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syntax: Parses && as & & whenever appropriate. #13576

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Merged
bors merged 1 commit into from
Apr 18, 2014
+95 −38
Merged

syntax: Parses && as & & whenever appropriate. #13576

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92 changes: 54 additions & 38 deletions src/libsyntax/parse/parser.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
Expand Down Expand Up @@ -542,6 +542,26 @@ impl<'a> Parser<'a> {
}
}

// Expect and consume an `&`. If `&&` is seen, replace it with a single
// `&` and continue. If an `&` is not seen, signal an error.
fn expect_and(&mut self) {
match self.token {
token::BINOP(token::AND) => self.bump(),
token::ANDAND => {
let lo = self.span.lo + BytePos(1);
self.replace_token(token::BINOP(token::AND), lo, self.span.hi)
}
_ => {
let token_str = self.this_token_to_str();
let found_token =
Parser::token_to_str(&token::BINOP(token::AND));
self.fatal(format!("expected `{}`, found `{}`",
found_token,
token_str))
}
}
}

// Expect and consume a `|`. If `||` is seen, replace it with a single
// `|` and continue. If a `|` is not seen, signal an error.
fn expect_or(&mut self) {
Expand Down Expand Up @@ -1218,9 +1238,10 @@ impl<'a> Parser<'a> {
};
self.expect(&token::RBRACKET);
t
} else if self.token == token::BINOP(token::AND) {
} else if self.token == token::BINOP(token::AND) ||
self.token == token::ANDAND {
// BORROWED POINTER
self.bump();
self.expect_and();
self.parse_borrowed_pointee()
} else if self.is_keyword(keywords::Extern) ||
self.token_is_bare_fn_keyword() {
Expand Down Expand Up @@ -2169,42 +2190,37 @@ impl<'a> Parser<'a> {
hi = e.span.hi;
ex = self.mk_unary(UnNot, e);
}
token::BINOP(b) => {
match b {
token::MINUS => {
self.bump();
let e = self.parse_prefix_expr();
hi = e.span.hi;
ex = self.mk_unary(UnNeg, e);
token::BINOP(token::MINUS) => {
self.bump();
let e = self.parse_prefix_expr();
hi = e.span.hi;
ex = self.mk_unary(UnNeg, e);
}
token::BINOP(token::STAR) => {
self.bump();
let e = self.parse_prefix_expr();
hi = e.span.hi;
ex = self.mk_unary(UnDeref, e);
}
token::BINOP(token::AND) | token::ANDAND => {
self.expect_and();
let _lt = self.parse_opt_lifetime();
let m = self.parse_mutability();
let e = self.parse_prefix_expr();
hi = e.span.hi;
// HACK: turn &[...] into a &-vec
ex = match e.node {
ExprVec(..) if m == MutImmutable => {
ExprVstore(e, ExprVstoreSlice)
}
token::STAR => {
self.bump();
let e = self.parse_prefix_expr();
hi = e.span.hi;
ex = self.mk_unary(UnDeref, e);
ExprLit(lit) if lit_is_str(lit) && m == MutImmutable => {
ExprVstore(e, ExprVstoreSlice)
}
token::AND => {
self.bump();
let _lt = self.parse_opt_lifetime();
let m = self.parse_mutability();
let e = self.parse_prefix_expr();
hi = e.span.hi;
// HACK: turn &[...] into a &-vec
ex = match e.node {
ExprVec(..) if m == MutