.is_empty() {
396 if self.token
== *t
{
399 let token_str
= Parser
::token_to_string(t
);
400 let this_token_str
= self.this_token_to_string();
401 Err(self.fatal(&format
!("expected `{}`, found `{}`",
406 self.expect_one_of(slice
::ref_slice(t
), &[])
410 /// Expect next token to be edible or inedible token. If edible,
411 /// then consume it; if inedible, then return without consuming
412 /// anything. Signal a fatal error if next token is unexpected.
413 pub fn expect_one_of(&mut self,
414 edible
: &[token
::Token
],
415 inedible
: &[token
::Token
]) -> PResult
<()>{
416 fn tokens_to_string(tokens
: &[TokenType
]) -> String
{
417 let mut i
= tokens
.iter();
418 // This might be a sign we need a connect method on Iterator.
420 .map_or("".to_string(), |t
| t
.to_string());
421 i
.enumerate().fold(b
, |mut b
, (i
, ref a
)| {
422 if tokens
.len() > 2 && i
== tokens
.len() - 2 {
424 } else if tokens
.len() == 2 && i
== tokens
.len() - 2 {
429 b
.push_str(&*a
.to_string());
433 if edible
.contains(&self.token
) {
435 } else if inedible
.contains(&self.token
) {
436 // leave it in the input
439 let mut expected
= edible
.iter()
440 .map(|x
| TokenType
::Token(x
.clone()))
441 .chain(inedible
.iter().map(|x
| TokenType
::Token(x
.clone())))
442 .chain(self.expected_tokens
.iter().cloned())
443 .collect
::<Vec
<_
>>();
444 expected
.sort_by(|a
, b
| a
.to_string().cmp(&b
.to_string()));
446 let expect
= tokens_to_string(&expected
[..]);
447 let actual
= self.this_token_to_string();
449 &(if expected
.len() > 1 {
450 (format
!("expected one of {}, found `{}`",
453 } else if expected
.is_empty() {
454 (format
!("unexpected token: `{}`",
457 (format
!("expected {}, found `{}`",
465 /// Check for erroneous `ident { }`; if matches, signal error and
466 /// recover (without consuming any expected input token). Returns
467 /// true if and only if input was consumed for recovery.
468 pub fn check_for_erroneous_unit_struct_expecting(&mut self,
469 expected
: &[token
::Token
])
471 if self.token
== token
::OpenDelim(token
::Brace
)
472 && expected
.iter().all(|t
| *t
!= token
::OpenDelim(token
::Brace
))
473 && self.look_ahead(1, |t
| *t
== token
::CloseDelim(token
::Brace
)) {
474 // matched; signal non-fatal error and recover.
475 let span
= self.span
;
477 "unit-like struct construction is written with no trailing `{ }`");
478 try
!(self.eat(&token
::OpenDelim(token
::Brace
)));
479 try
!(self.eat(&token
::CloseDelim(token
::Brace
)));
486 /// Commit to parsing a complete expression `e` expected to be
487 /// followed by some token from the set edible + inedible. Recover
488 /// from anticipated input errors, discarding erroneous characters.
489 pub fn commit_expr(&mut self, e
: &Expr
, edible
: &[token
::Token
],
490 inedible
: &[token
::Token
]) -> PResult
<()> {
491 debug
!("commit_expr {:?}", e
);
492 if let ExprPath(..) = e
.node
{
493 // might be unit-struct construction; check for recoverableinput error.
494 let expected
= edible
.iter()
496 .chain(inedible
.iter().cloned())
497 .collect
::<Vec
<_
>>();
498 try
!(self.check_for_erroneous_unit_struct_expecting(&expected
[..]));
500 self.expect_one_of(edible
, inedible
)
503 pub fn commit_expr_expecting(&mut self, e
: &Expr
, edible
: token
::Token
) -> PResult
<()> {
504 self.commit_expr(e
, &[edible
], &[])
507 /// Commit to parsing a complete statement `s`, which expects to be
508 /// followed by some token from the set edible + inedible. Check
509 /// for recoverable input errors, discarding erroneous characters.
510 pub fn commit_stmt(&mut self, edible
: &[token
::Token
],
511 inedible
: &[token
::Token
]) -> PResult
<()> {
514 .map_or(false, |t
| t
.is_ident() || t
.is_path()) {
515 let expected
= edible
.iter()
517 .chain(inedible
.iter().cloned())
518 .collect
::<Vec
<_
>>();
519 try
!(self.check_for_erroneous_unit_struct_expecting(&expected
));
521 self.expect_one_of(edible
, inedible
)
524 pub fn commit_stmt_expecting(&mut self, edible
: token
::Token
) -> PResult
<()> {
525 self.commit_stmt(&[edible
], &[])
528 pub fn parse_ident(&mut self) -> PResult
<ast
::Ident
> {
529 self.check_strict_keywords();
530 try
!(self.check_reserved_keywords());
532 token
::Ident(i
, _
) => {
536 token
::Interpolated(token
::NtIdent(..)) => {
537 self.bug("ident interpolation not converted to real token");
540 let token_str
= self.this_token_to_string();
541 Err(self.fatal(&format
!("expected ident, found `{}`",
547 pub fn parse_ident_or_self_type(&mut self) -> PResult
<ast
::Ident
> {
548 if self.is_self_type_ident() {
549 self.expect_self_type_ident()
555 pub fn parse_path_list_item(&mut self) -> PResult
<ast
::PathListItem
> {
556 let lo
= self.span
.lo
;
557 let node
= if try
!(self.eat_keyword(keywords
::SelfValue
)) {
558 ast
::PathListMod { id: ast::DUMMY_NODE_ID }
560 let ident
= try
!(self.parse_ident());
561 ast
::PathListIdent { name: ident, id: ast::DUMMY_NODE_ID }
563 let hi
= self.last_span
.hi
;
564 Ok(spanned(lo
, hi
, node
))
567 /// Check if the next token is `tok`, and return `true` if so.
569 /// This method is will automatically add `tok` to `expected_tokens` if `tok` is not
571 pub fn check(&mut self, tok
: &token
::Token
) -> bool
{
572 let is_present
= self.token
== *tok
;
573 if !is_present { self.expected_tokens.push(TokenType::Token(tok.clone())); }
577 /// Consume token 'tok' if it exists. Returns true if the given
578 /// token was present, false otherwise.
579 pub fn eat(&mut self, tok
: &token
::Token
) -> PResult
<bool
> {
580 let is_present
= self.check(tok
);
581 if is_present { try!(self.bump())}
585 pub fn check_keyword(&mut self, kw
: keywords
::Keyword
) -> bool
{
586 self.expected_tokens
.push(TokenType
::Keyword(kw
));
587 self.token
.is_keyword(kw
)
590 /// If the next token is the given keyword, eat it and return
591 /// true. Otherwise, return false.
592 pub fn eat_keyword(&mut self, kw
: keywords
::Keyword
) -> PResult
<bool
> {
593 if self.check_keyword(kw
) {
601 pub fn eat_keyword_noexpect(&mut self, kw
: keywords
::Keyword
) -> PResult
<bool
> {
602 if self.token
.is_keyword(kw
) {
610 /// If the given word is not a keyword, signal an error.
611 /// If the next token is not the given word, signal an error.
612 /// Otherwise, eat it.
613 pub fn expect_keyword(&mut self, kw
: keywords
::Keyword
) -> PResult
<()> {
614 if !try
!(self.eat_keyword(kw
) ){
615 self.expect_one_of(&[], &[])
621 /// Signal an error if the given string is a strict keyword
622 pub fn check_strict_keywords(&mut self) {
623 if self.token
.is_strict_keyword() {
624 let token_str
= self.this_token_to_string();
625 let span
= self.span
;
627 &format
!("expected identifier, found keyword `{}`",
632 /// Signal an error if the current token is a reserved keyword
633 pub fn check_reserved_keywords(&mut self) -> PResult
<()>{
634 if self.token
.is_reserved_keyword() {
635 let token_str
= self.this_token_to_string();
636 Err(self.fatal(&format
!("`{}` is a reserved keyword",
643 /// Expect and consume an `&`. If `&&` is seen, replace it with a single
644 /// `&` and continue. If an `&` is not seen, signal an error.
645 fn expect_and(&mut self) -> PResult
<()> {
646 self.expected_tokens
.push(TokenType
::Token(token
::BinOp(token
::And
)));
648 token
::BinOp(token
::And
) => self.bump(),
650 let span
= self.span
;
651 let lo
= span
.lo
+ BytePos(1);
652 Ok(self.replace_token(token
::BinOp(token
::And
), lo
, span
.hi
))
654 _
=> self.expect_one_of(&[], &[])
658 pub fn expect_no_suffix(&self, sp
: Span
, kind
: &str, suffix
: Option
<ast
::Name
>) {
660 None
=> {/* everything ok */}
662 let text
= suf
.as_str();
664 self.span_bug(sp
, "found empty literal suffix in Some")
666 self.span_err(sp
, &*format
!("{} with a suffix is illegal", kind
));
672 /// Attempt to consume a `<`. If `<<` is seen, replace it with a single
673 /// `<` and continue. If a `<` is not seen, return false.
675 /// This is meant to be used when parsing generics on a path to get the
677 fn eat_lt(&mut self) -> PResult
<bool
> {
678 self.expected_tokens
.push(TokenType
::Token(token
::Lt
));
680 token
::Lt
=> { try!(self.bump()); Ok(true)}
681 token
::BinOp(token
::Shl
) => {
682 let span
= self.span
;
683 let lo
= span
.lo
+ BytePos(1);
684 self.replace_token(token
::Lt
, lo
, span
.hi
);
691 fn expect_lt(&mut self) -> PResult
<()> {
692 if !try
!(self.eat_lt()) {
693 self.expect_one_of(&[], &[])
699 /// Expect and consume a GT. if a >> is seen, replace it
700 /// with a single > and continue. If a GT is not seen,
702 pub fn expect_gt(&mut self) -> PResult
<()> {
703 self.expected_tokens
.push(TokenType
::Token(token
::Gt
));
705 token
::Gt
=> self.bump(),
706 token
::BinOp(token
::Shr
) => {
707 let span
= self.span
;
708 let lo
= span
.lo
+ BytePos(1);
709 Ok(self.replace_token(token
::Gt
, lo
, span
.hi
))
711 token
::BinOpEq(token
::Shr
) => {
712 let span
= self.span
;
713 let lo
= span
.lo
+ BytePos(1);
714 Ok(self.replace_token(token
::Ge
, lo
, span
.hi
))
717 let span
= self.span
;
718 let lo
= span
.lo
+ BytePos(1);
719 Ok(self.replace_token(token
::Eq
, lo
, span
.hi
))
722 let gt_str
= Parser
::token_to_string(&token
::Gt
);
723 let this_token_str
= self.this_token_to_string();
724 Err(self.fatal(&format
!("expected `{}`, found `{}`",
731 pub fn parse_seq_to_before_gt_or_return
<T
, F
>(&mut self,
732 sep
: Option
<token
::Token
>,
734 -> PResult
<(OwnedSlice
<T
>, bool
)> where
735 F
: FnMut(&mut Parser
) -> PResult
<Option
<T
>>,
737 let mut v
= Vec
::new();
738 // This loop works by alternating back and forth between parsing types
739 // and commas. For example, given a string `A, B,>`, the parser would
740 // first parse `A`, then a comma, then `B`, then a comma. After that it
741 // would encounter a `>` and stop. This lets the parser handle trailing
742 // commas in generic parameters, because it can stop either after
743 // parsing a type or after parsing a comma.
745 if self.check(&token
::Gt
)
746 || self.token
== token
::BinOp(token
::Shr
)
747 || self.token
== token
::Ge
748 || self.token
== token
::BinOpEq(token
::Shr
) {
753 match try
!(f(self)) {
754 Some(result
) => v
.push(result
),
755 None
=> return Ok((OwnedSlice
::from_vec(v
), true))
758 if let Some(t
) = sep
.as_ref() {
759 try
!(self.expect(t
));
764 return Ok((OwnedSlice
::from_vec(v
), false));
767 /// Parse a sequence bracketed by '<' and '>', stopping
769 pub fn parse_seq_to_before_gt
<T
, F
>(&mut self,
770 sep
: Option
<token
::Token
>,
772 -> PResult
<OwnedSlice
<T
>> where
773 F
: FnMut(&mut Parser
) -> PResult
<T
>,
775 let (result
, returned
) = try
!(self.parse_seq_to_before_gt_or_return(sep
,
776 |p
| Ok(Some(try
!(f(p
))))));
781 pub fn parse_seq_to_gt
<T
, F
>(&mut self,
782 sep
: Option
<token
::Token
>,
784 -> PResult
<OwnedSlice
<T
>> where
785 F
: FnMut(&mut Parser
) -> PResult
<T
>,
787 let v
= try
!(self.parse_seq_to_before_gt(sep
, f
));
788 try
!(self.expect_gt());
792 pub fn parse_seq_to_gt_or_return
<T
, F
>(&mut self,
793 sep
: Option
<token
::Token
>,
795 -> PResult
<(OwnedSlice
<T
>, bool
)> where
796 F
: FnMut(&mut Parser
) -> PResult
<Option
<T
>>,
798 let (v
, returned
) = try
!(self.parse_seq_to_before_gt_or_return(sep
, f
));
800 try
!(self.expect_gt());
802 return Ok((v
, returned
));
805 /// Parse a sequence, including the closing delimiter. The function
806 /// f must consume tokens until reaching the next separator or
808 pub fn parse_seq_to_end
<T
, F
>(&mut self,
812 -> PResult
<Vec
<T
>> where
813 F
: FnMut(&mut Parser
) -> PResult
<T
>,
815 let val
= try
!(self.parse_seq_to_before_end(ket
, sep
, f
));
820 /// Parse a sequence, not including the closing delimiter. The function
821 /// f must consume tokens until reaching the next separator or
823 pub fn parse_seq_to_before_end
<T
, F
>(&mut self,
827 -> PResult
<Vec
<T
>> where
828 F
: FnMut(&mut Parser
) -> PResult
<T
>,
830 let mut first
: bool
= true;
832 while self.token
!= *ket
{
835 if first { first = false; }
836 else { try!(self.expect(t)); }
840 if sep
.trailing_sep_allowed
&& self.check(ket
) { break; }
841 v
.push(try
!(f(self)));
846 /// Parse a sequence, including the closing delimiter. The function
847 /// f must consume tokens until reaching the next separator or
849 pub fn parse_unspanned_seq
<T
, F
>(&mut self,
854 -> PResult
<Vec
<T
>> where
855 F
: FnMut(&mut Parser
) -> PResult
<T
>,
857 try
!(self.expect(bra
));
858 let result
= try
!(self.parse_seq_to_before_end(ket
, sep
, f
));
863 /// Parse a sequence parameter of enum variant. For consistency purposes,
864 /// these should not be empty.
865 pub fn parse_enum_variant_seq
<T
, F
>(&mut self,
870 -> PResult
<Vec
<T
>> where
871 F
: FnMut(&mut Parser
) -> PResult
<T
>,
873 let result
= try
!(self.parse_unspanned_seq(bra
, ket
, sep
, f
));
874 if result
.is_empty() {
875 let last_span
= self.last_span
;
876 self.span_err(last_span
,
877 "nullary enum variants are written with no trailing `( )`");
882 // NB: Do not use this function unless you actually plan to place the
883 // spanned list in the AST.
884 pub fn parse_seq
<T
, F
>(&mut self,
889 -> PResult
<Spanned
<Vec
<T
>>> where
890 F
: FnMut(&mut Parser
) -> PResult
<T
>,
892 let lo
= self.span
.lo
;
893 try
!(self.expect(bra
));
894 let result
= try
!(self.parse_seq_to_before_end(ket
, sep
, f
));
895 let hi
= self.span
.hi
;
897 Ok(spanned(lo
, hi
, result
))
900 /// Advance the parser by one token
901 pub fn bump(&mut self) -> PResult
<()> {
902 self.last_span
= self.span
;
903 // Stash token for error recovery (sometimes; clone is not necessarily cheap).
904 self.last_token
= if self.token
.is_ident() ||
905 self.token
.is_path() ||
906 self.token
== token
::Comma
{
907 Some(Box
::new(self.token
.clone()))
911 let next
= if self.buffer_start
== self.buffer_end
{
912 self.reader
.real_token()
914 // Avoid token copies with `replace`.
915 let buffer_start
= self.buffer_start
as usize;
916 let next_index
= (buffer_start
+ 1) & 3;
917 self.buffer_start
= next_index
as isize;
919 let placeholder
= TokenAndSpan
{
920 tok
: token
::Underscore
,
923 mem
::replace(&mut self.buffer
[buffer_start
], placeholder
)
926 self.token
= next
.tok
;
927 self.tokens_consumed
+= 1;
928 self.expected_tokens
.clear();
929 // check after each token
930 self.check_unknown_macro_variable()
933 /// Advance the parser by one token and return the bumped token.
934 pub fn bump_and_get(&mut self) -> PResult
<token
::Token
> {
935 let old_token
= mem
::replace(&mut self.token
, token
::Underscore
);
940 /// EFFECT: replace the current token and span with the given one
941 pub fn replace_token(&mut self,
945 self.last_span
= mk_sp(self.span
.lo
, lo
);
947 self.span
= mk_sp(lo
, hi
);
949 pub fn buffer_length(&mut self) -> isize {
950 if self.buffer_start
<= self.buffer_end
{
951 return self.buffer_end
- self.buffer_start
;
953 return (4 - self.buffer_start
) + self.buffer_end
;
955 pub fn look_ahead
<R
, F
>(&mut self, distance
: usize, f
: F
) -> R
where
956 F
: FnOnce(&token
::Token
) -> R
,
958 let dist
= distance
as isize;
959 while self.buffer_length() < dist
{
960 self.buffer
[self.buffer_end
as usize] = self.reader
.real_token();
961 self.buffer_end
= (self.buffer_end
+ 1) & 3;
963 f(&self.buffer
[((self.buffer_start
+ dist
- 1) & 3) as usize].tok
)
965 pub fn fatal(&self, m
: &str) -> diagnostic
::FatalError
{
966 self.sess
.span_diagnostic
.span_fatal(self.span
, m
)
968 pub fn span_fatal(&self, sp
: Span
, m
: &str) -> diagnostic
::FatalError
{
969 self.sess
.span_diagnostic
.span_fatal(sp
, m
)
971 pub fn span_fatal_help(&self, sp
: Span
, m
: &str, help
: &str) -> diagnostic
::FatalError
{
972 self.span_err(sp
, m
);
973 self.fileline_help(sp
, help
);
974 diagnostic
::FatalError
976 pub fn span_note(&self, sp
: Span
, m
: &str) {
977 self.sess
.span_diagnostic
.span_note(sp
, m
)
979 pub fn span_help(&self, sp
: Span
, m
: &str) {
980 self.sess
.span_diagnostic
.span_help(sp
, m
)
982 pub fn span_suggestion(&self, sp
: Span
, m
: &str, n
: String
) {
983 self.sess
.span_diagnostic
.span_suggestion(sp
, m
, n
)
985 pub fn fileline_help(&self, sp
: Span
, m
: &str) {
986 self.sess
.span_diagnostic
.fileline_help(sp
, m
)
988 pub fn bug(&self, m
: &str) -> ! {
989 self.sess
.span_diagnostic
.span_bug(self.span
, m
)
991 pub fn warn(&self, m
: &str) {
992 self.sess
.span_diagnostic
.span_warn(self.span
, m
)
994 pub fn span_warn(&self, sp
: Span
, m
: &str) {
995 self.sess
.span_diagnostic
.span_warn(sp
, m
)
997 pub fn span_err(&self, sp
: Span
, m
: &str) {
998 self.sess
.span_diagnostic
.span_err(sp
, m
)
1000 pub fn span_bug(&self, sp
: Span
, m
: &str) -> ! {
1001 self.sess
.span_diagnostic
.span_bug(sp
, m
)
1003 pub fn abort_if_errors(&self) {
1004 self.sess
.span_diagnostic
.handler().abort_if_errors();
1007 pub fn id_to_interned_str(&mut self, id
: Ident
) -> InternedString
{
1008 token
::get_ident(id
)
1011 /// Is the current token one of the keywords that signals a bare function
1013 pub fn token_is_bare_fn_keyword(&mut self) -> bool
{
1014 self.check_keyword(keywords
::Fn
) ||
1015 self.check_keyword(keywords
::Unsafe
) ||
1016 self.check_keyword(keywords
::Extern
)
1019 pub fn get_lifetime(&mut self) -> ast
::Ident
{
1021 token
::Lifetime(ref ident
) => *ident
,
1022 _
=> self.bug("not a lifetime"),
1026 pub fn parse_for_in_type(&mut self) -> PResult
<Ty_
> {
1028 Parses whatever can come after a `for` keyword in a type.
1029 The `for` has already been consumed.
1033 - for <'lt> |S| -> T
1037 - for <'lt> [unsafe] [extern "ABI"] fn (S) -> T
1038 - for <'lt> path::foo(a, b)
1043 let lo
= self.span
.lo
;
1045 let lifetime_defs
= try
!(self.parse_late_bound_lifetime_defs());
1047 // examine next token to decide to do
1048 if self.token_is_bare_fn_keyword() {
1049 self.parse_ty_bare_fn(lifetime_defs
)
1051 let hi
= self.span
.hi
;
1052 let trait_ref
= try
!(self.parse_trait_ref());
1053 let poly_trait_ref
= ast
::PolyTraitRef
{ bound_lifetimes
: lifetime_defs
,
1054 trait_ref
: trait_ref
,
1055 span
: mk_sp(lo
, hi
)};
1056 let other_bounds
= if try
!(self.eat(&token
::BinOp(token
::Plus
)) ){
1057 try
!(self.parse_ty_param_bounds(BoundParsingMode
::Bare
))
1062 Some(TraitTyParamBound(poly_trait_ref
, TraitBoundModifier
::None
)).into_iter()
1063 .chain(other_bounds
.into_vec())
1065 Ok(ast
::TyPolyTraitRef(all_bounds
))
1069 pub fn parse_ty_path(&mut self) -> PResult
<Ty_
> {
1070 Ok(TyPath(None
, try
!(self.parse_path(LifetimeAndTypesWithoutColons
))))
1073 /// parse a TyBareFn type:
1074 pub fn parse_ty_bare_fn(&mut self, lifetime_defs
: Vec
<ast
::LifetimeDef
>) -> PResult
<Ty_
> {
1077 [unsafe] [extern "ABI"] fn <'lt> (S) -> T
1078 ^~~~^ ^~~~^ ^~~~^ ^~^ ^
1081 | | | Argument types
1087 let unsafety
= try
!(self.parse_unsafety());
1088 let abi
= if try
!(self.eat_keyword(keywords
::Extern
) ){
1089 try
!(self.parse_opt_abi()).unwrap_or(abi
::C
)
1094 try
!(self.expect_keyword(keywords
::Fn
));
1095 let (inputs
, variadic
) = try
!(self.parse_fn_args(false, true));
1096 let ret_ty
= try
!(self.parse_ret_ty());
1097 let decl
= P(FnDecl
{
1102 Ok(TyBareFn(P(BareFnTy
{
1105 lifetimes
: lifetime_defs
,
1110 /// Parses an obsolete closure kind (`&:`, `&mut:`, or `:`).
1111 pub fn parse_obsolete_closure_kind(&mut self) -> PResult
<()> {
1112 let lo
= self.span
.lo
;
1114 self.check(&token
::BinOp(token
::And
)) &&
1115 self.look_ahead(1, |t
| t
.is_keyword(keywords
::Mut
)) &&
1116 self.look_ahead(2, |t
| *t
== token
::Colon
)
1122 self.token
== token
::BinOp(token
::And
) &&
1123 self.look_ahead(1, |t
| *t
== token
::Colon
)
1128 try
!(self.eat(&token
::Colon
))
1135 let span
= mk_sp(lo
, self.span
.hi
);
1136 self.obsolete(span
, ObsoleteSyntax
::ClosureKind
);
1140 pub fn parse_unsafety(&mut self) -> PResult
<Unsafety
> {
1141 if try
!(self.eat_keyword(keywords
::Unsafe
)) {
1142 return Ok(Unsafety
::Unsafe
);
1144 return Ok(Unsafety
::Normal
);
1148 /// Parse the items in a trait declaration
1149 pub fn parse_trait_items(&mut self) -> PResult
<Vec
<P
<TraitItem
>>> {
1150 self.parse_unspanned_seq(
1151 &token
::OpenDelim(token
::Brace
),
1152 &token
::CloseDelim(token
::Brace
),
1154 |p
| -> PResult
<P
<TraitItem
>> {
1155 maybe_whole
!(no_clone p
, NtTraitItem
);
1156 let mut attrs
= p
.parse_outer_attributes();
1159 let (name
, node
) = if try
!(p
.eat_keyword(keywords
::Type
)) {
1160 let TyParam {ident, bounds, default, ..}
= try
!(p
.parse_ty_param());
1161 try
!(p
.expect(&token
::Semi
));
1162 (ident
, TypeTraitItem(bounds
, default))
1163 } else if p
.is_const_item() {
1164 try
!(p
.expect_keyword(keywords
::Const
));
1165 let ident
= try
!(p
.parse_ident());
1166 try
!(p
.expect(&token
::Colon
));
1167 let ty
= try
!(p
.parse_ty_sum());
1168 let default = if p
.check(&token
::Eq
) {
1170 let expr
= try
!(p
.parse_expr_nopanic());
1171 try
!(p
.commit_expr_expecting(&expr
, token
::Semi
));
1174 try
!(p
.expect(&token
::Semi
));
1177 (ident
, ConstTraitItem(ty
, default))
1179 let (constness
, unsafety
, abi
) = try
!(p
.parse_fn_front_matter());
1181 let ident
= try
!(p
.parse_ident());
1182 let mut generics
= try
!(p
.parse_generics());
1184 let (explicit_self
, d
) = try
!(p
.parse_fn_decl_with_self(|p
|{
1185 // This is somewhat dubious; We don't want to allow
1186 // argument names to be left off if there is a
1188 p
.parse_arg_general(false)
1191 generics
.where_clause
= try
!(p
.parse_where_clause());
1192 let sig
= ast
::MethodSig
{
1194 constness
: constness
,
1198 explicit_self
: explicit_self
,
1201 let body
= match p
.token
{
1204 debug
!("parse_trait_methods(): parsing required method");
1207 token
::OpenDelim(token
::Brace
) => {
1208 debug
!("parse_trait_methods(): parsing provided method");
1209 let (inner_attrs
, body
) =
1210 try
!(p
.parse_inner_attrs_and_block());
1211 attrs
.extend(inner_attrs
.iter().cloned());
1216 let token_str
= p
.this_token_to_string();
1217 return Err(p
.fatal(&format
!("expected `;` or `{{`, found `{}`",
1221 (ident
, ast
::MethodTraitItem(sig
, body
))
1225 id
: ast
::DUMMY_NODE_ID
,
1229 span
: mk_sp(lo
, p
.last_span
.hi
),
1234 /// Parse a possibly mutable type
1235 pub fn parse_mt(&mut self) -> PResult
<MutTy
> {
1236 let mutbl
= try
!(self.parse_mutability());
1237 let t
= try
!(self.parse_ty_nopanic());
1238 Ok(MutTy { ty: t, mutbl: mutbl }
)
1241 /// Parse optional return type [ -> TY ] in function decl
1242 pub fn parse_ret_ty(&mut self) -> PResult
<FunctionRetTy
> {
1243 if try
!(self.eat(&token
::RArrow
) ){
1244 if try
!(self.eat(&token
::Not
) ){
1245 Ok(NoReturn(self.span
))
1247 Ok(Return(try
!(self.parse_ty_nopanic())))
1250 let pos
= self.span
.lo
;
1251 Ok(DefaultReturn(mk_sp(pos
, pos
)))
1255 /// Parse a type in a context where `T1+T2` is allowed.
1256 pub fn parse_ty_sum(&mut self) -> PResult
<P
<Ty
>> {
1257 let lo
= self.span
.lo
;
1258 let lhs
= try
!(self.parse_ty_nopanic());
1260 if !try
!(self.eat(&token
::BinOp(token
::Plus
)) ){
1264 let bounds
= try
!(self.parse_ty_param_bounds(BoundParsingMode
::Bare
));
1266 // In type grammar, `+` is treated like a binary operator,
1267 // and hence both L and R side are required.
1268 if bounds
.is_empty() {
1269 let last_span
= self.last_span
;
1270 self.span_err(last_span
,
1271 "at least one type parameter bound \
1272 must be specified");
1275 let sp
= mk_sp(lo
, self.last_span
.hi
);
1276 let sum
= ast
::TyObjectSum(lhs
, bounds
);
1277 Ok(P(Ty {id: ast::DUMMY_NODE_ID, node: sum, span: sp}
))
1281 pub fn parse_ty_nopanic(&mut self) -> PResult
<P
<Ty
>> {
1282 maybe_whole
!(no_clone
self, NtTy
);
1284 let lo
= self.span
.lo
;
1286 let t
= if self.check(&token
::OpenDelim(token
::Paren
)) {
1289 // (t) is a parenthesized ty
1290 // (t,) is the type of a tuple with only one field,
1292 let mut ts
= vec
![];
1293 let mut last_comma
= false;
1294 while self.token
!= token
::CloseDelim(token
::Paren
) {
1295 ts
.push(try
!(self.parse_ty_sum()));
1296 if self.check(&token
::Comma
) {
1305 try
!(self.expect(&token
::CloseDelim(token
::Paren
)));
1306 if ts
.len() == 1 && !last_comma
{
1307 TyParen(ts
.into_iter().nth(0).unwrap())
1311 } else if self.check(&token
::BinOp(token
::Star
)) {
1312 // STAR POINTER (bare pointer?)
1314 TyPtr(try
!(self.parse_ptr()))
1315 } else if self.check(&token
::OpenDelim(token
::Bracket
)) {
1317 try
!(self.expect(&token
::OpenDelim(token
::Bracket
)));
1318 let t
= try
!(self.parse_ty_sum());
1320 // Parse the `; e` in `[ i32; e ]`
1321 // where `e` is a const expression
1322 let t
= match try
!(self.maybe_parse_fixed_length_of_vec()) {
1324 Some(suffix
) => TyFixedLengthVec(t
, suffix
)
1326 try
!(self.expect(&token
::CloseDelim(token
::Bracket
)));
1328 } else if self.check(&token
::BinOp(token
::And
)) ||
1329 self.token
== token
::AndAnd
{
1331 try
!(self.expect_and());
1332 try
!(self.parse_borrowed_pointee())
1333 } else if self.check_keyword(keywords
::For
) {
1334 try
!(self.parse_for_in_type())
1335 } else if self.token_is_bare_fn_keyword() {
1337 try
!(self.parse_ty_bare_fn(Vec
::new()))
1338 } else if try
!(self.eat_keyword_noexpect(keywords
::Typeof
)) {
1340 // In order to not be ambiguous, the type must be surrounded by parens.
1341 try
!(self.expect(&token
::OpenDelim(token
::Paren
)));
1342 let e
= try
!(self.parse_expr_nopanic());
1343 try
!(self.expect(&token
::CloseDelim(token
::Paren
)));
1345 } else if try
!(self.eat_lt()) {
1348 try
!(self.parse_qualified_path(NoTypesAllowed
));
1350 TyPath(Some(qself
), path
)
1351 } else if self.check(&token
::ModSep
) ||
1352 self.token
.is_ident() ||
1353 self.token
.is_path() {
1355 try
!(self.parse_ty_path())
1356 } else if try
!(self.eat(&token
::Underscore
) ){
1357 // TYPE TO BE INFERRED
1360 let this_token_str
= self.this_token_to_string();
1361 let msg
= format
!("expected type, found `{}`", this_token_str
);
1362 return Err(self.fatal(&msg
[..]));
1365 let sp
= mk_sp(lo
, self.last_span
.hi
);
1366 Ok(P(Ty {id: ast::DUMMY_NODE_ID, node: t, span: sp}
))
1369 pub fn parse_borrowed_pointee(&mut self) -> PResult
<Ty_
> {
1370 // look for `&'lt` or `&'foo ` and interpret `foo` as the region name:
1371 let opt_lifetime
= try
!(self.parse_opt_lifetime());
1373 let mt
= try
!(self.parse_mt());
1374 return Ok(TyRptr(opt_lifetime
, mt
));
1377 pub fn parse_ptr(&mut self) -> PResult
<MutTy
> {
1378 let mutbl
= if try
!(self.eat_keyword(keywords
::Mut
) ){
1380 } else if try
!(self.eat_keyword(keywords
::Const
) ){
1383 let span
= self.last_span
;
1385 "bare raw pointers are no longer allowed, you should \
1386 likely use `*mut T`, but otherwise `*T` is now \
1387 known as `*const T`");
1390 let t
= try
!(self.parse_ty_nopanic());
1391 Ok(MutTy { ty: t, mutbl: mutbl }
)
1394 pub fn is_named_argument(&mut self) -> bool
{
1395 let offset
= match self.token
{
1396 token
::BinOp(token
::And
) => 1,
1398 _
if self.token
.is_keyword(keywords
::Mut
) => 1,
1402 debug
!("parser is_named_argument offset:{}", offset
);
1405 is_plain_ident_or_underscore(&self.token
)
1406 && self.look_ahead(1, |t
| *t
== token
::Colon
)
1408 self.look_ahead(offset
, |t
| is_plain_ident_or_underscore(t
))
1409 && self.look_ahead(offset
+ 1, |t
| *t
== token
::Colon
)
1413 /// This version of parse arg doesn't necessarily require
1414 /// identifier names.
1415 pub fn parse_arg_general(&mut self, require_name
: bool
) -> PResult
<Arg
> {
1416 let pat
= if require_name
|| self.is_named_argument() {
1417 debug
!("parse_arg_general parse_pat (require_name:{})",
1419 let pat
= try
!(self.parse_pat_nopanic());
1421 try
!(self.expect(&token
::Colon
));
1424 debug
!("parse_arg_general ident_to_pat");
1425 ast_util
::ident_to_pat(ast
::DUMMY_NODE_ID
,
1427 special_idents
::invalid
)
1430 let t
= try
!(self.parse_ty_sum());
1435 id
: ast
::DUMMY_NODE_ID
,
1439 /// Parse a single function argument
1440 pub fn parse_arg(&mut self) -> PResult
<Arg
> {
1441 self.parse_arg_general(true)
1444 /// Parse an argument in a lambda header e.g. |arg, arg|
1445 pub fn parse_fn_block_arg(&mut self) -> PResult
<Arg
> {
1446 let pat
= try
!(self.parse_pat_nopanic());
1447 let t
= if try
!(self.eat(&token
::Colon
) ){
1448 try
!(self.parse_ty_sum())
1451 id
: ast
::DUMMY_NODE_ID
,
1453 span
: mk_sp(self.span
.lo
, self.span
.hi
),
1459 id
: ast
::DUMMY_NODE_ID
1463 pub fn maybe_parse_fixed_length_of_vec(&mut self) -> PResult
<Option
<P
<ast
::Expr
>>> {
1464 if self.check(&token
::Semi
) {
1466 Ok(Some(try
!(self.parse_expr_nopanic())))
1472 /// Matches token_lit = LIT_INTEGER | ...
1473 pub fn lit_from_token(&self, tok
: &token
::Token
) -> PResult
<Lit_
> {
1475 token
::Interpolated(token
::NtExpr(ref v
)) => {
1477 ExprLit(ref lit
) => { Ok(lit.node.clone()) }
1478 _
=> { return Err(self.unexpected_last(tok)); }
1481 token
::Literal(lit
, suf
) => {
1482 let (suffix_illegal
, out
) = match lit
{
1483 token
::Byte(i
) => (true, LitByte(parse
::byte_lit(i
.as_str()).0)),
1484 token
::Char(i
) => (true, LitChar(parse
::char_lit(i
.as_str()).0)),
1486 // there are some valid suffixes for integer and
1487 // float literals, so all the handling is done
1489 token
::Integer(s
) => {
1490 (false, parse
::integer_lit(s
.as_str(),
1491 suf
.as_ref().map(|s
| s
.as_str()),
1492 &self.sess
.span_diagnostic
,
1495 token
::Float(s
) => {
1496 (false, parse
::float_lit(s
.as_str(),
1497 suf
.as_ref().map(|s
| s
.as_str()),
1498 &self.sess
.span_diagnostic
,
1504 LitStr(token
::intern_and_get_ident(&parse
::str_lit(s
.as_str())),
1507 token
::StrRaw(s
, n
) => {
1510 token
::intern_and_get_ident(&parse
::raw_str_lit(s
.as_str())),
1514 (true, LitBinary(parse
::binary_lit(i
.as_str()))),
1515 token
::BinaryRaw(i
, _
) =>
1517 LitBinary(Rc
::new(i
.as_str().as_bytes().iter().cloned().collect()))),
1521 let sp
= self.last_span
;
1522 self.expect_no_suffix(sp
, &*format
!("{} literal", lit
.short_name()), suf
)
1527 _
=> { return Err(self.unexpected_last(tok)); }
1531 /// Matches lit = true | false | token_lit
1532 pub fn parse_lit(&mut self) -> PResult
<Lit
> {
1533 let lo
= self.span
.lo
;
1534 let lit
= if try
!(self.eat_keyword(keywords
::True
) ){
1536 } else if try
!(self.eat_keyword(keywords
::False
) ){
1539 let token
= try
!(self.bump_and_get());
1540 let lit
= try
!(self.lit_from_token(&token
));
1543 Ok(codemap
::Spanned { node: lit, span: mk_sp(lo, self.last_span.hi) }
)
1546 /// matches '-' lit | lit
1547 pub fn parse_literal_maybe_minus(&mut self) -> PResult
<P
<Expr
>> {
1548 let minus_lo
= self.span
.lo
;
1549 let minus_present
= try
!(self.eat(&token
::BinOp(token
::Minus
)));
1551 let lo
= self.span
.lo
;
1552 let literal
= P(try
!(self.parse_lit()));
1553 let hi
= self.span
.hi
;
1554 let expr
= self.mk_expr(lo
, hi
, ExprLit(literal
));
1557 let minus_hi
= self.span
.hi
;
1558 let unary
= self.mk_unary(UnNeg
, expr
);
1559 Ok(self.mk_expr(minus_lo
, minus_hi
, unary
))
1565 // QUALIFIED PATH `<TYPE [as TRAIT_REF]>::IDENT[::<PARAMS>]`
1566 // Assumes that the leading `<` has been parsed already.
1567 pub fn parse_qualified_path(&mut self, mode
: PathParsingMode
)
1568 -> PResult
<(QSelf
, ast
::Path
)> {
1569 let self_type
= try
!(self.parse_ty_sum());
1570 let mut path
= if try
!(self.eat_keyword(keywords
::As
)) {
1571 try
!(self.parse_path(LifetimeAndTypesWithoutColons
))
1582 position
: path
.segments
.len()
1585 try
!(self.expect(&token
::Gt
));
1586 try
!(self.expect(&token
::ModSep
));
1588 let segments
= match mode
{
1589 LifetimeAndTypesWithoutColons
=> {
1590 try
!(self.parse_path_segments_without_colons())
1592 LifetimeAndTypesWithColons
=> {
1593 try
!(self.parse_path_segments_with_colons())
1596 try
!(self.parse_path_segments_without_types())
1599 path
.segments
.extend(segments
);
1601 if path
.segments
.len() == 1 {
1602 path
.span
.lo
= self.last_span
.lo
;
1604 path
.span
.hi
= self.last_span
.hi
;
1609 /// Parses a path and optional type parameter bounds, depending on the
1610 /// mode. The `mode` parameter determines whether lifetimes, types, and/or
1611 /// bounds are permitted and whether `::` must precede type parameter
1613 pub fn parse_path(&mut self, mode
: PathParsingMode
) -> PResult
<ast
::Path
> {
1614 // Check for a whole path...
1615 let found
= match self.token
{
1616 token
::Interpolated(token
::NtPath(_
)) => Some(try
!(self.bump_and_get())),
1619 if let Some(token
::Interpolated(token
::NtPath(path
))) = found
{
1623 let lo
= self.span
.lo
;
1624 let is_global
= try
!(self.eat(&token
::ModSep
));
1626 // Parse any number of segments and bound sets. A segment is an
1627 // identifier followed by an optional lifetime and a set of types.
1628 // A bound set is a set of type parameter bounds.
1629 let segments
= match mode
{
1630 LifetimeAndTypesWithoutColons
=> {
1631 try
!(self.parse_path_segments_without_colons())
1633 LifetimeAndTypesWithColons
=> {
1634 try
!(self.parse_path_segments_with_colons())
1637 try
!(self.parse_path_segments_without_types())
1641 // Assemble the span.
1642 let span
= mk_sp(lo
, self.last_span
.hi
);
1644 // Assemble the result.
1653 /// - `a::b<T,U>::c<V,W>`
1654 /// - `a::b<T,U>::c(V) -> W`
1655 /// - `a::b<T,U>::c(V)`
1656 pub fn parse_path_segments_without_colons(&mut self) -> PResult
<Vec
<ast
::PathSegment
>> {
1657 let mut segments
= Vec
::new();
1659 // First, parse an identifier.
1660 let identifier
= try
!(self.parse_ident_or_self_type());
1662 // Parse types, optionally.
1663 let parameters
= if try
!(self.eat_lt() ){
1664 let (lifetimes
, types
, bindings
) = try
!(self.parse_generic_values_after_lt());
1666 ast
::AngleBracketedParameters(ast
::AngleBracketedParameterData
{
1667 lifetimes
: lifetimes
,
1668 types
: OwnedSlice
::from_vec(types
),
1669 bindings
: OwnedSlice
::from_vec(bindings
),
1671 } else if try
!(self.eat(&token
::OpenDelim(token
::Paren
)) ){
1672 let lo
= self.last_span
.lo
;
1674 let inputs
= try
!(self.parse_seq_to_end(
1675 &token
::CloseDelim(token
::Paren
),
1676 seq_sep_trailing_allowed(token
::Comma
),
1677 |p
| p
.parse_ty_sum()));
1679 let output_ty
= if try
!(self.eat(&token
::RArrow
) ){
1680 Some(try
!(self.parse_ty_nopanic()))
1685 let hi
= self.last_span
.hi
;
1687 ast
::ParenthesizedParameters(ast
::ParenthesizedParameterData
{
1688 span
: mk_sp(lo
, hi
),
1693 ast
::PathParameters
::none()
1696 // Assemble and push the result.
1697 segments
.push(ast
::PathSegment
{ identifier
: identifier
,
1698 parameters
: parameters
});
1700 // Continue only if we see a `::`
1701 if !try
!(self.eat(&token
::ModSep
) ){
1702 return Ok(segments
);
1708 /// - `a::b::<T,U>::c`
1709 pub fn parse_path_segments_with_colons(&mut self) -> PResult
<Vec
<ast
::PathSegment
>> {
1710 let mut segments
= Vec
::new();
1712 // First, parse an identifier.
1713 let identifier
= try
!(self.parse_ident_or_self_type());
1715 // If we do not see a `::`, stop.
1716 if !try
!(self.eat(&token
::ModSep
) ){
1717 segments
.push(ast
::PathSegment
{
1718 identifier
: identifier
,
1719 parameters
: ast
::PathParameters
::none()
1721 return Ok(segments
);
1724 // Check for a type segment.
1725 if try
!(self.eat_lt() ){
1726 // Consumed `a::b::<`, go look for types
1727 let (lifetimes
, types
, bindings
) = try
!(self.parse_generic_values_after_lt());
1728 segments
.push(ast
::PathSegment
{
1729 identifier
: identifier
,
1730 parameters
: ast
::AngleBracketedParameters(ast
::AngleBracketedParameterData
{
1731 lifetimes
: lifetimes
,
1732 types
: OwnedSlice
::from_vec(types
),
1733 bindings
: OwnedSlice
::from_vec(bindings
),
1737 // Consumed `a::b::<T,U>`, check for `::` before proceeding
1738 if !try
!(self.eat(&token
::ModSep
) ){
1739 return Ok(segments
);
1742 // Consumed `a::`, go look for `b`
1743 segments
.push(ast
::PathSegment
{
1744 identifier
: identifier
,
1745 parameters
: ast
::PathParameters
::none(),
1754 pub fn parse_path_segments_without_types(&mut self) -> PResult
<Vec
<ast
::PathSegment
>> {
1755 let mut segments
= Vec
::new();
1757 // First, parse an identifier.
1758 let identifier
= try
!(self.parse_ident_or_self_type());
1760 // Assemble and push the result.
1761 segments
.push(ast
::PathSegment
{
1762 identifier
: identifier
,
1763 parameters
: ast
::PathParameters
::none()
1766 // If we do not see a `::`, stop.
1767 if !try
!(self.eat(&token
::ModSep
) ){
1768 return Ok(segments
);
1773 /// parses 0 or 1 lifetime
1774 pub fn parse_opt_lifetime(&mut self) -> PResult
<Option
<ast
::Lifetime
>> {
1776 token
::Lifetime(..) => {
1777 Ok(Some(try
!(self.parse_lifetime())))
1785 /// Parses a single lifetime
1786 /// Matches lifetime = LIFETIME
1787 pub fn parse_lifetime(&mut self) -> PResult
<ast
::Lifetime
> {
1789 token
::Lifetime(i
) => {
1790 let span
= self.span
;
1792 return Ok(ast
::Lifetime
{
1793 id
: ast
::DUMMY_NODE_ID
,
1799 return Err(self.fatal(&format
!("expected a lifetime name")));
1804 /// Parses `lifetime_defs = [ lifetime_defs { ',' lifetime_defs } ]` where `lifetime_def =
1805 /// lifetime [':' lifetimes]`
1806 pub fn parse_lifetime_defs(&mut self) -> PResult
<Vec
<ast
::LifetimeDef
>> {
1808 let mut res
= Vec
::new();
1811 token
::Lifetime(_
) => {
1812 let lifetime
= try
!(self.parse_lifetime());
1814 if try
!(self.eat(&token
::Colon
) ){
1815 try
!(self.parse_lifetimes(token
::BinOp(token
::Plus
)))
1819 res
.push(ast
::LifetimeDef
{ lifetime
: lifetime
,
1829 token
::Comma
=> { try!(self.bump());}
1830 token
::Gt
=> { return Ok(res); }
1831 token
::BinOp(token
::Shr
) => { return Ok(res); }
1833 let this_token_str
= self.this_token_to_string();
1834 let msg
= format
!("expected `,` or `>` after lifetime \
1837 return Err(self.fatal(&msg
[..]));
1843 /// matches lifetimes = ( lifetime ) | ( lifetime , lifetimes ) actually, it matches the empty
1844 /// one too, but putting that in there messes up the grammar....
1846 /// Parses zero or more comma separated lifetimes. Expects each lifetime to be followed by
1847 /// either a comma or `>`. Used when parsing type parameter lists, where we expect something
1848 /// like `<'a, 'b, T>`.
1849 pub fn parse_lifetimes(&mut self, sep
: token
::Token
) -> PResult
<Vec
<ast
::Lifetime
>> {
1851 let mut res
= Vec
::new();
1854 token
::Lifetime(_
) => {
1855 res
.push(try
!(self.parse_lifetime()));
1862 if self.token
!= sep
{
1870 /// Parse mutability declaration (mut/const/imm)
1871 pub fn parse_mutability(&mut self) -> PResult
<Mutability
> {
1872 if try
!(self.eat_keyword(keywords
::Mut
) ){
1879 /// Parse ident COLON expr
1880 pub fn parse_field(&mut self) -> PResult
<Field
> {
1881 let lo
= self.span
.lo
;
1882 let i
= try
!(self.parse_ident());
1883 let hi
= self.last_span
.hi
;
1884 try
!(self.expect(&token
::Colon
));
1885 let e
= try
!(self.parse_expr_nopanic());
1887 ident
: spanned(lo
, hi
, i
),
1888 span
: mk_sp(lo
, e
.span
.hi
),
1893 pub fn mk_expr(&mut self, lo
: BytePos
, hi
: BytePos
, node
: Expr_
) -> P
<Expr
> {
1895 id
: ast
::DUMMY_NODE_ID
,
1897 span
: mk_sp(lo
, hi
),
1901 pub fn mk_unary(&mut self, unop
: ast
::UnOp
, expr
: P
<Expr
>) -> ast
::Expr_
{
1902 ExprUnary(unop
, expr
)
1905 pub fn mk_binary(&mut self, binop
: ast
::BinOp
, lhs
: P
<Expr
>, rhs
: P
<Expr
>) -> ast
::Expr_
{
1906 ExprBinary(binop
, lhs
, rhs
)
1909 pub fn mk_call(&mut self, f
: P
<Expr
>, args
: Vec
<P
<Expr
>>) -> ast
::Expr_
{
1913 fn mk_method_call(&mut self,
1914 ident
: ast
::SpannedIdent
,
1918 ExprMethodCall(ident
, tps
, args
)
1921 pub fn mk_index(&mut self, expr
: P
<Expr
>, idx
: P
<Expr
>) -> ast
::Expr_
{
1922 ExprIndex(expr
, idx
)
1925 pub fn mk_range(&mut self,
1926 start
: Option
<P
<Expr
>>,
1927 end
: Option
<P
<Expr
>>)
1929 ExprRange(start
, end
)
1932 pub fn mk_field(&mut self, expr
: P
<Expr
>, ident
: ast
::SpannedIdent
) -> ast
::Expr_
{
1933 ExprField(expr
, ident
)
1936 pub fn mk_tup_field(&mut self, expr
: P
<Expr
>, idx
: codemap
::Spanned
<usize>) -> ast
::Expr_
{
1937 ExprTupField(expr
, idx
)
1940 pub fn mk_assign_op(&mut self, binop
: ast
::BinOp
,
1941 lhs
: P
<Expr
>, rhs
: P
<Expr
>) -> ast
::Expr_
{
1942 ExprAssignOp(binop
, lhs
, rhs
)
1945 pub fn mk_mac_expr(&mut self, lo
: BytePos
, hi
: BytePos
, m
: Mac_
) -> P
<Expr
> {
1947 id
: ast
::DUMMY_NODE_ID
,
1948 node
: ExprMac(codemap
::Spanned {node: m, span: mk_sp(lo, hi)}
),
1949 span
: mk_sp(lo
, hi
),
1953 pub fn mk_lit_u32(&mut self, i
: u32) -> P
<Expr
> {
1954 let span
= &self.span
;
1955 let lv_lit
= P(codemap
::Spanned
{
1956 node
: LitInt(i
as u64, ast
::UnsignedIntLit(TyU32
)),
1961 id
: ast
::DUMMY_NODE_ID
,
1962 node
: ExprLit(lv_lit
),
1967 fn expect_open_delim(&mut self) -> PResult
<token
::DelimToken
> {
1968 self.expected_tokens
.push(TokenType
::Token(token
::Gt
));
1970 token
::OpenDelim(delim
) => {
1974 _
=> Err(self.fatal("expected open delimiter")),
1978 /// At the bottom (top?) of the precedence hierarchy,
1979 /// parse things like parenthesized exprs,
1980 /// macros, return, etc.
1981 pub fn parse_bottom_expr(&mut self) -> PResult
<P
<Expr
>> {
1982 maybe_whole_expr
!(self);
1984 let lo
= self.span
.lo
;
1985 let mut hi
= self.span
.hi
;
1989 // Note: when adding new syntax here, don't forget to adjust Token::can_begin_expr().
1991 token
::OpenDelim(token
::Paren
) => {
1994 // (e) is parenthesized e
1995 // (e,) is a tuple with only one field, e
1996 let mut es
= vec
![];
1997 let mut trailing_comma
= false;
1998 while self.token
!= token
::CloseDelim(token
::Paren
) {
1999 es
.push(try
!(self.parse_expr_nopanic()));
2000 try
!(self.commit_expr(&**es
.last().unwrap(), &[],
2001 &[token
::Comma
, token
::CloseDelim(token
::Paren
)]));
2002 if self.check(&token
::Comma
) {
2003 trailing_comma
= true;
2007 trailing_comma
= false;
2013 hi
= self.last_span
.hi
;
2014 return if es
.len() == 1 && !trailing_comma
{
2015 Ok(self.mk_expr(lo
, hi
, ExprParen(es
.into_iter().nth(0).unwrap())))
2017 Ok(self.mk_expr(lo
, hi
, ExprTup(es
)))
2020 token
::OpenDelim(token
::Brace
) => {
2021 return self.parse_block_expr(lo
, DefaultBlock
);
2023 token
::BinOp(token
::Or
) | token
::OrOr
=> {
2024 let lo
= self.span
.lo
;
2025 return self.parse_lambda_expr(lo
, CaptureByRef
);
2027 token
::Ident(id @ ast
::Ident
{
2028 name
: token
::SELF_KEYWORD_NAME
,
2030 }, token
::Plain
) => {
2032 let path
= ast_util
::ident_to_path(mk_sp(lo
, hi
), id
);
2033 ex
= ExprPath(None
, path
);
2034 hi
= self.last_span
.hi
;
2036 token
::OpenDelim(token
::Bracket
) => {
2039 if self.check(&token
::CloseDelim(token
::Bracket
)) {
2042 ex
= ExprVec(Vec
::new());
2045 let first_expr
= try
!(self.parse_expr_nopanic());
2046 if self.check(&token
::Semi
) {
2047 // Repeating vector syntax: [ 0; 512 ]
2049 let count
= try
!(self.parse_expr_nopanic());
2050 try
!(self.expect(&token
::CloseDelim(token
::Bracket
)));
2051 ex
= ExprRepeat(first_expr
, count
);
2052 } else if self.check(&token
::Comma
) {
2053 // Vector with two or more elements.
2055 let remaining_exprs
= try
!(self.parse_seq_to_end(
2056 &token
::CloseDelim(token
::Bracket
),
2057 seq_sep_trailing_allowed(token
::Comma
),
2058 |p
| Ok(try
!(p
.parse_expr_nopanic()))
2060 let mut exprs
= vec
!(first_expr
);
2061 exprs
.extend(remaining_exprs
);
2062 ex
= ExprVec(exprs
);
2064 // Vector with one element.
2065 try
!(self.expect(&token
::CloseDelim(token
::Bracket
)));
2066 ex
= ExprVec(vec
!(first_expr
));
2069 hi
= self.last_span
.hi
;
2072 if try
!(self.eat_lt()){
2074 try
!(self.parse_qualified_path(LifetimeAndTypesWithColons
));
2076 return Ok(self.mk_expr(lo
, hi
, ExprPath(Some(qself
), path
)));
2078 if try
!(self.eat_keyword(keywords
::Move
) ){
2079 let lo
= self.last_span
.lo
;
2080 return self.parse_lambda_expr(lo
, CaptureByValue
);
2082 if try
!(self.eat_keyword(keywords
::If
)) {
2083 return self.parse_if_expr();
2085 if try
!(self.eat_keyword(keywords
::For
) ){
2086 return self.parse_for_expr(None
);
2088 if try
!(self.eat_keyword(keywords
::While
) ){
2089 return self.parse_while_expr(None
);
2091 if self.token
.is_lifetime() {
2092 let lifetime
= self.get_lifetime();
2094 try
!(self.expect(&token
::Colon
));
2095 if try
!(self.eat_keyword(keywords
::While
) ){
2096 return self.parse_while_expr(Some(lifetime
))
2098 if try
!(self.eat_keyword(keywords
::For
) ){
2099 return self.parse_for_expr(Some(lifetime
))
2101 if try
!(self.eat_keyword(keywords
::Loop
) ){
2102 return self.parse_loop_expr(Some(lifetime
))
2104 return Err(self.fatal("expected `while`, `for`, or `loop` after a label"))
2106 if try
!(self.eat_keyword(keywords
::Loop
) ){
2107 return self.parse_loop_expr(None
);
2109 if try
!(self.eat_keyword(keywords
::Continue
) ){
2110 let lo
= self.span
.lo
;
2111 let ex
= if self.token
.is_lifetime() {
2112 let lifetime
= self.get_lifetime();
2114 ExprAgain(Some(lifetime
))
2118 let hi
= self.span
.hi
;
2119 return Ok(self.mk_expr(lo
, hi
, ex
));
2121 if try
!(self.eat_keyword(keywords
::Match
) ){
2122 return self.parse_match_expr();
2124 if try
!(self.eat_keyword(keywords
::Unsafe
) ){
2125 return self.parse_block_expr(
2127 UnsafeBlock(ast
::UserProvided
));
2129 if try
!(self.eat_keyword(keywords
::Return
) ){
2130 // RETURN expression
2131 if self.token
.can_begin_expr() {
2132 let e
= try
!(self.parse_expr_nopanic());
2134 ex
= ExprRet(Some(e
));
2138 } else if try
!(self.eat_keyword(keywords
::Break
) ){
2140 if self.token
.is_lifetime() {
2141 let lifetime
= self.get_lifetime();
2143 ex
= ExprBreak(Some(lifetime
));
2145 ex
= ExprBreak(None
);
2148 } else if self.check(&token
::ModSep
) ||
2149 self.token
.is_ident() &&
2150 !self.check_keyword(keywords
::True
) &&
2151 !self.check_keyword(keywords
::False
) {
2153 try
!(self.parse_path(LifetimeAndTypesWithColons
));
2155 // `!`, as an operator, is prefix, so we know this isn't that
2156 if self.check(&token
::Not
) {
2157 // MACRO INVOCATION expression
2160 let delim
= try
!(self.expect_open_delim());
2161 let tts
= try
!(self.parse_seq_to_end(
2162 &token
::CloseDelim(delim
),
2164 |p
| p
.parse_token_tree()));
2165 let hi
= self.last_span
.hi
;
2167 return Ok(self.mk_mac_expr(lo
,
2173 if self.check(&token
::OpenDelim(token
::Brace
)) {
2174 // This is a struct literal, unless we're prohibited
2175 // from parsing struct literals here.
2176 let prohibited
= self.restrictions
.contains(
2177 Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
2180 // It's a struct literal.
2182 let mut fields
= Vec
::new();
2183 let mut base
= None
;
2185 while self.token
!= token
::CloseDelim(token
::Brace
) {
2186 if try
!(self.eat(&token
::DotDot
) ){
2187 base
= Some(try
!(self.parse_expr_nopanic()));
2191 fields
.push(try
!(self.parse_field()));
2192 try
!(self.commit_expr(&*fields
.last().unwrap().expr
,
2194 &[token
::CloseDelim(token
::Brace
)]));
2197 if fields
.is_empty() && base
.is_none() {
2198 let last_span
= self.last_span
;
2199 self.span_err(last_span
,
2200 "structure literal must either \
2201 have at least one field or use \
2202 functional structure update \
2207 try
!(self.expect(&token
::CloseDelim(token
::Brace
)));
2208 ex
= ExprStruct(pth
, fields
, base
);
2209 return Ok(self.mk_expr(lo
, hi
, ex
));
2214 ex
= ExprPath(None
, pth
);
2216 // other literal expression
2217 let lit
= try
!(self.parse_lit());
2219 ex
= ExprLit(P(lit
));
2224 return Ok(self.mk_expr(lo
, hi
, ex
));
2227 /// Parse a block or unsafe block
2228 pub fn parse_block_expr(&mut self, lo
: BytePos
, blk_mode
: BlockCheckMode
)
2229 -> PResult
<P
<Expr
>> {
2230 try
!(self.expect(&token
::OpenDelim(token
::Brace
)));
2231 let blk
= try
!(self.parse_block_tail(lo
, blk_mode
));
2232 return Ok(self.mk_expr(blk
.span
.lo
, blk
.span
.hi
, ExprBlock(blk
)));
2235 /// parse a.b or a(13) or a[4] or just a
2236 pub fn parse_dot_or_call_expr(&mut self) -> PResult
<P
<Expr
>> {
2237 let b
= try
!(self.parse_bottom_expr());
2238 self.parse_dot_or_call_expr_with(b
)
2241 pub fn parse_dot_or_call_expr_with(&mut self, e0
: P
<Expr
>) -> PResult
<P
<Expr
>> {
2247 if try
!(self.eat(&token
::Dot
) ){
2249 token
::Ident(i
, _
) => {
2250 let dot
= self.last_span
.hi
;
2253 let (_
, tys
, bindings
) = if try
!(self.eat(&token
::ModSep
) ){
2254 try
!(self.expect_lt());
2255 try
!(self.parse_generic_values_after_lt())
2257 (Vec
::new(), Vec
::new(), Vec
::new())
2260 if !bindings
.is_empty() {
2261 let last_span
= self.last_span
;
2262 self.span_err(last_span
, "type bindings are only permitted on trait paths");
2265 // expr.f() method call
2267 token
::OpenDelim(token
::Paren
) => {
2268 let mut es
= try
!(self.parse_unspanned_seq(
2269 &token
::OpenDelim(token
::Paren
),
2270 &token
::CloseDelim(token
::Paren
),
2271 seq_sep_trailing_allowed(token
::Comma
),
2272 |p
| Ok(try
!(p
.parse_expr_nopanic()))
2274 hi
= self.last_span
.hi
;
2277 let id
= spanned(dot
, hi
, i
);
2278 let nd
= self.mk_method_call(id
, tys
, es
);
2279 e
= self.mk_expr(lo
, hi
, nd
);
2282 if !tys
.is_empty() {
2283 let last_span
= self.last_span
;
2284 self.span_err(last_span
,
2285 "field expressions may not \
2286 have type parameters");
2289 let id
= spanned(dot
, hi
, i
);
2290 let field
= self.mk_field(e
, id
);
2291 e
= self.mk_expr(lo
, hi
, field
);
2295 token
::Literal(token
::Integer(n
), suf
) => {
2298 // A tuple index may not have a suffix
2299 self.expect_no_suffix(sp
, "tuple index", suf
);
2301 let dot
= self.last_span
.hi
;
2305 let index
= n
.as_str().parse
::<usize>().ok();
2308 let id
= spanned(dot
, hi
, n
);
2309 let field
= self.mk_tup_field(e
, id
);
2310 e
= self.mk_expr(lo
, hi
, field
);
2313 let last_span
= self.last_span
;
2314 self.span_err(last_span
, "invalid tuple or tuple struct index");
2318 token
::Literal(token
::Float(n
), _suf
) => {
2320 let last_span
= self.last_span
;
2321 let fstr
= n
.as_str();
2322 self.span_err(last_span
,
2323 &format
!("unexpected token: `{}`", n
.as_str()));
2324 if fstr
.chars().all(|x
| "0123456789.".contains(x
)) {
2325 let float
= match fstr
.parse
::<f64>().ok() {
2329 self.fileline_help(last_span
,
2330 &format
!("try parenthesizing the first index; e.g., `(foo.{}){}`",
2331 float
.trunc() as usize,
2332 &float
.fract().to_string()[1..]));
2334 self.abort_if_errors();
2337 _
=> return Err(self.unexpected())
2341 if self.expr_is_complete(&*e
) { break; }
2344 token
::OpenDelim(token
::Paren
) => {
2345 let es
= try
!(self.parse_unspanned_seq(
2346 &token
::OpenDelim(token
::Paren
),
2347 &token
::CloseDelim(token
::Paren
),
2348 seq_sep_trailing_allowed(token
::Comma
),
2349 |p
| Ok(try
!(p
.parse_expr_nopanic()))
2351 hi
= self.last_span
.hi
;
2353 let nd
= self.mk_call(e
, es
);
2354 e
= self.mk_expr(lo
, hi
, nd
);
2358 // Could be either an index expression or a slicing expression.
2359 token
::OpenDelim(token
::Bracket
) => {
2361 let ix
= try
!(self.parse_expr_nopanic());
2363 try
!(self.commit_expr_expecting(&*ix
, token
::CloseDelim(token
::Bracket
)));
2364 let index
= self.mk_index(e
, ix
);
2365 e
= self.mk_expr(lo
, hi
, index
)
2373 // Parse unquoted tokens after a `$` in a token tree
2374 fn parse_unquoted(&mut self) -> PResult
<TokenTree
> {
2375 let mut sp
= self.span
;
2376 let (name
, namep
) = match self.token
{
2380 if self.token
== token
::OpenDelim(token
::Paren
) {
2381 let Spanned { node: seq, span: seq_span }
= try
!(self.parse_seq(
2382 &token
::OpenDelim(token
::Paren
),
2383 &token
::CloseDelim(token
::Paren
),
2385 |p
| p
.parse_token_tree()
2387 let (sep
, repeat
) = try
!(self.parse_sep_and_kleene_op());
2388 let name_num
= macro_parser
::count_names(&seq
);
2389 return Ok(TtSequence(mk_sp(sp
.lo
, seq_span
.hi
),
2390 Rc
::new(SequenceRepetition
{
2394 num_captures
: name_num
2396 } else if self.token
.is_keyword_allow_following_colon(keywords
::Crate
) {
2398 return Ok(TtToken(sp
, SpecialVarNt(SpecialMacroVar
::CrateMacroVar
)));
2400 sp
= mk_sp(sp
.lo
, self.span
.hi
);
2401 let namep
= match self.token { token::Ident(_, p) => p, _ => token::Plain }
;
2402 let name
= try
!(self.parse_ident());
2406 token
::SubstNt(name
, namep
) => {
2412 // continue by trying to parse the `:ident` after `$name`
2413 if self.token
== token
::Colon
&& self.look_ahead(1, |t
| t
.is_ident() &&
2414 !t
.is_strict_keyword() &&
2415 !t
.is_reserved_keyword()) {
2417 sp
= mk_sp(sp
.lo
, self.span
.hi
);
2418 let kindp
= match self.token { token::Ident(_, p) => p, _ => token::Plain }
;
2419 let nt_kind
= try
!(self.parse_ident());
2420 Ok(TtToken(sp
, MatchNt(name
, nt_kind
, namep
, kindp
)))
2422 Ok(TtToken(sp
, SubstNt(name
, namep
)))
2426 pub fn check_unknown_macro_variable(&mut self) -> PResult
<()> {
2427 if self.quote_depth
== 0 {
2429 token
::SubstNt(name
, _
) =>
2430 return Err(self.fatal(&format
!("unknown macro variable `{}`",
2431 token
::get_ident(name
)))),
2438 /// Parse an optional separator followed by a Kleene-style
2439 /// repetition token (+ or *).
2440 pub fn parse_sep_and_kleene_op(&mut self) -> PResult
<(Option
<token
::Token
>, ast
::KleeneOp
)> {
2441 fn parse_kleene_op(parser
: &mut Parser
) -> PResult
<Option
<ast
::KleeneOp
>> {
2442 match parser
.token
{
2443 token
::BinOp(token
::Star
) => {
2444 try
!(parser
.bump());
2445 Ok(Some(ast
::ZeroOrMore
))
2447 token
::BinOp(token
::Plus
) => {
2448 try
!(parser
.bump());
2449 Ok(Some(ast
::OneOrMore
))
2455 match try
!(parse_kleene_op(self)) {
2456 Some(kleene_op
) => return Ok((None
, kleene_op
)),
2460 let separator
= try
!(self.bump_and_get());
2461 match try
!(parse_kleene_op(self)) {
2462 Some(zerok
) => Ok((Some(separator
), zerok
)),
2463 None
=> return Err(self.fatal("expected `*` or `+`"))
2467 /// parse a single token tree from the input.
2468 pub fn parse_token_tree(&mut self) -> PResult
<TokenTree
> {
2469 // FIXME #6994: currently, this is too eager. It
2470 // parses token trees but also identifies TtSequence's
2471 // and token::SubstNt's; it's too early to know yet
2472 // whether something will be a nonterminal or a seq
2474 maybe_whole
!(deref
self, NtTT
);
2476 // this is the fall-through for the 'match' below.
2477 // invariants: the current token is not a left-delimiter,
2478 // not an EOF, and not the desired right-delimiter (if
2479 // it were, parse_seq_to_before_end would have prevented
2480 // reaching this point.
2481 fn parse_non_delim_tt_tok(p
: &mut Parser
) -> PResult
<TokenTree
> {
2482 maybe_whole
!(deref p
, NtTT
);
2484 token
::CloseDelim(_
) => {
2485 // This is a conservative error: only report the last unclosed delimiter. The
2486 // previous unclosed delimiters could actually be closed! The parser just hasn't
2487 // gotten to them yet.
2488 match p
.open_braces
.last() {
2490 Some(&sp
) => p
.span_note(sp
, "unclosed delimiter"),
2492 let token_str
= p
.this_token_to_string();
2493 Err(p
.fatal(&format
!("incorrect close delimiter: `{}`",
2496 /* we ought to allow different depths of unquotation */
2497 token
::Dollar
| token
::SubstNt(..) if p
.quote_depth
> 0 => {
2501 Ok(TtToken(p
.span
, try
!(p
.bump_and_get())))
2508 let open_braces
= self.open_braces
.clone();
2509 for sp
in &open_braces
{
2510 self.span_help(*sp
, "did you mean to close this delimiter?");
2512 // There shouldn't really be a span, but it's easier for the test runner
2513 // if we give it one
2514 return Err(self.fatal("this file contains an un-closed delimiter "));
2516 token
::OpenDelim(delim
) => {
2517 // The span for beginning of the delimited section
2518 let pre_span
= self.span
;
2520 // Parse the open delimiter.
2521 self.open_braces
.push(self.span
);
2522 let open_span
= self.span
;
2525 // Parse the token trees within the delimiters
2526 let tts
= try
!(self.parse_seq_to_before_end(
2527 &token
::CloseDelim(delim
),
2529 |p
| p
.parse_token_tree()
2532 // Parse the close delimiter.
2533 let close_span
= self.span
;
2535 self.open_braces
.pop().unwrap();
2537 // Expand to cover the entire delimited token tree
2538 let span
= Span { hi: close_span.hi, ..pre_span }
;
2540 Ok(TtDelimited(span
, Rc
::new(Delimited
{
2542 open_span
: open_span
,
2544 close_span
: close_span
,
2547 _
=> parse_non_delim_tt_tok(self),
2551 // parse a stream of tokens into a list of TokenTree's,
2553 pub fn parse_all_token_trees(&mut self) -> PResult
<Vec
<TokenTree
>> {
2554 let mut tts
= Vec
::new();
2555 while self.token
!= token
::Eof
{
2556 tts
.push(try
!(self.parse_token_tree()));
2561 /// Parse a prefix-operator expr
2562 pub fn parse_prefix_expr(&mut self) -> PResult
<P
<Expr
>> {
2563 let lo
= self.span
.lo
;
2566 // Note: when adding new unary operators, don't forget to adjust Token::can_begin_expr()
2571 let e
= try
!(self.parse_prefix_expr());
2573 ex
= self.mk_unary(UnNot
, e
);
2575 token
::BinOp(token
::Minus
) => {
2577 let e
= try
!(self.parse_prefix_expr());
2579 ex
= self.mk_unary(UnNeg
, e
);
2581 token
::BinOp(token
::Star
) => {
2583 let e
= try
!(self.parse_prefix_expr());
2585 ex
= self.mk_unary(UnDeref
, e
);
2587 token
::BinOp(token
::And
) | token
::AndAnd
=> {
2588 try
!(self.expect_and());
2589 let m
= try
!(self.parse_mutability());
2590 let e
= try
!(self.parse_prefix_expr());
2592 ex
= ExprAddrOf(m
, e
);
2594 token
::Ident(_
, _
) => {
2595 if !self.check_keyword(keywords
::Box
) {
2596 return self.parse_dot_or_call_expr();
2599 let lo
= self.span
.lo
;
2600 let box_hi
= self.span
.hi
;
2604 // Check for a place: `box(PLACE) EXPR`.
2605 if try
!(self.eat(&token
::OpenDelim(token
::Paren
)) ){
2606 // Support `box() EXPR` as the default.
2607 if !try
!(self.eat(&token
::CloseDelim(token
::Paren
)) ){
2608 let place
= try
!(self.parse_expr_nopanic());
2609 try
!(self.expect(&token
::CloseDelim(token
::Paren
)));
2610 // Give a suggestion to use `box()` when a parenthesised expression is used
2611 if !self.token
.can_begin_expr() {
2612 let span
= self.span
;
2613 let this_token_to_string
= self.this_token_to_string();
2615 &format
!("expected expression, found `{}`",
2616 this_token_to_string
));
2617 let box_span
= mk_sp(lo
, box_hi
);
2618 self.span_suggestion(box_span
,
2619 "try using `box()` instead:",
2620 "box()".to_string());
2621 self.abort_if_errors();
2623 let subexpression
= try
!(self.parse_prefix_expr());
2624 hi
= subexpression
.span
.hi
;
2625 ex
= ExprBox(Some(place
), subexpression
);
2626 return Ok(self.mk_expr(lo
, hi
, ex
));
2630 // Otherwise, we use the unique pointer default.
2631 let subexpression
= try
!(self.parse_prefix_expr());
2632 hi
= subexpression
.span
.hi
;
2633 // FIXME (pnkfelix): After working out kinks with box
2634 // desugaring, should be `ExprBox(None, subexpression)`
2636 ex
= self.mk_unary(UnUniq
, subexpression
);
2638 _
=> return self.parse_dot_or_call_expr()
2640 return Ok(self.mk_expr(lo
, hi
, ex
));
2643 /// Parse an expression of binops
2644 pub fn parse_binops(&mut self) -> PResult
<P
<Expr
>> {
2645 let prefix_expr
= try
!(self.parse_prefix_expr());
2646 self.parse_more_binops(prefix_expr
, 0)
2649 /// Parse an expression of binops of at least min_prec precedence
2650 pub fn parse_more_binops(&mut self, lhs
: P
<Expr
>, min_prec
: usize) -> PResult
<P
<Expr
>> {
2651 if self.expr_is_complete(&*lhs
) { return Ok(lhs); }
2653 self.expected_tokens
.push(TokenType
::Operator
);
2655 let cur_op_span
= self.span
;
2656 let cur_opt
= self.token
.to_binop();
2659 if ast_util
::is_comparison_binop(cur_op
) {
2660 self.check_no_chained_comparison(&*lhs
, cur_op
)
2662 let cur_prec
= operator_prec(cur_op
);
2663 if cur_prec
>= min_prec
{
2665 let expr
= try
!(self.parse_prefix_expr());
2666 let rhs
= try
!(self.parse_more_binops(expr
, cur_prec
+ 1));
2667 let lhs_span
= lhs
.span
;
2668 let rhs_span
= rhs
.span
;
2669 let binary
= self.mk_binary(codemap
::respan(cur_op_span
, cur_op
), lhs
, rhs
);
2670 let bin
= self.mk_expr(lhs_span
.lo
, rhs_span
.hi
, binary
);
2671 self.parse_more_binops(bin
, min_prec
)
2677 if AS_PREC
>= min_prec
&& try
!(self.eat_keyword_noexpect(keywords
::As
) ){
2678 let rhs
= try
!(self.parse_ty_nopanic());
2679 let _as
= self.mk_expr(lhs
.span
.lo
,
2681 ExprCast(lhs
, rhs
));
2682 self.parse_more_binops(_as
, min_prec
)
2690 /// Produce an error if comparison operators are chained (RFC #558).
2691 /// We only need to check lhs, not rhs, because all comparison ops
2692 /// have same precedence and are left-associative
2693 fn check_no_chained_comparison(&mut self, lhs
: &Expr
, outer_op
: ast
::BinOp_
) {
2694 debug_assert
!(ast_util
::is_comparison_binop(outer_op
));
2696 ExprBinary(op
, _
, _
) if ast_util
::is_comparison_binop(op
.node
) => {
2697 // respan to include both operators
2698 let op_span
= mk_sp(op
.span
.lo
, self.span
.hi
);
2699 self.span_err(op_span
,
2700 "chained comparison operators require parentheses");
2701 if op
.node
== BiLt
&& outer_op
== BiGt
{
2702 self.fileline_help(op_span
,
2703 "use `::<...>` instead of `<...>` if you meant to specify type arguments");
2710 /// Parse an assignment expression....
2711 /// actually, this seems to be the main entry point for
2712 /// parsing an arbitrary expression.
2713 pub fn parse_assign_expr(&mut self) -> PResult
<P
<Expr
>> {
2716 // prefix-form of range notation '..expr'
2717 // This has the same precedence as assignment expressions
2718 // (much lower than other prefix expressions) to be consistent
2719 // with the postfix-form 'expr..'
2720 let lo
= self.span
.lo
;
2722 let opt_end
= if self.is_at_start_of_range_notation_rhs() {
2723 let end
= try
!(self.parse_binops());
2728 let hi
= self.span
.hi
;
2729 let ex
= self.mk_range(None
, opt_end
);
2730 Ok(self.mk_expr(lo
, hi
, ex
))
2733 let lhs
= try
!(self.parse_binops());
2734 self.parse_assign_expr_with(lhs
)
2739 pub fn parse_assign_expr_with(&mut self, lhs
: P
<Expr
>) -> PResult
<P
<Expr
>> {
2740 let restrictions
= self.restrictions
& Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
;
2741 let op_span
= self.span
;
2745 let rhs
= try
!(self.parse_expr_res(restrictions
));
2746 Ok(self.mk_expr(lhs
.span
.lo
, rhs
.span
.hi
, ExprAssign(lhs
, rhs
)))
2748 token
::BinOpEq(op
) => {
2750 let rhs
= try
!(self.parse_expr_res(restrictions
));
2751 let aop
= match op
{
2752 token
::Plus
=> BiAdd
,
2753 token
::Minus
=> BiSub
,
2754 token
::Star
=> BiMul
,
2755 token
::Slash
=> BiDiv
,
2756 token
::Percent
=> BiRem
,
2757 token
::Caret
=> BiBitXor
,
2758 token
::And
=> BiBitAnd
,
2759 token
::Or
=> BiBitOr
,
2760 token
::Shl
=> BiShl
,
2763 let rhs_span
= rhs
.span
;
2764 let span
= lhs
.span
;
2765 let assign_op
= self.mk_assign_op(codemap
::respan(op_span
, aop
), lhs
, rhs
);
2766 Ok(self.mk_expr(span
.lo
, rhs_span
.hi
, assign_op
))
2768 // A range expression, either `expr..expr` or `expr..`.
2772 let opt_end
= if self.is_at_start_of_range_notation_rhs() {
2773 let end
= try
!(self.parse_binops());
2779 let lo
= lhs
.span
.lo
;
2780 let hi
= self.span
.hi
;
2781 let range
= self.mk_range(Some(lhs
), opt_end
);
2782 return Ok(self.mk_expr(lo
, hi
, range
));
2791 fn is_at_start_of_range_notation_rhs(&self) -> bool
{
2792 if self.token
.can_begin_expr() {
2793 // parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
2794 if self.token
== token
::OpenDelim(token
::Brace
) {
2795 return !self.restrictions
.contains(Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
);
2803 /// Parse an 'if' or 'if let' expression ('if' token already eaten)
2804 pub fn parse_if_expr(&mut self) -> PResult
<P
<Expr
>> {
2805 if self.check_keyword(keywords
::Let
) {
2806 return self.parse_if_let_expr();
2808 let lo
= self.last_span
.lo
;
2809 let cond
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
));
2810 let thn
= try
!(self.parse_block());
2811 let mut els
: Option
<P
<Expr
>> = None
;
2812 let mut hi
= thn
.span
.hi
;
2813 if try
!(self.eat_keyword(keywords
::Else
) ){
2814 let elexpr
= try
!(self.parse_else_expr());
2815 hi
= elexpr
.span
.hi
;
2818 Ok(self.mk_expr(lo
, hi
, ExprIf(cond
, thn
, els
)))
2821 /// Parse an 'if let' expression ('if' token already eaten)
2822 pub fn parse_if_let_expr(&mut self) -> PResult
<P
<Expr
>> {
2823 let lo
= self.last_span
.lo
;
2824 try
!(self.expect_keyword(keywords
::Let
));
2825 let pat
= try
!(self.parse_pat_nopanic());
2826 try
!(self.expect(&token
::Eq
));
2827 let expr
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
));
2828 let thn
= try
!(self.parse_block());
2829 let (hi
, els
) = if try
!(self.eat_keyword(keywords
::Else
) ){
2830 let expr
= try
!(self.parse_else_expr());
2831 (expr
.span
.hi
, Some(expr
))
2835 Ok(self.mk_expr(lo
, hi
, ExprIfLet(pat
, expr
, thn
, els
)))
2839 pub fn parse_lambda_expr(&mut self, lo
: BytePos
, capture_clause
: CaptureClause
)
2842 let decl
= try
!(self.parse_fn_block_decl());
2843 let body
= match decl
.output
{
2844 DefaultReturn(_
) => {
2845 // If no explicit return type is given, parse any
2846 // expr and wrap it up in a dummy block:
2847 let body_expr
= try
!(self.parse_expr_nopanic());
2849 id
: ast
::DUMMY_NODE_ID
,
2851 span
: body_expr
.span
,
2852 expr
: Some(body_expr
),
2853 rules
: DefaultBlock
,
2857 // If an explicit return type is given, require a
2858 // block to appear (RFC 968).
2859 try
!(self.parse_block())
2866 ExprClosure(capture_clause
, decl
, body
)))
2869 pub fn parse_else_expr(&mut self) -> PResult
<P
<Expr
>> {
2870 if try
!(self.eat_keyword(keywords
::If
) ){
2871 return self.parse_if_expr();
2873 let blk
= try
!(self.parse_block());
2874 return Ok(self.mk_expr(blk
.span
.lo
, blk
.span
.hi
, ExprBlock(blk
)));
2878 /// Parse a 'for' .. 'in' expression ('for' token already eaten)
2879 pub fn parse_for_expr(&mut self, opt_ident
: Option
<ast
::Ident
>) -> PResult
<P
<Expr
>> {
2880 // Parse: `for <src_pat> in <src_expr> <src_loop_block>`
2882 let lo
= self.last_span
.lo
;
2883 let pat
= try
!(self.parse_pat_nopanic());
2884 try
!(self.expect_keyword(keywords
::In
));
2885 let expr
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
));
2886 let loop_block
= try
!(self.parse_block());
2887 let hi
= self.last_span
.hi
;
2889 Ok(self.mk_expr(lo
, hi
, ExprForLoop(pat
, expr
, loop_block
, opt_ident
)))
2892 /// Parse a 'while' or 'while let' expression ('while' token already eaten)
2893 pub fn parse_while_expr(&mut self, opt_ident
: Option
<ast
::Ident
>) -> PResult
<P
<Expr
>> {
2894 if self.token
.is_keyword(keywords
::Let
) {
2895 return self.parse_while_let_expr(opt_ident
);
2897 let lo
= self.last_span
.lo
;
2898 let cond
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
));
2899 let body
= try
!(self.parse_block());
2900 let hi
= body
.span
.hi
;
2901 return Ok(self.mk_expr(lo
, hi
, ExprWhile(cond
, body
, opt_ident
)));
2904 /// Parse a 'while let' expression ('while' token already eaten)
2905 pub fn parse_while_let_expr(&mut self, opt_ident
: Option
<ast
::Ident
>) -> PResult
<P
<Expr
>> {
2906 let lo
= self.last_span
.lo
;
2907 try
!(self.expect_keyword(keywords
::Let
));
2908 let pat
= try
!(self.parse_pat_nopanic());
2909 try
!(self.expect(&token
::Eq
));
2910 let expr
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
));
2911 let body
= try
!(self.parse_block());
2912 let hi
= body
.span
.hi
;
2913 return Ok(self.mk_expr(lo
, hi
, ExprWhileLet(pat
, expr
, body
, opt_ident
)));
2916 pub fn parse_loop_expr(&mut self, opt_ident
: Option
<ast
::Ident
>) -> PResult
<P
<Expr
>> {
2917 let lo
= self.last_span
.lo
;
2918 let body
= try
!(self.parse_block());
2919 let hi
= body
.span
.hi
;
2920 Ok(self.mk_expr(lo
, hi
, ExprLoop(body
, opt_ident
)))
2923 fn parse_match_expr(&mut self) -> PResult
<P
<Expr
>> {
2924 let lo
= self.last_span
.lo
;
2925 let discriminant
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_NO_STRUCT_LITERAL
));
2926 try
!(self.commit_expr_expecting(&*discriminant
, token
::OpenDelim(token
::Brace
)));
2927 let mut arms
: Vec
<Arm
> = Vec
::new();
2928 while self.token
!= token
::CloseDelim(token
::Brace
) {
2929 arms
.push(try
!(self.parse_arm_nopanic()));
2931 let hi
= self.span
.hi
;
2933 return Ok(self.mk_expr(lo
, hi
, ExprMatch(discriminant
, arms
, MatchSource
::Normal
)));
2936 pub fn parse_arm_nopanic(&mut self) -> PResult
<Arm
> {
2937 maybe_whole
!(no_clone
self, NtArm
);
2939 let attrs
= self.parse_outer_attributes();
2940 let pats
= try
!(self.parse_pats());
2941 let mut guard
= None
;
2942 if try
!(self.eat_keyword(keywords
::If
) ){
2943 guard
= Some(try
!(self.parse_expr_nopanic()));
2945 try
!(self.expect(&token
::FatArrow
));
2946 let expr
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_STMT_EXPR
));
2949 !classify
::expr_is_simple_block(&*expr
)
2950 && self.token
!= token
::CloseDelim(token
::Brace
);
2953 try
!(self.commit_expr(&*expr
, &[token
::Comma
], &[token
::CloseDelim(token
::Brace
)]));
2955 try
!(self.eat(&token
::Comma
));
2966 /// Parse an expression
2967 pub fn parse_expr_nopanic(&mut self) -> PResult
<P
<Expr
>> {
2968 self.parse_expr_res(Restrictions
::empty())
2971 /// Parse an expression, subject to the given restrictions
2972 pub fn parse_expr_res(&mut self, r
: Restrictions
) -> PResult
<P
<Expr
>> {
2973 let old
= self.restrictions
;
2974 self.restrictions
= r
;
2975 let e
= try
!(self.parse_assign_expr());
2976 self.restrictions
= old
;
2980 /// Parse the RHS of a local variable declaration (e.g. '= 14;')
2981 fn parse_initializer(&mut self) -> PResult
<Option
<P
<Expr
>>> {
2982 if self.check(&token
::Eq
) {
2984 Ok(Some(try
!(self.parse_expr_nopanic())))
2990 /// Parse patterns, separated by '|' s
2991 fn parse_pats(&mut self) -> PResult
<Vec
<P
<Pat
>>> {
2992 let mut pats
= Vec
::new();
2994 pats
.push(try
!(self.parse_pat_nopanic()));
2995 if self.check(&token
::BinOp(token
::Or
)) { try!(self.bump());}
2996 else { return Ok(pats); }
3000 fn parse_pat_tuple_elements(&mut self) -> PResult
<Vec
<P
<Pat
>>> {
3001 let mut fields
= vec
![];
3002 if !self.check(&token
::CloseDelim(token
::Paren
)) {
3003 fields
.push(try
!(self.parse_pat_nopanic()));
3004 if self.look_ahead(1, |t
| *t
!= token
::CloseDelim(token
::Paren
)) {
3005 while try
!(self.eat(&token
::Comma
)) &&
3006 !self.check(&token
::CloseDelim(token
::Paren
)) {
3007 fields
.push(try
!(self.parse_pat_nopanic()));
3010 if fields
.len() == 1 {
3011 try
!(self.expect(&token
::Comma
));
3017 fn parse_pat_vec_elements(
3019 ) -> PResult
<(Vec
<P
<Pat
>>, Option
<P
<Pat
>>, Vec
<P
<Pat
>>)> {
3020 let mut before
= Vec
::new();
3021 let mut slice
= None
;
3022 let mut after
= Vec
::new();
3023 let mut first
= true;
3024 let mut before_slice
= true;
3026 while self.token
!= token
::CloseDelim(token
::Bracket
) {
3030 try
!(self.expect(&token
::Comma
));
3032 if self.token
== token
::CloseDelim(token
::Bracket
)
3033 && (before_slice
|| !after
.is_empty()) {
3039 if self.check(&token
::DotDot
) {
3042 if self.check(&token
::Comma
) ||
3043 self.check(&token
::CloseDelim(token
::Bracket
)) {
3044 slice
= Some(P(ast
::Pat
{
3045 id
: ast
::DUMMY_NODE_ID
,
3046 node
: PatWild(PatWildMulti
),
3049 before_slice
= false;
3055 let subpat
= try
!(self.parse_pat_nopanic());
3056 if before_slice
&& self.check(&token
::DotDot
) {
3058 slice
= Some(subpat
);
3059 before_slice
= false;
3060 } else if before_slice
{
3061 before
.push(subpat
);
3067 Ok((before
, slice
, after
))
3070 /// Parse the fields of a struct-like pattern
3071 fn parse_pat_fields(&mut self) -> PResult
<(Vec
<codemap
::Spanned
<ast
::FieldPat
>> , bool
)> {
3072 let mut fields
= Vec
::new();
3073 let mut etc
= false;
3074 let mut first
= true;
3075 while self.token
!= token
::CloseDelim(token
::Brace
) {
3079 try
!(self.expect(&token
::Comma
));
3080 // accept trailing commas
3081 if self.check(&token
::CloseDelim(token
::Brace
)) { break }
3084 let lo
= self.span
.lo
;
3087 if self.check(&token
::DotDot
) {
3089 if self.token
!= token
::CloseDelim(token
::Brace
) {
3090 let token_str
= self.this_token_to_string();
3091 return Err(self.fatal(&format
!("expected `{}`, found `{}`", "}",
3098 // Check if a colon exists one ahead. This means we're parsing a fieldname.
3099 let (subpat
, fieldname
, is_shorthand
) = if self.look_ahead(1, |t
| t
== &token
::Colon
) {
3100 // Parsing a pattern of the form "fieldname: pat"
3101 let fieldname
= try
!(self.parse_ident());
3103 let pat
= try
!(self.parse_pat_nopanic());
3105 (pat
, fieldname
, false)
3107 // Parsing a pattern of the form "(box) (ref) (mut) fieldname"
3108 let is_box
= try
!(self.eat_keyword(keywords
::Box
));
3109 let boxed_span_lo
= self.span
.lo
;
3110 let is_ref
= try
!(self.eat_keyword(keywords
::Ref
));
3111 let is_mut
= try
!(self.eat_keyword(keywords
::Mut
));
3112 let fieldname
= try
!(self.parse_ident());
3113 hi
= self.last_span
.hi
;
3115 let bind_type
= match (is_ref
, is_mut
) {
3116 (true, true) => BindByRef(MutMutable
),
3117 (true, false) => BindByRef(MutImmutable
),
3118 (false, true) => BindByValue(MutMutable
),
3119 (false, false) => BindByValue(MutImmutable
),
3121 let fieldpath
= codemap
::Spanned{span:self.last_span, node:fieldname}
;
3122 let fieldpat
= P(ast
::Pat
{
3123 id
: ast
::DUMMY_NODE_ID
,
3124 node
: PatIdent(bind_type
, fieldpath
, None
),
3125 span
: mk_sp(boxed_span_lo
, hi
),
3128 let subpat
= if is_box
{
3130 id
: ast
::DUMMY_NODE_ID
,
3131 node
: PatBox(fieldpat
),
3132 span
: mk_sp(lo
, hi
),
3137 (subpat
, fieldname
, true)
3140 fields
.push(codemap
::Spanned
{ span
: mk_sp(lo
, hi
),
3141 node
: ast
::FieldPat
{ ident
: fieldname
,
3143 is_shorthand
: is_shorthand
}});
3145 return Ok((fields
, etc
));
3148 fn parse_pat_range_end(&mut self) -> PResult
<P
<Expr
>> {
3149 if self.is_path_start() {
3150 let lo
= self.span
.lo
;
3151 let (qself
, path
) = if try
!(self.eat_lt()) {
3152 // Parse a qualified path
3154 try
!(self.parse_qualified_path(NoTypesAllowed
));
3157 // Parse an unqualified path
3158 (None
, try
!(self.parse_path(LifetimeAndTypesWithColons
)))
3160 let hi
= self.last_span
.hi
;
3161 Ok(self.mk_expr(lo
, hi
, ExprPath(qself
, path
)))
3163 self.parse_literal_maybe_minus()
3167 fn is_path_start(&self) -> bool
{
3168 (self.token
== token
::Lt
|| self.token
== token
::ModSep
3169 || self.token
.is_ident() || self.token
.is_path())
3170 && !self.token
.is_keyword(keywords
::True
) && !self.token
.is_keyword(keywords
::False
)
3173 /// Parse a pattern.
3174 pub fn parse_pat_nopanic(&mut self) -> PResult
<P
<Pat
>> {
3175 maybe_whole
!(self, NtPat
);
3177 let lo
= self.span
.lo
;
3180 token
::Underscore
=> {
3183 pat
= PatWild(PatWildSingle
);
3185 token
::BinOp(token
::And
) | token
::AndAnd
=> {
3186 // Parse &pat / &mut pat
3187 try
!(self.expect_and());
3188 let mutbl
= try
!(self.parse_mutability());
3189 let subpat
= try
!(self.parse_pat_nopanic());
3190 pat
= PatRegion(subpat
, mutbl
);
3192 token
::OpenDelim(token
::Paren
) => {
3193 // Parse (pat,pat,pat,...) as tuple pattern
3195 let fields
= try
!(self.parse_pat_tuple_elements());
3196 try
!(self.expect(&token
::CloseDelim(token
::Paren
)));
3197 pat
= PatTup(fields
);
3199 token
::OpenDelim(token
::Bracket
) => {
3200 // Parse [pat,pat,...] as vector pattern
3202 let (before
, slice
, after
) = try
!(self.parse_pat_vec_elements());
3203 try
!(self.expect(&token
::CloseDelim(token
::Bracket
)));
3204 pat
= PatVec(before
, slice
, after
);
3207 // At this point, token != _, &, &&, (, [
3208 if try
!(self.eat_keyword(keywords
::Mut
)) {
3209 // Parse mut ident @ pat
3210 pat
= try
!(self.parse_pat_ident(BindByValue(MutMutable
)));
3211 } else if try
!(self.eat_keyword(keywords
::Ref
)) {
3212 // Parse ref ident @ pat / ref mut ident @ pat
3213 let mutbl
= try
!(self.parse_mutability());
3214 pat
= try
!(self.parse_pat_ident(BindByRef(mutbl
)));
3215 } else if try
!(self.eat_keyword(keywords
::Box
)) {
3217 let subpat
= try
!(self.parse_pat_nopanic());
3218 pat
= PatBox(subpat
);
3219 } else if self.is_path_start() {
3220 // Parse pattern starting with a path
3221 if self.token
.is_plain_ident() && self.look_ahead(1, |t
| *t
!= token
::DotDotDot
&&
3222 *t
!= token
::OpenDelim(token
::Brace
) &&
3223 *t
!= token
::OpenDelim(token
::Paren
) &&
3224 // Contrary to its definition, a plain ident can be followed by :: in macros
3225 *t
!= token
::ModSep
) {
3226 // Plain idents have some extra abilities here compared to general paths
3227 if self.look_ahead(1, |t
| *t
== token
::Not
) {
3228 // Parse macro invocation
3229 let ident
= try
!(self.parse_ident());
3230 let ident_span
= self.last_span
;
3231 let path
= ident_to_path(ident_span
, ident
);
3233 let delim
= try
!(self.expect_open_delim());
3234 let tts
= try
!(self.parse_seq_to_end(&token
::CloseDelim(delim
),
3235 seq_sep_none(), |p
| p
.parse_token_tree()));
3236 let mac
= MacInvocTT(path
, tts
, EMPTY_CTXT
);
3237 pat
= PatMac(codemap
::Spanned {node: mac, span: self.span}
);
3239 // Parse ident @ pat
3240 // This can give false positives and parse nullary enums,
3241 // they are dealt with later in resolve
3242 pat
= try
!(self.parse_pat_ident(BindByValue(MutImmutable
)));
3245 let (qself
, path
) = if try
!(self.eat_lt()) {
3246 // Parse a qualified path
3248 try
!(self.parse_qualified_path(NoTypesAllowed
));
3251 // Parse an unqualified path
3252 (None
, try
!(self.parse_path(LifetimeAndTypesWithColons
)))
3255 token
::DotDotDot
=> {
3257 let hi
= self.last_span
.hi
;
3258 let begin
= self.mk_expr(lo
, hi
, ExprPath(qself
, path
));
3260 let end
= try
!(self.parse_pat_range_end());
3261 pat
= PatRange(begin
, end
);
3263 token
::OpenDelim(token
::Brace
) => {
3264 if qself
.is_some() {
3265 let span
= self.span
;
3267 "unexpected `{` after qualified path");
3268 self.abort_if_errors();
3270 // Parse struct pattern
3272 let (fields
, etc
) = try
!(self.parse_pat_fields());
3274 pat
= PatStruct(path
, fields
, etc
);
3276 token
::OpenDelim(token
::Paren
) => {
3277 if qself
.is_some() {
3278 let span
= self.span
;
3280 "unexpected `(` after qualified path");
3281 self.abort_if_errors();
3283 // Parse tuple struct or enum pattern
3284 if self.look_ahead(1, |t
| *t
== token
::DotDot
) {
3285 // This is a "top constructor only" pat
3288 try
!(self.expect(&token
::CloseDelim(token
::Paren
)));
3289 pat
= PatEnum(path
, None
);
3291 let args
= try
!(self.parse_enum_variant_seq(
3292 &token
::OpenDelim(token
::Paren
),
3293 &token
::CloseDelim(token
::Paren
),
3294 seq_sep_trailing_allowed(token
::Comma
),
3295 |p
| p
.parse_pat_nopanic()));
3296 pat
= PatEnum(path
, Some(args
));
3299 _
if qself
.is_some() => {
3300 // Parse qualified path
3301 pat
= PatQPath(qself
.unwrap(), path
);
3304 // Parse nullary enum
3305 pat
= PatEnum(path
, Some(vec
![]));
3310 // Try to parse everything else as literal with optional minus
3311 let begin
= try
!(self.parse_literal_maybe_minus());
3312 if try
!(self.eat(&token
::DotDotDot
)) {
3313 let end
= try
!(self.parse_pat_range_end());
3314 pat
= PatRange(begin
, end
);
3316 pat
= PatLit(begin
);
3322 let hi
= self.last_span
.hi
;
3324 id
: ast
::DUMMY_NODE_ID
,
3326 span
: mk_sp(lo
, hi
),
3330 /// Parse ident or ident @ pat
3331 /// used by the copy foo and ref foo patterns to give a good
3332 /// error message when parsing mistakes like ref foo(a,b)
3333 fn parse_pat_ident(&mut self,
3334 binding_mode
: ast
::BindingMode
)
3335 -> PResult
<ast
::Pat_
> {
3336 if !self.token
.is_plain_ident() {
3337 let span
= self.span
;
3338 let tok_str
= self.this_token_to_string();
3339 return Err(self.span_fatal(span
,
3340 &format
!("expected identifier, found `{}`", tok_str
)))
3342 let ident
= try
!(self.parse_ident());
3343 let last_span
= self.last_span
;
3344 let name
= codemap
::Spanned{span: last_span, node: ident}
;
3345 let sub
= if try
!(self.eat(&token
::At
) ){
3346 Some(try
!(self.parse_pat_nopanic()))
3351 // just to be friendly, if they write something like
3353 // we end up here with ( as the current token. This shortly
3354 // leads to a parse error. Note that if there is no explicit
3355 // binding mode then we do not end up here, because the lookahead
3356 // will direct us over to parse_enum_variant()
3357 if self.token
== token
::OpenDelim(token
::Paren
) {
3358 let last_span
= self.last_span
;
3359 return Err(self.span_fatal(
3361 "expected identifier, found enum pattern"))
3364 Ok(PatIdent(binding_mode
, name
, sub
))
3367 /// Parse a local variable declaration
3368 fn parse_local(&mut self) -> PResult
<P
<Local
>> {
3369 let lo
= self.span
.lo
;
3370 let pat
= try
!(self.parse_pat_nopanic());
3373 if try
!(self.eat(&token
::Colon
) ){
3374 ty
= Some(try
!(self.parse_ty_sum()));
3376 let init
= try
!(self.parse_initializer());
3381 id
: ast
::DUMMY_NODE_ID
,
3382 span
: mk_sp(lo
, self.last_span
.hi
),
3387 /// Parse a "let" stmt
3388 fn parse_let(&mut self) -> PResult
<P
<Decl
>> {
3389 let lo
= self.span
.lo
;
3390 let local
= try
!(self.parse_local());
3391 Ok(P(spanned(lo
, self.last_span
.hi
, DeclLocal(local
))))
3394 /// Parse a structure field
3395 fn parse_name_and_ty(&mut self, pr
: Visibility
,
3396 attrs
: Vec
<Attribute
> ) -> PResult
<StructField
> {
3398 Inherited
=> self.span
.lo
,
3399 Public
=> self.last_span
.lo
,
3401 if !self.token
.is_plain_ident() {
3402 return Err(self.fatal("expected ident"));
3404 let name
= try
!(self.parse_ident());
3405 try
!(self.expect(&token
::Colon
));
3406 let ty
= try
!(self.parse_ty_sum());
3407 Ok(spanned(lo
, self.last_span
.hi
, ast
::StructField_
{
3408 kind
: NamedField(name
, pr
),
3409 id
: ast
::DUMMY_NODE_ID
,
3415 /// Emit an expected item after attributes error.
3416 fn expected_item_err(&self, attrs
: &[Attribute
]) {
3417 let message
= match attrs
.last() {
3418 Some(&Attribute { node: ast::Attribute_ { is_sugared_doc: true, .. }
, .. }) => {
3419 "expected item after doc comment"
3421 _
=> "expected item after attributes",
3424 self.span_err(self.last_span
, message
);
3427 /// Parse a statement. may include decl.
3428 pub fn parse_stmt_nopanic(&mut self) -> PResult
<Option
<P
<Stmt
>>> {
3429 Ok(try
!(self.parse_stmt_()).map(P
))
3432 fn parse_stmt_(&mut self) -> PResult
<Option
<Stmt
>> {
3433 maybe_whole
!(Some deref
self, NtStmt
);
3435 fn check_expected_item(p
: &mut Parser
, attrs
: &[Attribute
]) {
3436 // If we have attributes then we should have an item
3437 if !attrs
.is_empty() {
3438 p
.expected_item_err(attrs
);
3442 let attrs
= self.parse_outer_attributes();
3443 let lo
= self.span
.lo
;
3445 Ok(Some(if self.check_keyword(keywords
::Let
) {
3446 check_expected_item(self, &attrs
);
3447 try
!(self.expect_keyword(keywords
::Let
));
3448 let decl
= try
!(self.parse_let());
3449 spanned(lo
, decl
.span
.hi
, StmtDecl(decl
, ast
::DUMMY_NODE_ID
))
3450 } else if self.token
.is_ident()
3451 && !self.token
.is_any_keyword()
3452 && self.look_ahead(1, |t
| *t
== token
::Not
) {
3453 // it's a macro invocation:
3455 check_expected_item(self, &attrs
);
3457 // Potential trouble: if we allow macros with paths instead of
3458 // idents, we'd need to look ahead past the whole path here...
3459 let pth
= try
!(self.parse_path(NoTypesAllowed
));
3462 let id
= match self.token
{
3463 token
::OpenDelim(_
) => token
::special_idents
::invalid
, // no special identifier
3464 _
=> try
!(self.parse_ident()),
3467 // check that we're pointing at delimiters (need to check
3468 // again after the `if`, because of `parse_ident`
3469 // consuming more tokens).
3470 let delim
= match self.token
{
3471 token
::OpenDelim(delim
) => delim
,
3473 // we only expect an ident if we didn't parse one
3475 let ident_str
= if id
.name
== token
::special_idents
::invalid
.name
{
3480 let tok_str
= self.this_token_to_string();
3481 return Err(self.fatal(&format
!("expected {}`(` or `{{`, found `{}`",
3487 let tts
= try
!(self.parse_unspanned_seq(
3488 &token
::OpenDelim(delim
),
3489 &token
::CloseDelim(delim
),
3491 |p
| p
.parse_token_tree()
3493 let hi
= self.last_span
.hi
;
3495 let style
= if delim
== token
::Brace
{
3498 MacStmtWithoutBraces
3501 if id
.name
== token
::special_idents
::invalid
.name
{
3503 StmtMac(P(spanned(lo
,
3505 MacInvocTT(pth
, tts
, EMPTY_CTXT
))),
3508 // if it has a special ident, it's definitely an item
3510 // Require a semicolon or braces.
3511 if style
!= MacStmtWithBraces
{
3512 if !try
!(self.eat(&token
::Semi
) ){
3513 let last_span
= self.last_span
;
3514 self.span_err(last_span
,
3515 "macros that expand to items must \
3516 either be surrounded with braces or \
3517 followed by a semicolon");
3520 spanned(lo
, hi
, StmtDecl(
3521 P(spanned(lo
, hi
, DeclItem(
3523 lo
, hi
, id
/*id is good here*/,
3524 ItemMac(spanned(lo
, hi
, MacInvocTT(pth
, tts
, EMPTY_CTXT
))),
3525 Inherited
, Vec
::new(/*no attrs*/))))),
3526 ast
::DUMMY_NODE_ID
))
3529 match try
!(self.parse_item_(attrs
, false)) {
3532 let decl
= P(spanned(lo
, hi
, DeclItem(i
)));
3533 spanned(lo
, hi
, StmtDecl(decl
, ast
::DUMMY_NODE_ID
))
3536 // Do not attempt to parse an expression if we're done here.
3537 if self.token
== token
::Semi
{
3542 if self.token
== token
::CloseDelim(token
::Brace
) {
3546 // Remainder are line-expr stmts.
3547 let e
= try
!(self.parse_expr_res(Restrictions
::RESTRICTION_STMT_EXPR
));
3548 spanned(lo
, e
.span
.hi
, StmtExpr(e
, ast
::DUMMY_NODE_ID
))
3554 /// Is this expression a successfully-parsed statement?
3555 fn expr_is_complete(&mut self, e
: &Expr
) -> bool
{
3556 self.restrictions
.contains(Restrictions
::RESTRICTION_STMT_EXPR
) &&
3557 !classify
::expr_requires_semi_to_be_stmt(e
)
3560 /// Parse a block. No inner attrs are allowed.
3561 pub fn parse_block(&mut self) -> PResult
<P
<Block
>> {
3562 maybe_whole
!(no_clone
self, NtBlock
);
3564 let lo
= self.span
.lo
;
3566 if !try
!(self.eat(&token
::OpenDelim(token
::Brace
)) ){
3568 let tok
= self.this_token_to_string();
3569 return Err(self.span_fatal_help(sp
,
3570 &format
!("expected `{{`, found `{}`", tok
),
3571 "place this code inside a block"));
3574 self.parse_block_tail(lo
, DefaultBlock
)
3577 /// Parse a block. Inner attrs are allowed.
3578 fn parse_inner_attrs_and_block(&mut self) -> PResult
<(Vec
<Attribute
>, P
<Block
>)> {
3579 maybe_whole
!(pair_empty
self, NtBlock
);
3581 let lo
= self.span
.lo
;
3582 try
!(self.expect(&token
::OpenDelim(token
::Brace
)));
3583 Ok((self.parse_inner_attributes(),
3584 try
!(self.parse_block_tail(lo
, DefaultBlock
))))
3587 /// Parse the rest of a block expression or function body
3588 /// Precondition: already parsed the '{'.
3589 fn parse_block_tail(&mut self, lo
: BytePos
, s
: BlockCheckMode
) -> PResult
<P
<Block
>> {
3590 let mut stmts
= vec
![];
3591 let mut expr
= None
;
3593 while !try
!(self.eat(&token
::CloseDelim(token
::Brace
))) {
3594 let Spanned {node, span}
= if let Some(s
) = try
!(self.parse_stmt_()) {
3597 // Found only `;` or `}`.
3602 try
!(self.handle_expression_like_statement(e
, span
, &mut stmts
, &mut expr
));
3604 StmtMac(mac
, MacStmtWithoutBraces
) => {
3605 // statement macro without braces; might be an
3606 // expr depending on whether a semicolon follows
3609 stmts
.push(P(Spanned
{
3610 node
: StmtMac(mac
, MacStmtWithSemicolon
),
3611 span
: mk_sp(span
.lo
, self.span
.hi
),
3616 let e
= self.mk_mac_expr(span
.lo
, span
.hi
,
3617 mac
.and_then(|m
| m
.node
));
3618 let e
= try
!(self.parse_dot_or_call_expr_with(e
));
3619 let e
= try
!(self.parse_more_binops(e
, 0));
3620 let e
= try
!(self.parse_assign_expr_with(e
));
3621 try
!(self.handle_expression_like_statement(
3629 StmtMac(m
, style
) => {
3630 // statement macro; might be an expr
3633 stmts
.push(P(Spanned
{
3634 node
: StmtMac(m
, MacStmtWithSemicolon
),
3635 span
: mk_sp(span
.lo
, self.span
.hi
),
3639 token
::CloseDelim(token
::Brace
) => {
3640 // if a block ends in `m!(arg)` without
3641 // a `;`, it must be an expr
3642 expr
= Some(self.mk_mac_expr(span
.lo
, span
.hi
,
3643 m
.and_then(|x
| x
.node
)));
3646 stmts
.push(P(Spanned
{
3647 node
: StmtMac(m
, style
),
3653 _
=> { // all other kinds of statements:
3654 let mut hi
= span
.hi
;
3655 if classify
::stmt_ends_with_semi(&node
) {
3656 try
!(self.commit_stmt_expecting(token
::Semi
));
3657 hi
= self.last_span
.hi
;
3660 stmts
.push(P(Spanned
{
3662 span
: mk_sp(span
.lo
, hi
)
3671 id
: ast
::DUMMY_NODE_ID
,
3673 span
: mk_sp(lo
, self.last_span
.hi
),
3677 fn handle_expression_like_statement(
3681 stmts
: &mut Vec
<P
<Stmt
>>,
3682 last_block_expr
: &mut Option
<P
<Expr
>>) -> PResult
<()> {
3683 // expression without semicolon
3684 if classify
::expr_requires_semi_to_be_stmt(&*e
) {
3685 // Just check for errors and recover; do not eat semicolon yet.
3686 try
!(self.commit_stmt(&[],
3687 &[token
::Semi
, token
::CloseDelim(token
::Brace
)]));
3693 let span_with_semi
= Span
{
3695 hi
: self.last_span
.hi
,
3696 expn_id
: span
.expn_id
,
3698 stmts
.push(P(Spanned
{
3699 node
: StmtSemi(e
, ast
::DUMMY_NODE_ID
),
3700 span
: span_with_semi
,
3703 token
::CloseDelim(token
::Brace
) => *last_block_expr
= Some(e
),
3705 stmts
.push(P(Spanned
{
3706 node
: StmtExpr(e
, ast
::DUMMY_NODE_ID
),
3714 // Parses a sequence of bounds if a `:` is found,
3715 // otherwise returns empty list.
3716 fn parse_colon_then_ty_param_bounds(&mut self,
3717 mode
: BoundParsingMode
)
3718 -> PResult
<OwnedSlice
<TyParamBound
>>
3720 if !try
!(self.eat(&token
::Colon
) ){
3721 Ok(OwnedSlice
::empty())
3723 self.parse_ty_param_bounds(mode
)
3727 // matches bounds = ( boundseq )?
3728 // where boundseq = ( polybound + boundseq ) | polybound
3729 // and polybound = ( 'for' '<' 'region '>' )? bound
3730 // and bound = 'region | trait_ref
3731 fn parse_ty_param_bounds(&mut self,
3732 mode
: BoundParsingMode
)
3733 -> PResult
<OwnedSlice
<TyParamBound
>>
3735 let mut result
= vec
!();
3737 let question_span
= self.span
;
3738 let ate_question
= try
!(self.eat(&token
::Question
));
3740 token
::Lifetime(lifetime
) => {
3742 self.span_err(question_span
,
3743 "`?` may only modify trait bounds, not lifetime bounds");
3745 result
.push(RegionTyParamBound(ast
::Lifetime
{
3746 id
: ast
::DUMMY_NODE_ID
,
3752 token
::ModSep
| token
::Ident(..) => {
3753 let poly_trait_ref
= try
!(self.parse_poly_trait_ref());
3754 let modifier
= if ate_question
{
3755 if mode
== BoundParsingMode
::Modified
{
3756 TraitBoundModifier
::Maybe
3758 self.span_err(question_span
,
3760 TraitBoundModifier
::None
3763 TraitBoundModifier
::None
3765 result
.push(TraitTyParamBound(poly_trait_ref
, modifier
))
3770 if !try
!(self.eat(&token
::BinOp(token
::Plus
)) ){
3775 return Ok(OwnedSlice
::from_vec(result
));
3778 /// Matches typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?
3779 fn parse_ty_param(&mut self) -> PResult
<TyParam
> {
3780 let span
= self.span
;
3781 let ident
= try
!(self.parse_ident());
3783 let bounds
= try
!(self.parse_colon_then_ty_param_bounds(BoundParsingMode
::Modified
));
3785 let default = if self.check(&token
::Eq
) {
3787 Some(try
!(self.parse_ty_sum()))
3794 id
: ast
::DUMMY_NODE_ID
,
3801 /// Parse a set of optional generic type parameter declarations. Where
3802 /// clauses are not parsed here, and must be added later via
3803 /// `parse_where_clause()`.
3805 /// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
3806 /// | ( < lifetimes , typaramseq ( , )? > )
3807 /// where typaramseq = ( typaram ) | ( typaram , typaramseq )
3808 pub fn parse_generics(&mut self) -> PResult
<ast
::Generics
> {
3809 maybe_whole
!(self, NtGenerics
);
3811 if try
!(self.eat(&token
::Lt
) ){
3812 let lifetime_defs
= try
!(self.parse_lifetime_defs());
3813 let mut seen_default
= false;
3814 let ty_params
= try
!(self.parse_seq_to_gt(Some(token
::Comma
), |p
| {
3815 try
!(p
.forbid_lifetime());
3816 let ty_param
= try
!(p
.parse_ty_param());
3817 if ty_param
.default.is_some() {
3818 seen_default
= true;
3819 } else if seen_default
{
3820 let last_span
= p
.last_span
;
3821 p
.span_err(last_span
,
3822 "type parameters with a default must be trailing");
3827 lifetimes
: lifetime_defs
,
3828 ty_params
: ty_params
,
3829 where_clause
: WhereClause
{
3830 id
: ast
::DUMMY_NODE_ID
,
3831 predicates
: Vec
::new(),
3835 Ok(ast_util
::empty_generics())
3839 fn parse_generic_values_after_lt(&mut self) -> PResult
<(Vec
<ast
::Lifetime
>,
3841 Vec
<P
<TypeBinding
>>)> {
3842 let span_lo
= self.span
.lo
;
3843 let lifetimes
= try
!(self.parse_lifetimes(token
::Comma
));
3845 let missing_comma
= !lifetimes
.is_empty() &&
3846 !self.token
.is_like_gt() &&
3848 .as_ref().map_or(true,
3849 |x
| &**x
!= &token
::Comma
);
3853 let msg
= format
!("expected `,` or `>` after lifetime \
3855 self.this_token_to_string());
3856 self.span_err(self.span
, &msg
);
3858 let span_hi
= self.span
.hi
;
3859 let span_hi
= if self.parse_ty_nopanic().is_ok() {
3865 let msg
= format
!("did you mean a single argument type &'a Type, \
3866 or did you mean the comma-separated arguments \
3868 self.span_note(mk_sp(span_lo
, span_hi
), &msg
);
3870 self.abort_if_errors()
3873 // First parse types.
3874 let (types
, returned
) = try
!(self.parse_seq_to_gt_or_return(
3877 try
!(p
.forbid_lifetime());
3878 if p
.look_ahead(1, |t
| t
== &token
::Eq
) {
3881 Ok(Some(try
!(p
.parse_ty_sum())))
3886 // If we found the `>`, don't continue.
3888 return Ok((lifetimes
, types
.into_vec(), Vec
::new()));
3891 // Then parse type bindings.
3892 let bindings
= try
!(self.parse_seq_to_gt(
3895 try
!(p
.forbid_lifetime());
3897 let ident
= try
!(p
.parse_ident());
3898 let found_eq
= try
!(p
.eat(&token
::Eq
));
3901 p
.span_warn(span
, "whoops, no =?");
3903 let ty
= try
!(p
.parse_ty_nopanic());
3905 let span
= mk_sp(lo
, hi
);
3906 return Ok(P(TypeBinding
{id
: ast
::DUMMY_NODE_ID
,
3913 Ok((lifetimes
, types
.into_vec(), bindings
.into_vec()))
3916 fn forbid_lifetime(&mut self) -> PResult
<()> {
3917 if self.token
.is_lifetime() {
3918 let span
= self.span
;
3919 return Err(self.span_fatal(span
, "lifetime parameters must be declared \
3920 prior to type parameters"))
3925 /// Parses an optional `where` clause and places it in `generics`.
3928 /// where T : Trait<U, V> + 'b, 'a : 'b
3930 pub fn parse_where_clause(&mut self) -> PResult
<ast
::WhereClause
> {
3931 maybe_whole
!(self, NtWhereClause
);
3933 let mut where_clause
= WhereClause
{
3934 id
: ast
::DUMMY_NODE_ID
,
3935 predicates
: Vec
::new(),
3938 if !try
!(self.eat_keyword(keywords
::Where
)) {
3939 return Ok(where_clause
);
3942 let mut parsed_something
= false;
3944 let lo
= self.span
.lo
;
3946 token
::OpenDelim(token
::Brace
) => {
3950 token
::Lifetime(..) => {
3951 let bounded_lifetime
=
3952 try
!(self.parse_lifetime());
3954 try
!(self.eat(&token
::Colon
));
3957 try
!(self.parse_lifetimes(token
::BinOp(token
::Plus
)));
3959 let hi
= self.last_span
.hi
;
3960 let span
= mk_sp(lo
, hi
);
3962 where_clause
.predicates
.push(ast
::WherePredicate
::RegionPredicate(
3963 ast
::WhereRegionPredicate
{
3965 lifetime
: bounded_lifetime
,
3970 parsed_something
= true;
3974 let bound_lifetimes
= if try
!(self.eat_keyword(keywords
::For
) ){
3975 // Higher ranked constraint.
3976 try
!(self.expect(&token
::Lt
));
3977 let lifetime_defs
= try
!(self.parse_lifetime_defs());
3978 try
!(self.expect_gt());
3984 let bounded_ty
= try
!(self.parse_ty_nopanic());
3986 if try
!(self.eat(&token
::Colon
) ){
3987 let bounds
= try
!(self.parse_ty_param_bounds(BoundParsingMode
::Bare
));
3988 let hi
= self.last_span
.hi
;
3989 let span
= mk_sp(lo
, hi
);
3991 if bounds
.is_empty() {
3993 "each predicate in a `where` clause must have \
3994 at least one bound in it");
3997 where_clause
.predicates
.push(ast
::WherePredicate
::BoundPredicate(
3998 ast
::WhereBoundPredicate
{
4000 bound_lifetimes
: bound_lifetimes
,
4001 bounded_ty
: bounded_ty
,
4005 parsed_something
= true;
4006 } else if try
!(self.eat(&token
::Eq
) ){
4007 // let ty = try!(self.parse_ty_nopanic());
4008 let hi
= self.last_span
.hi
;
4009 let span
= mk_sp(lo
, hi
);
4010 // where_clause.predicates.push(
4011 // ast::WherePredicate::EqPredicate(ast::WhereEqPredicate {
4012 // id: ast::DUMMY_NODE_ID,
4014 // path: panic!("NYI"), //bounded_ty,
4017 // parsed_something = true;
4020 "equality constraints are not yet supported \
4021 in where clauses (#20041)");
4023 let last_span
= self.last_span
;
4024 self.span_err(last_span
,
4025 "unexpected token in `where` clause");
4030 if !try
!(self.eat(&token
::Comma
) ){
4035 if !parsed_something
{
4036 let last_span
= self.last_span
;
4037 self.span_err(last_span
,
4038 "a `where` clause must have at least one predicate \
4045 fn parse_fn_args(&mut self, named_args
: bool
, allow_variadic
: bool
)
4046 -> PResult
<(Vec
<Arg
> , bool
)> {
4048 let mut args
: Vec
<Option
<Arg
>> =
4049 try
!(self.parse_unspanned_seq(
4050 &token
::OpenDelim(token
::Paren
),
4051 &token
::CloseDelim(token
::Paren
),
4052 seq_sep_trailing_allowed(token
::Comma
),
4054 if p
.token
== token
::DotDotDot
{
4057 if p
.token
!= token
::CloseDelim(token
::Paren
) {
4059 return Err(p
.span_fatal(span
,
4060 "`...` must be last in argument list for variadic function"))
4064 return Err(p
.span_fatal(span
,
4065 "only foreign functions are allowed to be variadic"))
4069 Ok(Some(try
!(p
.parse_arg_general(named_args
))))
4074 let variadic
= match args
.pop() {
4077 // Need to put back that last arg
4084 if variadic
&& args
.is_empty() {
4086 "variadic function must be declared with at least one named argument");
4089 let args
= args
.into_iter().map(|x
| x
.unwrap()).collect();
4091 Ok((args
, variadic
))
4094 /// Parse the argument list and result type of a function declaration
4095 pub fn parse_fn_decl(&mut self, allow_variadic
: bool
) -> PResult
<P
<FnDecl
>> {
4097 let (args
, variadic
) = try
!(self.parse_fn_args(true, allow_variadic
));
4098 let ret_ty
= try
!(self.parse_ret_ty());
4107 fn is_self_ident(&mut self) -> bool
{
4109 token
::Ident(id
, token
::Plain
) => id
.name
== special_idents
::self_
.name
,
4114 fn expect_self_ident(&mut self) -> PResult
<ast
::Ident
> {
4116 token
::Ident(id
, token
::Plain
) if id
.name
== special_idents
::self_
.name
=> {
4121 let token_str
= self.this_token_to_string();
4122 return Err(self.fatal(&format
!("expected `self`, found `{}`",
4128 fn is_self_type_ident(&mut self) -> bool
{
4130 token
::Ident(id
, token
::Plain
) => id
.name
== special_idents
::type_self
.name
,
4135 fn expect_self_type_ident(&mut self) -> PResult
<ast
::Ident
> {
4137 token
::Ident(id
, token
::Plain
) if id
.name
== special_idents
::type_self
.name
=> {
4142 let token_str
= self.this_token_to_string();
4143 Err(self.fatal(&format
!("expected `Self`, found `{}`",
4149 /// Parse the argument list and result type of a function
4150 /// that may have a self type.
4151 fn parse_fn_decl_with_self
<F
>(&mut self,
4152 parse_arg_fn
: F
) -> PResult
<(ExplicitSelf
, P
<FnDecl
>)> where
4153 F
: FnMut(&mut Parser
) -> PResult
<Arg
>,
4155 fn maybe_parse_borrowed_explicit_self(this
: &mut Parser
)
4156 -> PResult
<ast
::ExplicitSelf_
> {
4157 // The following things are possible to see here:
4162 // fn(&'lt mut self)
4164 // We already know that the current token is `&`.
4166 if this
.look_ahead(1, |t
| t
.is_keyword(keywords
::SelfValue
)) {
4168 Ok(SelfRegion(None
, MutImmutable
, try
!(this
.expect_self_ident())))
4169 } else if this
.look_ahead(1, |t
| t
.is_mutability()) &&
4170 this
.look_ahead(2, |t
| t
.is_keyword(keywords
::SelfValue
)) {
4172 let mutability
= try
!(this
.parse_mutability());
4173 Ok(SelfRegion(None
, mutability
, try
!(this
.expect_self_ident())))
4174 } else if this
.look_ahead(1, |t
| t
.is_lifetime()) &&
4175 this
.look_ahead(2, |t
| t
.is_keyword(keywords
::SelfValue
)) {
4177 let lifetime
= try
!(this
.parse_lifetime());
4178 Ok(SelfRegion(Some(lifetime
), MutImmutable
, try
!(this
.expect_self_ident())))
4179 } else if this
.look_ahead(1, |t
| t
.is_lifetime()) &&
4180 this
.look_ahead(2, |t
| t
.is_mutability()) &&
4181 this
.look_ahead(3, |t
| t
.is_keyword(keywords
::SelfValue
)) {
4183 let lifetime
= try
!(this
.parse_lifetime());
4184 let mutability
= try
!(this
.parse_mutability());
4185 Ok(SelfRegion(Some(lifetime
), mutability
, try
!(this
.expect_self_ident())))
4191 try
!(self.expect(&token
::OpenDelim(token
::Paren
)));
4193 // A bit of complexity and lookahead is needed here in order to be
4194 // backwards compatible.
4195 let lo
= self.span
.lo
;
4196 let mut self_ident_lo
= self.span
.lo
;
4197 let mut self_ident_hi
= self.span
.hi
;
4199 let mut mutbl_self
= MutImmutable
;
4200 let explicit_self
= match self.token
{
4201 token
::BinOp(token
::And
) => {
4202 let eself
= try
!(maybe_parse_borrowed_explicit_self(self));
4203 self_ident_lo
= self.last_span
.lo
;
4204 self_ident_hi
= self.last_span
.hi
;
4207 token
::BinOp(token
::Star
) => {
4208 // Possibly "*self" or "*mut self" -- not supported. Try to avoid
4209 // emitting cryptic "unexpected token" errors.
4211 let _mutability
= if self.token
.is_mutability() {
4212 try
!(self.parse_mutability())
4216 if self.is_self_ident() {
4217 let span
= self.span
;
4218 self.span_err(span
, "cannot pass self by raw pointer");
4221 // error case, making bogus self ident:
4222 SelfValue(special_idents
::self_
)
4224 token
::Ident(..) => {
4225 if self.is_self_ident() {
4226 let self_ident
= try
!(self.expect_self_ident());
4228 // Determine whether this is the fully explicit form, `self:
4230 if try
!(self.eat(&token
::Colon
) ){
4231 SelfExplicit(try
!(self.parse_ty_sum()), self_ident
)
4233 SelfValue(self_ident
)
4235 } else if self.token
.is_mutability() &&
4236 self.look_ahead(1, |t
| t
.is_keyword(keywords
::SelfValue
)) {
4237 mutbl_self
= try
!(self.parse_mutability());
4238 let self_ident
= try
!(self.expect_self_ident());
4240 // Determine whether this is the fully explicit form,
4242 if try
!(self.eat(&token
::Colon
) ){
4243 SelfExplicit(try
!(self.parse_ty_sum()), self_ident
)
4245 SelfValue(self_ident
)
4254 let explicit_self_sp
= mk_sp(self_ident_lo
, self_ident_hi
);
4256 // shared fall-through for the three cases below. borrowing prevents simply
4257 // writing this as a closure
4258 macro_rules
! parse_remaining_arguments
{
4261 // If we parsed a self type, expect a comma before the argument list.
4265 let sep
= seq_sep_trailing_allowed(token
::Comma
);
4266 let mut fn_inputs
= try
!(self.parse_seq_to_before_end(
4267 &token
::CloseDelim(token
::Paren
),
4271 fn_inputs
.insert(0, Arg
::new_self(explicit_self_sp
, mutbl_self
, $self_id
));
4274 token
::CloseDelim(token
::Paren
) => {
4275 vec
!(Arg
::new_self(explicit_self_sp
, mutbl_self
, $self_id
))
4278 let token_str
= self.this_token_to_string();
4279 return Err(self.fatal(&format
!("expected `,` or `)`, found `{}`",
4286 let fn_inputs
= match explicit_self
{
4288 let sep
= seq_sep_trailing_allowed(token
::Comma
);
4289 try
!(self.parse_seq_to_before_end(&token
::CloseDelim(token
::Paren
),
4292 SelfValue(id
) => parse_remaining_arguments
!(id
),
4293 SelfRegion(_
,_
,id
) => parse_remaining_arguments
!(id
),
4294 SelfExplicit(_
,id
) => parse_remaining_arguments
!(id
),
4298 try
!(self.expect(&token
::CloseDelim(token
::Paren
)));
4300 let hi
= self.span
.hi
;
4302 let ret_ty
= try
!(self.parse_ret_ty());
4304 let fn_decl
= P(FnDecl
{
4310 Ok((spanned(lo
, hi
, explicit_self
), fn_decl
))
4313 // parse the |arg, arg| header on a lambda
4314 fn parse_fn_block_decl(&mut self) -> PResult
<P
<FnDecl
>> {
4315 let inputs_captures
= {
4316 if try
!(self.eat(&token
::OrOr
) ){
4319 try
!(self.expect(&token
::BinOp(token
::Or
)));
4320 try
!(self.parse_obsolete_closure_kind());
4321 let args
= try
!(self.parse_seq_to_before_end(
4322 &token
::BinOp(token
::Or
),
4323 seq_sep_trailing_allowed(token
::Comma
),
4324 |p
| p
.parse_fn_block_arg()
4330 let output
= try
!(self.parse_ret_ty());
4333 inputs
: inputs_captures
,
4339 /// Parse the name and optional generic types of a function header.
4340 fn parse_fn_header(&mut self) -> PResult
<(Ident
, ast
::Generics
)> {
4341 let id
= try
!(self.parse_ident());
4342 let generics
= try
!(self.parse_generics());
4346 fn mk_item(&mut self, lo
: BytePos
, hi
: BytePos
, ident
: Ident
,
4347 node
: Item_
, vis
: Visibility
,
4348 attrs
: Vec
<Attribute
>) -> P
<Item
> {
4352 id
: ast
::DUMMY_NODE_ID
,
4359 /// Parse an item-position function declaration.
4360 fn parse_item_fn(&mut self,
4362 constness
: Constness
,
4364 -> PResult
<ItemInfo
> {
4365 let (ident
, mut generics
) = try
!(self.parse_fn_header());
4366 let decl
= try
!(self.parse_fn_decl(false));
4367 generics
.where_clause
= try
!(self.parse_where_clause());
4368 let (inner_attrs
, body
) = try
!(self.parse_inner_attrs_and_block());
4369 Ok((ident
, ItemFn(decl
, unsafety
, constness
, abi
, generics
, body
), Some(inner_attrs
)))
4372 /// true if we are looking at `const ID`, false for things like `const fn` etc
4373 pub fn is_const_item(&mut self) -> bool
{
4374 self.token
.is_keyword(keywords
::Const
) &&
4375 !self.look_ahead(1, |t
| t
.is_keyword(keywords
::Fn
))
4378 /// parses all the "front matter" for a `fn` declaration, up to
4379 /// and including the `fn` keyword:
4385 pub fn parse_fn_front_matter(&mut self) -> PResult
<(ast
::Constness
, ast
::Unsafety
, abi
::Abi
)> {
4386 let is_const_fn
= try
!(self.eat_keyword(keywords
::Const
));
4387 let (constness
, unsafety
, abi
) = if is_const_fn
{
4388 (Constness
::Const
, Unsafety
::Normal
, abi
::Rust
)
4390 let unsafety
= try
!(self.parse_unsafety());
4391 let abi
= if try
!(self.eat_keyword(keywords
::Extern
)) {
4392 try
!(self.parse_opt_abi()).unwrap_or(abi
::C
)
4396 (Constness
::NotConst
, unsafety
, abi
)
4398 try
!(self.expect_keyword(keywords
::Fn
));
4399 Ok((constness
, unsafety
, abi
))
4402 /// Parse an impl item.
4403 pub fn parse_impl_item(&mut self) -> PResult
<P
<ImplItem
>> {
4404 maybe_whole
!(no_clone
self, NtImplItem
);
4406 let mut attrs
= self.parse_outer_attributes();
4407 let lo
= self.span
.lo
;
4408 let vis
= try
!(self.parse_visibility());
4409 let (name
, node
) = if try
!(self.eat_keyword(keywords
::Type
)) {
4410 let name
= try
!(self.parse_ident());
4411 try
!(self.expect(&token
::Eq
));
4412 let typ
= try
!(self.parse_ty_sum());
4413 try
!(self.expect(&token
::Semi
));
4414 (name
, TypeImplItem(typ
))
4415 } else if self.is_const_item() {
4416 try
!(self.expect_keyword(keywords
::Const
));
4417 let name
= try
!(self.parse_ident());
4418 try
!(self.expect(&token
::Colon
));
4419 let typ
= try
!(self.parse_ty_sum());
4420 try
!(self.expect(&token
::Eq
));
4421 let expr
= try
!(self.parse_expr_nopanic());
4422 try
!(self.commit_expr_expecting(&expr
, token
::Semi
));
4423 (name
, ConstImplItem(typ
, expr
))
4425 let (name
, inner_attrs
, node
) = try
!(self.parse_impl_method(vis
));
4426 attrs
.extend(inner_attrs
);
4431 id
: ast
::DUMMY_NODE_ID
,
4432 span
: mk_sp(lo
, self.last_span
.hi
),
4440 fn complain_if_pub_macro(&mut self, visa
: Visibility
, span
: Span
) {
4443 self.span_err(span
, "can't qualify macro invocation with `pub`");
4444 self.fileline_help(span
, "try adjusting the macro to put `pub` inside \
4451 /// Parse a method or a macro invocation in a trait impl.
4452 fn parse_impl_method(&mut self, vis
: Visibility
)
4453 -> PResult
<(Ident
, Vec
<ast
::Attribute
>, ast
::ImplItem_
)> {
4454 // code copied from parse_macro_use_or_failure... abstraction!
4455 if !self.token
.is_any_keyword()
4456 && self.look_ahead(1, |t
| *t
== token
::Not
)
4457 && (self.look_ahead(2, |t
| *t
== token
::OpenDelim(token
::Paren
))
4458 || self.look_ahead(2, |t
| *t
== token
::OpenDelim(token
::Brace
))) {
4461 let last_span
= self.last_span
;
4462 self.complain_if_pub_macro(vis
, last_span
);
4464 let pth
= try
!(self.parse_path(NoTypesAllowed
));
4465 try
!(self.expect(&token
::Not
));
4467 // eat a matched-delimiter token tree:
4468 let delim
= try
!(self.expect_open_delim());
4469 let tts
= try
!(self.parse_seq_to_end(&token
::CloseDelim(delim
),
4471 |p
| p
.parse_token_tree()));
4472 let m_
= ast
::MacInvocTT(pth
, tts
, EMPTY_CTXT
);
4473 let m
: ast
::Mac
= codemap
::Spanned
{ node
: m_
,
4474 span
: mk_sp(self.span
.lo
,
4476 if delim
!= token
::Brace
{
4477 try
!(self.expect(&token
::Semi
))
4479 Ok((token
::special_idents
::invalid
, vec
![], ast
::MacImplItem(m
)))
4481 let (constness
, unsafety
, abi
) = try
!(self.parse_fn_front_matter());
4482 let ident
= try
!(self.parse_ident());
4483 let mut generics
= try
!(self.parse_generics());
4484 let (explicit_self
, decl
) = try
!(self.parse_fn_decl_with_self(|p
| {
4487 generics
.where_clause
= try
!(self.parse_where_clause());
4488 let (inner_attrs
, body
) = try
!(self.parse_inner_attrs_and_block());
4489 Ok((ident
, inner_attrs
, MethodImplItem(ast
::MethodSig
{
4492 explicit_self
: explicit_self
,
4494 constness
: constness
,
4500 /// Parse trait Foo { ... }
4501 fn parse_item_trait(&mut self, unsafety
: Unsafety
) -> PResult
<ItemInfo
> {
4503 let ident
= try
!(self.parse_ident());
4504 let mut tps
= try
!(self.parse_generics());
4506 // Parse supertrait bounds.
4507 let bounds
= try
!(self.parse_colon_then_ty_param_bounds(BoundParsingMode
::Bare
));
4509 tps
.where_clause
= try
!(self.parse_where_clause());
4511 let meths
= try
!(self.parse_trait_items());
4512 Ok((ident
, ItemTrait(unsafety
, tps
, bounds
, meths
), None
))
4515 /// Parses items implementations variants
4516 /// impl<T> Foo { ... }
4517 /// impl<T> ToString for &'static T { ... }
4518 /// impl Send for .. {}
4519 fn parse_item_impl(&mut self, unsafety
: ast
::Unsafety
) -> PResult
<ItemInfo
> {
4520 let impl_span
= self.span
;
4522 // First, parse type parameters if necessary.
4523 let mut generics
= try
!(self.parse_generics());
4525 // Special case: if the next identifier that follows is '(', don't
4526 // allow this to be parsed as a trait.
4527 let could_be_trait
= self.token
!= token
::OpenDelim(token
::Paren
);
4529 let neg_span
= self.span
;
4530 let polarity
= if try
!(self.eat(&token
::Not
) ){
4531 ast
::ImplPolarity
::Negative
4533 ast
::ImplPolarity
::Positive
4537 let mut ty
= try
!(self.parse_ty_sum());
4539 // Parse traits, if necessary.
4540 let opt_trait
= if could_be_trait
&& try
!(self.eat_keyword(keywords
::For
) ){
4541 // New-style trait. Reinterpret the type as a trait.
4543 TyPath(None
, ref path
) => {
4545 path
: (*path
).clone(),
4550 self.span_err(ty
.span
, "not a trait");
4556 ast
::ImplPolarity
::Negative
=> {
4557 // This is a negated type implementation
4558 // `impl !MyType {}`, which is not allowed.
4559 self.span_err(neg_span
, "inherent implementation can't be negated");
4566 if try
!(self.eat(&token
::DotDot
) ){
4567 if generics
.is_parameterized() {
4568 self.span_err(impl_span
, "default trait implementations are not \
4569 allowed to have generics");
4572 try
!(self.expect(&token
::OpenDelim(token
::Brace
)));
4573 try
!(self.expect(&token
::CloseDelim(token
::Brace
)));
4574 Ok((ast_util
::impl_pretty_name(&opt_trait
, None
),
4575 ItemDefaultImpl(unsafety
, opt_trait
.unwrap()), None
))
4577 if opt_trait
.is_some() {
4578 ty
= try
!(self.parse_ty_sum());
4580 generics
.where_clause
= try
!(self.parse_where_clause());
4582 try
!(self.expect(&token
::OpenDelim(token
::Brace
)));
4583 let attrs
= self.parse_inner_attributes();
4585 let mut impl_items
= vec
![];
4586 while !try
!(self.eat(&token
::CloseDelim(token
::Brace
))) {
4587 impl_items
.push(try
!(self.parse_impl_item()));
4590 Ok((ast_util
::impl_pretty_name(&opt_trait
, Some(&*ty
)),
4591 ItemImpl(unsafety
, polarity
, generics
, opt_trait
, ty
, impl_items
),
4596 /// Parse a::B<String,i32>
4597 fn parse_trait_ref(&mut self) -> PResult
<TraitRef
> {
4599 path
: try
!(self.parse_path(LifetimeAndTypesWithoutColons
)),
4600 ref_id
: ast
::DUMMY_NODE_ID
,
4604 fn parse_late_bound_lifetime_defs(&mut self) -> PResult
<Vec
<ast
::LifetimeDef
>> {
4605 if try
!(self.eat_keyword(keywords
::For
) ){
4606 try
!(self.expect(&token
::Lt
));
4607 let lifetime_defs
= try
!(self.parse_lifetime_defs());
4608 try
!(self.expect_gt());
4615 /// Parse for<'l> a::B<String,i32>
4616 fn parse_poly_trait_ref(&mut self) -> PResult
<PolyTraitRef
> {
4617 let lo
= self.span
.lo
;
4618 let lifetime_defs
= try
!(self.parse_late_bound_lifetime_defs());
4620 Ok(ast
::PolyTraitRef
{
4621 bound_lifetimes
: lifetime_defs
,
4622 trait_ref
: try
!(self.parse_trait_ref()),
4623 span
: mk_sp(lo
, self.last_span
.hi
),
4627 /// Parse struct Foo { ... }
4628 fn parse_item_struct(&mut self) -> PResult
<ItemInfo
> {
4629 let class_name
= try
!(self.parse_ident());
4630 let mut generics
= try
!(self.parse_generics());
4632 if try
!(self.eat(&token
::Colon
) ){
4633 let ty
= try
!(self.parse_ty_sum());
4634 self.span_err(ty
.span
, "`virtual` structs have been removed from the language");
4637 // There is a special case worth noting here, as reported in issue #17904.
4638 // If we are parsing a tuple struct it is the case that the where clause
4639 // should follow the field list. Like so:
4641 // struct Foo<T>(T) where T: Copy;
4643 // If we are parsing a normal record-style struct it is the case
4644 // that the where clause comes before the body, and after the generics.
4645 // So if we look ahead and see a brace or a where-clause we begin
4646 // parsing a record style struct.
4648 // Otherwise if we look ahead and see a paren we parse a tuple-style
4651 let (fields
, ctor_id
) = if self.token
.is_keyword(keywords
::Where
) {
4652 generics
.where_clause
= try
!(self.parse_where_clause());
4653 if try
!(self.eat(&token
::Semi
)) {
4654 // If we see a: `struct Foo<T> where T: Copy;` style decl.
4655 (Vec
::new(), Some(ast
::DUMMY_NODE_ID
))
4657 // If we see: `struct Foo<T> where T: Copy { ... }`
4658 (try
!(self.parse_record_struct_body(&class_name
)), None
)
4660 // No `where` so: `struct Foo<T>;`
4661 } else if try
!(self.eat(&token
::Semi
) ){
4662 (Vec
::new(), Some(ast
::DUMMY_NODE_ID
))
4663 // Record-style struct definition
4664 } else if self.token
== token
::OpenDelim(token
::Brace
) {
4665 let fields
= try
!(self.parse_record_struct_body(&class_name
));
4667 // Tuple-style struct definition with optional where-clause.
4669 let fields
= try
!(self.parse_tuple_struct_body(&class_name
, &mut generics
));
4670 (fields
, Some(ast
::DUMMY_NODE_ID
))
4674 ItemStruct(P(ast
::StructDef
{
4681 pub fn parse_record_struct_body(&mut self,
4682 class_name
: &ast
::Ident
) -> PResult
<Vec
<StructField
>> {
4683 let mut fields
= Vec
::new();
4684 if try
!(self.eat(&token
::OpenDelim(token
::Brace
)) ){
4685 while self.token
!= token
::CloseDelim(token
::Brace
) {
4686 fields
.push(try
!(self.parse_struct_decl_field(true)));
4689 if fields
.is_empty() {
4690 return Err(self.fatal(&format
!("unit-like struct definition should be \
4691 written as `struct {};`",
4692 token
::get_ident(class_name
.clone()))));
4697 let token_str
= self.this_token_to_string();
4698 return Err(self.fatal(&format
!("expected `where`, or `{}` after struct \
4699 name, found `{}`", "{",
4706 pub fn parse_tuple_struct_body(&mut self,
4707 class_name
: &ast
::Ident
,
4708 generics
: &mut ast
::Generics
)
4709 -> PResult
<Vec
<StructField
>> {
4710 // This is the case where we find `struct Foo<T>(T) where T: Copy;`
4711 if self.check(&token
::OpenDelim(token
::Paren
)) {
4712 let fields
= try
!(self.parse_unspanned_seq(
4713 &token
::OpenDelim(token
::Paren
),
4714 &token
::CloseDelim(token
::Paren
),
4715 seq_sep_trailing_allowed(token
::Comma
),
4717 let attrs
= p
.parse_outer_attributes();
4719 let struct_field_
= ast
::StructField_
{
4720 kind
: UnnamedField(try
!(p
.parse_visibility())),
4721 id
: ast
::DUMMY_NODE_ID
,
4722 ty
: try
!(p
.parse_ty_sum()),
4725 Ok(spanned(lo
, p
.span
.hi
, struct_field_
))
4728 if fields
.is_empty() {
4729 return Err(self.fatal(&format
!("unit-like struct definition should be \
4730 written as `struct {};`",
4731 token
::get_ident(class_name
.clone()))));
4734 generics
.where_clause
= try
!(self.parse_where_clause());
4735 try
!(self.expect(&token
::Semi
));
4737 // This is the case where we just see struct Foo<T> where T: Copy;
4738 } else if self.token
.is_keyword(keywords
::Where
) {
4739 generics
.where_clause
= try
!(self.parse_where_clause());
4740 try
!(self.expect(&token
::Semi
));
4742 // This case is where we see: `struct Foo<T>;`
4744 let token_str
= self.this_token_to_string();
4745 Err(self.fatal(&format
!("expected `where`, `{}`, `(`, or `;` after struct \
4746 name, found `{}`", "{", token_str
)))
4750 /// Parse a structure field declaration
4751 pub fn parse_single_struct_field(&mut self,
4753 attrs
: Vec
<Attribute
> )
4754 -> PResult
<StructField
> {
4755 let a_var
= try
!(self.parse_name_and_ty(vis
, attrs
));
4760 token
::CloseDelim(token
::Brace
) => {}
4762 let span
= self.span
;
4763 let token_str
= self.this_token_to_string();
4764 return Err(self.span_fatal_help(span
,
4765 &format
!("expected `,`, or `}}`, found `{}`",
4767 "struct fields should be separated by commas"))
4773 /// Parse an element of a struct definition
4774 fn parse_struct_decl_field(&mut self, allow_pub
: bool
) -> PResult
<StructField
> {
4776 let attrs
= self.parse_outer_attributes();
4778 if try
!(self.eat_keyword(keywords
::Pub
) ){
4780 let span
= self.last_span
;
4781 self.span_err(span
, "`pub` is not allowed here");
4783 return self.parse_single_struct_field(Public
, attrs
);
4786 return self.parse_single_struct_field(Inherited
, attrs
);
4789 /// Parse visibility: PUB or nothing
4790 fn parse_visibility(&mut self) -> PResult
<Visibility
> {
4791 if try
!(self.eat_keyword(keywords
::Pub
)) { Ok(Public) }
4792 else { Ok(Inherited) }
4795 /// Given a termination token, parse all of the items in a module
4796 fn parse_mod_items(&mut self, term
: &token
::Token
, inner_lo
: BytePos
) -> PResult
<Mod
> {
4797 let mut items
= vec
![];
4798 while let Some(item
) = try
!(self.parse_item_nopanic()) {
4802 if !try
!(self.eat(term
)) {
4803 let token_str
= self.this_token_to_string();
4804 return Err(self.fatal(&format
!("expected item, found `{}`", token_str
)));
4808 inner
: mk_sp(inner_lo
, self.span
.lo
),
4813 fn parse_item_const(&mut self, m
: Option
<Mutability
>) -> PResult
<ItemInfo
> {
4814 let id
= try
!(self.parse_ident());
4815 try
!(self.expect(&token
::Colon
));
4816 let ty
= try
!(self.parse_ty_sum());
4817 try
!(self.expect(&token
::Eq
));
4818 let e
= try
!(self.parse_expr_nopanic());
4819 try
!(self.commit_expr_expecting(&*e
, token
::Semi
));
4820 let item
= match m
{
4821 Some(m
) => ItemStatic(ty
, m
, e
),
4822 None
=> ItemConst(ty
, e
),
4824 Ok((id
, item
, None
))
4827 /// Parse a `mod <foo> { ... }` or `mod <foo>;` item
4828 fn parse_item_mod(&mut self, outer_attrs
: &[Attribute
]) -> PResult
<ItemInfo
> {
4829 let id_span
= self.span
;
4830 let id
= try
!(self.parse_ident());
4831 if self.check(&token
::Semi
) {
4833 // This mod is in an external file. Let's go get it!
4834 let (m
, attrs
) = try
!(self.eval_src_mod(id
, outer_attrs
, id_span
));
4835 Ok((id
, m
, Some(attrs
)))
4837 self.push_mod_path(id
, outer_attrs
);
4838 try
!(self.expect(&token
::OpenDelim(token
::Brace
)));
4839 let mod_inner_lo
= self.span
.lo
;
4840 let old_owns_directory
= self.owns_directory
;
4841 self.owns_directory
= true;
4842 let attrs
= self.parse_inner_attributes();
4843 let m
= try
!(self.parse_mod_items(&token
::CloseDelim(token
::Brace
), mod_inner_lo
));
4844 self.owns_directory
= old_owns_directory
;
4845 self.pop_mod_path();
4846 Ok((id
, ItemMod(m
), Some(attrs
)))
4850 fn push_mod_path(&mut self, id
: Ident
, attrs
: &[Attribute
]) {
4851 let default_path
= self.id_to_interned_str(id
);
4852 let file_path
= match ::attr
::first_attr_value_str_by_name(attrs
,
4855 None
=> default_path
,
4857 self.mod_path_stack
.push(file_path
)
4860 fn pop_mod_path(&mut self) {
4861 self.mod_path_stack
.pop().unwrap();
4864 /// Read a module from a source file.
4865 fn eval_src_mod(&mut self,
4867 outer_attrs
: &[ast
::Attribute
],
4869 -> PResult
<(ast
::Item_
, Vec
<ast
::Attribute
> )> {
4870 let mut prefix
= PathBuf
::from(&self.sess
.codemap().span_to_filename(self.span
));
4872 let mut dir_path
= prefix
;
4873 for part
in &self.mod_path_stack
{
4874 dir_path
.push(&**part
);
4876 let mod_string
= token
::get_ident(id
);
4877 let (file_path
, owns_directory
) = match ::attr
::first_attr_value_str_by_name(
4878 outer_attrs
, "path") {
4879 Some(d
) => (dir_path
.join(&*d
), true),
4881 let mod_name
= mod_string
.to_string();
4882 let default_path_str
= format
!("{}.rs", mod_name
);
4883 let secondary_path_str
= format
!("{}/mod.rs", mod_name
);
4884 let default_path
= dir_path
.join(&default_path_str
[..]);
4885 let secondary_path
= dir_path
.join(&secondary_path_str
[..]);
4886 let default_exists
= self.sess
.codemap().file_exists(&default_path
);
4887 let secondary_exists
= self.sess
.codemap().file_exists(&secondary_path
);
4889 if !self.owns_directory
{
4890 self.span_err(id_sp
,
4891 "cannot declare a new module at this location");
4892 let this_module
= match self.mod_path_stack
.last() {
4893 Some(name
) => name
.to_string(),
4894 None
=> self.root_module_name
.as_ref().unwrap().clone(),
4896 self.span_note(id_sp
,
4897 &format
!("maybe move this module `{0}` \
4898 to its own directory via \
4901 if default_exists
|| secondary_exists
{
4902 self.span_note(id_sp
,
4903 &format
!("... or maybe `use` the module \
4904 `{}` instead of possibly \
4908 self.abort_if_errors();
4911 match (default_exists
, secondary_exists
) {
4912 (true, false) => (default_path
, false),
4913 (false, true) => (secondary_path
, true),
4915 return Err(self.span_fatal_help(id_sp
,
4916 &format
!("file not found for module `{}`",
4918 &format
!("name the file either {} or {} inside \
4919 the directory {:?}",
4922 dir_path
.display())));
4925 return Err(self.span_fatal_help(
4927 &format
!("file for module `{}` found at both {} \
4931 secondary_path_str
),
4932 "delete or rename one of them to remove the ambiguity"));
4938 self.eval_src_mod_from_path(file_path
, owns_directory
,
4939 mod_string
.to_string(), id_sp
)
4942 fn eval_src_mod_from_path(&mut self,
4944 owns_directory
: bool
,
4946 id_sp
: Span
) -> PResult
<(ast
::Item_
, Vec
<ast
::Attribute
> )> {
4947 let mut included_mod_stack
= self.sess
.included_mod_stack
.borrow_mut();
4948 match included_mod_stack
.iter().position(|p
| *p
== path
) {
4950 let mut err
= String
::from("circular modules: ");
4951 let len
= included_mod_stack
.len();
4952 for p
in &included_mod_stack
[i
.. len
] {
4953 err
.push_str(&p
.to_string_lossy());
4954 err
.push_str(" -> ");
4956 err
.push_str(&path
.to_string_lossy());
4957 return Err(self.span_fatal(id_sp
, &err
[..]));
4961 included_mod_stack
.push(path
.clone());
4962 drop(included_mod_stack
);
4965 new_sub_parser_from_file(self.sess
,
4971 let mod_inner_lo
= p0
.span
.lo
;
4972 let mod_attrs
= p0
.parse_inner_attributes();
4973 let m0
= try
!(p0
.parse_mod_items(&token
::Eof
, mod_inner_lo
));
4974 self.sess
.included_mod_stack
.borrow_mut().pop();
4975 Ok((ast
::ItemMod(m0
), mod_attrs
))
4978 /// Parse a function declaration from a foreign module
4979 fn parse_item_foreign_fn(&mut self, vis
: ast
::Visibility
,
4980 attrs
: Vec
<Attribute
>) -> PResult
<P
<ForeignItem
>> {
4981 let lo
= self.span
.lo
;
4982 try
!(self.expect_keyword(keywords
::Fn
));
4984 let (ident
, mut generics
) = try
!(self.parse_fn_header());
4985 let decl
= try
!(self.parse_fn_decl(true));
4986 generics
.where_clause
= try
!(self.parse_where_clause());
4987 let hi
= self.span
.hi
;
4988 try
!(self.expect(&token
::Semi
));
4989 Ok(P(ast
::ForeignItem
{
4992 node
: ForeignItemFn(decl
, generics
),
4993 id
: ast
::DUMMY_NODE_ID
,
4994 span
: mk_sp(lo
, hi
),
4999 /// Parse a static item from a foreign module
5000 fn parse_item_foreign_static(&mut self, vis
: ast
::Visibility
,
5001 attrs
: Vec
<Attribute
>) -> PResult
<P
<ForeignItem
>> {
5002 let lo
= self.span
.lo
;
5004 try
!(self.expect_keyword(keywords
::Static
));
5005 let mutbl
= try
!(self.eat_keyword(keywords
::Mut
));
5007 let ident
= try
!(self.parse_ident());
5008 try
!(self.expect(&token
::Colon
));
5009 let ty
= try
!(self.parse_ty_sum());
5010 let hi
= self.span
.hi
;
5011 try
!(self.expect(&token
::Semi
));
5015 node
: ForeignItemStatic(ty
, mutbl
),
5016 id
: ast
::DUMMY_NODE_ID
,
5017 span
: mk_sp(lo
, hi
),
5022 /// Parse extern crate links
5026 /// extern crate foo;
5027 /// extern crate bar as foo;
5028 fn parse_item_extern_crate(&mut self,
5030 visibility
: Visibility
,
5031 attrs
: Vec
<Attribute
>)
5032 -> PResult
<P
<Item
>> {
5034 let crate_name
= try
!(self.parse_ident());
5035 let (maybe_path
, ident
) = if try
!(self.eat_keyword(keywords
::As
)) {
5036 (Some(crate_name
.name
), try
!(self.parse_ident()))
5040 try
!(self.expect(&token
::Semi
));
5042 let last_span
= self.last_span
;
5046 ItemExternCrate(maybe_path
),
5051 /// Parse `extern` for foreign ABIs
5054 /// `extern` is expected to have been
5055 /// consumed before calling this method
5061 fn parse_item_foreign_mod(&mut self,
5063 opt_abi
: Option
<abi
::Abi
>,
5064 visibility
: Visibility
,
5065 mut attrs
: Vec
<Attribute
>)
5066 -> PResult
<P
<Item
>> {
5067 try
!(self.expect(&token
::OpenDelim(token
::Brace
)));
5069 let abi
= opt_abi
.unwrap_or(abi
::C
);
5071 attrs
.extend(self.parse_inner_attributes());
5073 let mut foreign_items
= vec
![];
5074 while let Some(item
) = try
!(self.parse_foreign_item()) {
5075 foreign_items
.push(item
);
5077 try
!(self.expect(&token
::CloseDelim(token
::Brace
)));
5079 let last_span
= self.last_span
;
5080 let m
= ast
::ForeignMod
{
5082 items
: foreign_items
5086 special_idents
::invalid
,
5092 /// Parse type Foo = Bar;
5093 fn parse_item_type(&mut self) -> PResult
<ItemInfo
> {
5094 let ident
= try
!(self.parse_ident());
5095 let mut tps
= try
!(self.parse_generics());
5096 tps
.where_clause
= try
!(self.parse_where_clause());
5097 try
!(self.expect(&token
::Eq
));
5098 let ty
= try
!(self.parse_ty_sum());
5099 try
!(self.expect(&token
::Semi
));
5100 Ok((ident
, ItemTy(ty
, tps
), None
))
5103 /// Parse a structure-like enum variant definition
5104 /// this should probably be renamed or refactored...
5105 fn parse_struct_def(&mut self) -> PResult
<P
<StructDef
>> {
5106 let mut fields
: Vec
<StructField
> = Vec
::new();
5107 while self.token
!= token
::CloseDelim(token
::Brace
) {
5108 fields
.push(try
!(self.parse_struct_decl_field(false)));
5118 /// Parse the part of an "enum" decl following the '{'
5119 fn parse_enum_def(&mut self, _generics
: &ast
::Generics
) -> PResult
<EnumDef
> {
5120 let mut variants
= Vec
::new();
5121 let mut all_nullary
= true;
5122 let mut any_disr
= None
;
5123 while self.token
!= token
::CloseDelim(token
::Brace
) {
5124 let variant_attrs
= self.parse_outer_attributes();
5125 let vlo
= self.span
.lo
;
5127 let vis
= try
!(self.parse_visibility());
5131 let mut args
= Vec
::new();
5132 let mut disr_expr
= None
;
5133 ident
= try
!(self.parse_ident());
5134 if try
!(self.eat(&token
::OpenDelim(token
::Brace
)) ){
5135 // Parse a struct variant.
5136 all_nullary
= false;
5137 let start_span
= self.span
;
5138 let struct_def
= try
!(self.parse_struct_def());
5139 if struct_def
.fields
.is_empty() {
5140 self.span_err(start_span
,
5141 &format
!("unit-like struct variant should be written \
5142 without braces, as `{},`",
5143 token
::get_ident(ident
)));
5145 kind
= StructVariantKind(struct_def
);
5146 } else if self.check(&token
::OpenDelim(token
::Paren
)) {
5147 all_nullary
= false;
5148 let arg_tys
= try
!(self.parse_enum_variant_seq(
5149 &token
::OpenDelim(token
::Paren
),
5150 &token
::CloseDelim(token
::Paren
),
5151 seq_sep_trailing_allowed(token
::Comma
),
5152 |p
| p
.parse_ty_sum()
5155 args
.push(ast
::VariantArg
{
5157 id
: ast
::DUMMY_NODE_ID
,
5160 kind
= TupleVariantKind(args
);
5161 } else if try
!(self.eat(&token
::Eq
) ){
5162 disr_expr
= Some(try
!(self.parse_expr_nopanic()));
5163 any_disr
= disr_expr
.as_ref().map(|expr
| expr
.span
);
5164 kind
= TupleVariantKind(args
);
5166 kind
= TupleVariantKind(Vec
::new());
5169 let vr
= ast
::Variant_
{
5171 attrs
: variant_attrs
,
5173 id
: ast
::DUMMY_NODE_ID
,
5174 disr_expr
: disr_expr
,
5177 variants
.push(P(spanned(vlo
, self.last_span
.hi
, vr
)));
5179 if !try
!(self.eat(&token
::Comma
)) { break; }
5181 try
!(self.expect(&token
::CloseDelim(token
::Brace
)));
5183 Some(disr_span
) if !all_nullary
=>
5184 self.span_err(disr_span
,
5185 "discriminator values can only be used with a c-like enum"),
5189 Ok(ast
::EnumDef { variants: variants }
)
5192 /// Parse an "enum" declaration
5193 fn parse_item_enum(&mut self) -> PResult
<ItemInfo
> {
5194 let id
= try
!(self.parse_ident());
5195 let mut generics
= try
!(self.parse_generics());
5196 generics
.where_clause
= try
!(self.parse_where_clause());
5197 try
!(self.expect(&token
::OpenDelim(token
::Brace
)));
5199 let enum_definition
= try
!(self.parse_enum_def(&generics
));
5200 Ok((id
, ItemEnum(enum_definition
, generics
), None
))
5203 /// Parses a string as an ABI spec on an extern type or module. Consumes
5204 /// the `extern` keyword, if one is found.
5205 fn parse_opt_abi(&mut self) -> PResult
<Option
<abi
::Abi
>> {
5207 token
::Literal(token
::Str_(s
), suf
) | token
::Literal(token
::StrRaw(s
, _
), suf
) => {
5209 self.expect_no_suffix(sp
, "ABI spec", suf
);
5211 let the_string
= s
.as_str();
5212 match abi
::lookup(the_string
) {
5213 Some(abi
) => Ok(Some(abi
)),
5215 let last_span
= self.last_span
;
5218 &format
!("illegal ABI: expected one of [{}], \
5220 abi
::all_names().connect(", "),
5231 /// Parse one of the items allowed by the flags.
5232 /// NB: this function no longer parses the items inside an
5234 fn parse_item_(&mut self, attrs
: Vec
<Attribute
>,
5235 macros_allowed
: bool
) -> PResult
<Option
<P
<Item
>>> {
5236 let nt_item
= match self.token
{
5237 token
::Interpolated(token
::NtItem(ref item
)) => {
5238 Some((**item
).clone())
5245 let mut attrs
= attrs
;
5246 mem
::swap(&mut item
.attrs
, &mut attrs
);
5247 item
.attrs
.extend(attrs
);
5248 return Ok(Some(P(item
)));
5253 let lo
= self.span
.lo
;
5255 let visibility
= try
!(self.parse_visibility());
5257 if try
!(self.eat_keyword(keywords
::Use
) ){
5259 let item_
= ItemUse(try
!(self.parse_view_path()));
5260 try
!(self.expect(&token
::Semi
));
5262 let last_span
= self.last_span
;
5263 let item
= self.mk_item(lo
,
5265 token
::special_idents
::invalid
,
5269 return Ok(Some(item
));
5272 if try
!(self.eat_keyword(keywords
::Extern
)) {
5273 if try
!(self.eat_keyword(keywords
::Crate
)) {
5274 return Ok(Some(try
!(self.parse_item_extern_crate(lo
, visibility
, attrs
))));
5277 let opt_abi
= try
!(self.parse_opt_abi());
5279 if try
!(self.eat_keyword(keywords
::Fn
) ){
5280 // EXTERN FUNCTION ITEM
5281 let abi
= opt_abi
.unwrap_or(abi
::C
);
5282 let (ident
, item_
, extra_attrs
) =
5283 try
!(self.parse_item_fn(Unsafety
::Normal
, Constness
::NotConst
, abi
));
5284 let last_span
= self.last_span
;
5285 let item
= self.mk_item(lo
,
5290 maybe_append(attrs
, extra_attrs
));
5291 return Ok(Some(item
));
5292 } else if self.check(&token
::OpenDelim(token
::Brace
)) {
5293 return Ok(Some(try
!(self.parse_item_foreign_mod(lo
, opt_abi
, visibility
, attrs
))));
5296 try
!(self.expect_one_of(&[], &[]));
5299 if try
!(self.eat_keyword_noexpect(keywords
::Virtual
) ){
5300 let span
= self.span
;
5301 self.span_err(span
, "`virtual` structs have been removed from the language");
5304 if try
!(self.eat_keyword(keywords
::Static
) ){
5306 let m
= if try
!(self.eat_keyword(keywords
::Mut
)) {MutMutable}
else {MutImmutable}
;
5307 let (ident
, item_
, extra_attrs
) = try
!(self.parse_item_const(Some(m
)));
5308 let last_span
= self.last_span
;
5309 let item
= self.mk_item(lo
,
5314 maybe_append(attrs
, extra_attrs
));
5315 return Ok(Some(item
));
5317 if try
!(self.eat_keyword(keywords
::Const
) ){
5318 if self.check_keyword(keywords
::Fn
) {
5319 // CONST FUNCTION ITEM
5321 let (ident
, item_
, extra_attrs
) =
5322 try
!(self.parse_item_fn(Unsafety
::Normal
, Constness
::Const
, abi
::Rust
));
5323 let last_span
= self.last_span
;
5324 let item
= self.mk_item(lo
,
5329 maybe_append(attrs
, extra_attrs
));
5330 return Ok(Some(item
));
5334 if try
!(self.eat_keyword(keywords
::Mut
) ){
5335 let last_span
= self.last_span
;
5336 self.span_err(last_span
, "const globals cannot be mutable");
5337 self.fileline_help(last_span
, "did you mean to declare a static?");
5339 let (ident
, item_
, extra_attrs
) = try
!(self.parse_item_const(None
));
5340 let last_span
= self.last_span
;
5341 let item
= self.mk_item(lo
,
5346 maybe_append(attrs
, extra_attrs
));
5347 return Ok(Some(item
));
5349 if self.check_keyword(keywords
::Unsafe
) &&
5350 self.look_ahead(1, |t
| t
.is_keyword(keywords
::Trait
))
5352 // UNSAFE TRAIT ITEM
5353 try
!(self.expect_keyword(keywords
::Unsafe
));
5354 try
!(self.expect_keyword(keywords
::Trait
));
5355 let (ident
, item_
, extra_attrs
) =
5356 try
!(self.parse_item_trait(ast
::Unsafety
::Unsafe
));
5357 let last_span
= self.last_span
;
5358 let item
= self.mk_item(lo
,
5363 maybe_append(attrs
, extra_attrs
));
5364 return Ok(Some(item
));
5366 if self.check_keyword(keywords
::Unsafe
) &&
5367 self.look_ahead(1, |t
| t
.is_keyword(keywords
::Impl
))
5370 try
!(self.expect_keyword(keywords
::Unsafe
));
5371 try
!(self.expect_keyword(keywords
::Impl
));
5372 let (ident
, item_
, extra_attrs
) = try
!(self.parse_item_impl(ast
::Unsafety
::Unsafe
));
5373 let last_span
= self.last_span
;
5374 let item
= self.mk_item(lo
,
5379 maybe_append(attrs
, extra_attrs
));
5380 return Ok(Some(item
));
5382 if self.check_keyword(keywords
::Fn
) {
5385 let (ident
, item_
, extra_attrs
) =
5386 try
!(self.parse_item_fn(Unsafety
::Normal
, Constness
::NotConst
, abi
::Rust
));
5387 let last_span
= self.last_span
;
5388 let item
= self.mk_item(lo
,
5393 maybe_append(attrs
, extra_attrs
));
5394 return Ok(Some(item
));
5396 if self.check_keyword(keywords
::Unsafe
)
5397 && self.look_ahead(1, |t
| *t
!= token
::OpenDelim(token
::Brace
)) {
5398 // UNSAFE FUNCTION ITEM
5400 let abi
= if try
!(self.eat_keyword(keywords
::Extern
) ){
5401 try
!(self.parse_opt_abi()).unwrap_or(abi
::C
)
5405 try
!(self.expect_keyword(keywords
::Fn
));
5406 let (ident
, item_
, extra_attrs
) =
5407 try
!(self.parse_item_fn(Unsafety
::Unsafe
, Constness
::NotConst
, abi
));
5408 let last_span
= self.last_span
;
5409 let item
= self.mk_item(lo
,
5414 maybe_append(attrs
, extra_attrs
));
5415 return Ok(Some(item
));
5417 if try
!(self.eat_keyword(keywords
::Mod
) ){
5419 let (ident
, item_
, extra_attrs
) =
5420 try
!(self.parse_item_mod(&attrs
[..]));
5421 let last_span
= self.last_span
;
5422 let item
= self.mk_item(lo
,
5427 maybe_append(attrs
, extra_attrs
));
5428 return Ok(Some(item
));
5430 if try
!(self.eat_keyword(keywords
::Type
) ){
5432 let (ident
, item_
, extra_attrs
) = try
!(self.parse_item_type());
5433 let last_span
= self.last_span
;
5434 let item
= self.mk_item(lo
,
5439 maybe_append(attrs
, extra_attrs
));
5440 return Ok(Some(item
));
5442 if try
!(self.eat_keyword(keywords
::Enum
) ){
5444 let (ident
, item_
, extra_attrs
) = try
!(self.parse_item_enum());
5445 let last_span
= self.last_span
;
5446 let item
= self.mk_item(lo
,
5451 maybe_append(attrs
, extra_attrs
));
5452 return Ok(Some(item
));
5454 if try
!(self.eat_keyword(keywords
::Trait
) ){
5456 let (ident
, item_
, extra_attrs
) =
5457 try
!(self.parse_item_trait(ast
::Unsafety
::Normal
));
5458 let last_span
= self.last_span
;
5459 let item
= self.mk_item(lo
,
5464 maybe_append(attrs
, extra_attrs
));
5465 return Ok(Some(item
));
5467 if try
!(self.eat_keyword(keywords
::Impl
) ){
5469 let (ident
, item_
, extra_attrs
) = try
!(self.parse_item_impl(ast
::Unsafety
::Normal
));
5470 let last_span
= self.last_span
;
5471 let item
= self.mk_item(lo
,
5476 maybe_append(attrs
, extra_attrs
));
5477 return Ok(Some(item
));
5479 if try
!(self.eat_keyword(keywords
::Struct
) ){
5481 let (ident
, item_
, extra_attrs
) = try
!(self.parse_item_struct());
5482 let last_span
= self.last_span
;
5483 let item
= self.mk_item(lo
,
5488 maybe_append(attrs
, extra_attrs
));
5489 return Ok(Some(item
));
5491 self.parse_macro_use_or_failure(attrs
,macros_allowed
,lo
,visibility
)
5494 /// Parse a foreign item.
5495 fn parse_foreign_item(&mut self) -> PResult
<Option
<P
<ForeignItem
>>> {
5496 let attrs
= self.parse_outer_attributes();
5497 let lo
= self.span
.lo
;
5498 let visibility
= try
!(self.parse_visibility());
5500 if self.check_keyword(keywords
::Static
) {
5501 // FOREIGN STATIC ITEM
5502 return Ok(Some(try
!(self.parse_item_foreign_static(visibility
, attrs
))));
5504 if self.check_keyword(keywords
::Fn
) || self.check_keyword(keywords
::Unsafe
) {
5505 // FOREIGN FUNCTION ITEM
5506 return Ok(Some(try
!(self.parse_item_foreign_fn(visibility
, attrs
))));
5509 // FIXME #5668: this will occur for a macro invocation:
5510 match try
!(self.parse_macro_use_or_failure(attrs
, true, lo
, visibility
)) {
5512 return Err(self.span_fatal(item
.span
, "macros cannot expand to foreign items"));
5518 /// This is the fall-through for parsing items.
5519 fn parse_macro_use_or_failure(
5521 attrs
: Vec
<Attribute
> ,
5522 macros_allowed
: bool
,
5524 visibility
: Visibility
5525 ) -> PResult
<Option
<P
<Item
>>> {
5526 if macros_allowed
&& !self.token
.is_any_keyword()
5527 && self.look_ahead(1, |t
| *t
== token
::Not
)
5528 && (self.look_ahead(2, |t
| t
.is_plain_ident())
5529 || self.look_ahead(2, |t
| *t
== token
::OpenDelim(token
::Paren
))
5530 || self.look_ahead(2, |t
| *t
== token
::OpenDelim(token
::Brace
))) {
5531 // MACRO INVOCATION ITEM
5533 let last_span
= self.last_span
;
5534 self.complain_if_pub_macro(visibility
, last_span
);
5537 let pth
= try
!(self.parse_path(NoTypesAllowed
));
5538 try
!(self.expect(&token
::Not
));
5540 // a 'special' identifier (like what `macro_rules!` uses)
5541 // is optional. We should eventually unify invoc syntax
5543 let id
= if self.token
.is_plain_ident() {
5544 try
!(self.parse_ident())
5546 token
::special_idents
::invalid
// no special identifier
5548 // eat a matched-delimiter token tree:
5549 let delim
= try
!(self.expect_open_delim());
5550 let tts
= try
!(self.parse_seq_to_end(&token
::CloseDelim(delim
),
5552 |p
| p
.parse_token_tree()));
5553 // single-variant-enum... :
5554 let m
= ast
::MacInvocTT(pth
, tts
, EMPTY_CTXT
);
5555 let m
: ast
::Mac
= codemap
::Spanned
{ node
: m
,
5556 span
: mk_sp(self.span
.lo
,
5559 if delim
!= token
::Brace
{
5560 if !try
!(self.eat(&token
::Semi
) ){
5561 let last_span
= self.last_span
;
5562 self.span_err(last_span
,
5563 "macros that expand to items must either \
5564 be surrounded with braces or followed by \
5569 let item_
= ItemMac(m
);
5570 let last_span
= self.last_span
;
5571 let item
= self.mk_item(lo
,
5577 return Ok(Some(item
));
5580 // FAILURE TO PARSE ITEM
5584 let last_span
= self.last_span
;
5585 return Err(self.span_fatal(last_span
, "unmatched visibility `pub`"));
5589 if !attrs
.is_empty() {
5590 self.expected_item_err(&attrs
);
5595 pub fn parse_item_nopanic(&mut self) -> PResult
<Option
<P
<Item
>>> {
5596 let attrs
= self.parse_outer_attributes();
5597 self.parse_item_(attrs
, true)
5601 /// Matches view_path : MOD? non_global_path as IDENT
5602 /// | MOD? non_global_path MOD_SEP LBRACE RBRACE
5603 /// | MOD? non_global_path MOD_SEP LBRACE ident_seq RBRACE
5604 /// | MOD? non_global_path MOD_SEP STAR
5605 /// | MOD? non_global_path
5606 fn parse_view_path(&mut self) -> PResult
<P
<ViewPath
>> {
5607 let lo
= self.span
.lo
;
5609 // Allow a leading :: because the paths are absolute either way.
5610 // This occurs with "use $crate::..." in macros.
5611 try
!(self.eat(&token
::ModSep
));
5613 if self.check(&token
::OpenDelim(token
::Brace
)) {
5615 let idents
= try
!(self.parse_unspanned_seq(
5616 &token
::OpenDelim(token
::Brace
),
5617 &token
::CloseDelim(token
::Brace
),
5618 seq_sep_trailing_allowed(token
::Comma
),
5619 |p
| p
.parse_path_list_item()));
5620 let path
= ast
::Path
{
5621 span
: mk_sp(lo
, self.span
.hi
),
5623 segments
: Vec
::new()
5625 return Ok(P(spanned(lo
, self.span
.hi
, ViewPathList(path
, idents
))));
5628 let first_ident
= try
!(self.parse_ident());
5629 let mut path
= vec
!(first_ident
);
5630 if let token
::ModSep
= self.token
{
5631 // foo::bar or foo::{a,b,c} or foo::*
5632 while self.check(&token
::ModSep
) {
5636 token
::Ident(..) => {
5637 let ident
= try
!(self.parse_ident());
5641 // foo::bar::{a,b,c}
5642 token
::OpenDelim(token
::Brace
) => {
5643 let idents
= try
!(self.parse_unspanned_seq(
5644 &token
::OpenDelim(token
::Brace
),
5645 &token
::CloseDelim(token
::Brace
),
5646 seq_sep_trailing_allowed(token
::Comma
),
5647 |p
| p
.parse_path_list_item()
5649 let path
= ast
::Path
{
5650 span
: mk_sp(lo
, self.span
.hi
),
5652 segments
: path
.into_iter().map(|identifier
| {
5654 identifier
: identifier
,
5655 parameters
: ast
::PathParameters
::none(),
5659 return Ok(P(spanned(lo
, self.span
.hi
, ViewPathList(path
, idents
))));
5663 token
::BinOp(token
::Star
) => {
5665 let path
= ast
::Path
{
5666 span
: mk_sp(lo
, self.span
.hi
),
5668 segments
: path
.into_iter().map(|identifier
| {
5670 identifier
: identifier
,
5671 parameters
: ast
::PathParameters
::none(),
5675 return Ok(P(spanned(lo
, self.span
.hi
, ViewPathGlob(path
))));
5678 // fall-through for case foo::bar::;
5680 self.span_err(self.span
, "expected identifier or `{` or `*`, found `;`");
5687 let mut rename_to
= path
[path
.len() - 1];
5688 let path
= ast
::Path
{
5689 span
: mk_sp(lo
, self.last_span
.hi
),
5691 segments
: path
.into_iter().map(|identifier
| {
5693 identifier
: identifier
,
5694 parameters
: ast
::PathParameters
::none(),
5698 if try
!(self.eat_keyword(keywords
::As
)) {
5699 rename_to
= try
!(self.parse_ident())
5701 Ok(P(spanned(lo
, self.last_span
.hi
, ViewPathSimple(rename_to
, path
))))
5704 /// Parses a source module as a crate. This is the main
5705 /// entry point for the parser.
5706 pub fn parse_crate_mod(&mut self) -> PResult
<Crate
> {
5707 let lo
= self.span
.lo
;
5709 attrs
: self.parse_inner_attributes(),
5710 module
: try
!(self.parse_mod_items(&token
::Eof
, lo
)),
5711 config
: self.cfg
.clone(),
5712 span
: mk_sp(lo
, self.span
.lo
),
5713 exported_macros
: Vec
::new(),
5717 pub fn parse_optional_str(&mut self)
5718 -> PResult
<Option
<(InternedString
,
5720 Option
<ast
::Name
>)>> {
5721 let ret
= match self.token
{
5722 token
::Literal(token
::Str_(s
), suf
) => {
5723 (self.id_to_interned_str(s
.ident()), ast
::CookedStr
, suf
)
5725 token
::Literal(token
::StrRaw(s
, n
), suf
) => {
5726 (self.id_to_interned_str(s
.ident()), ast
::RawStr(n
), suf
)
5728 _
=> return Ok(None
)
5734 pub fn parse_str(&mut self) -> PResult
<(InternedString
, StrStyle
)> {
5735 match try
!(self.parse_optional_str()) {
5736 Some((s
, style
, suf
)) => {
5737 let sp
= self.last_span
;
5738 self.expect_no_suffix(sp
, "str literal", suf
);
5741 _
=> Err(self.fatal("expected string literal"))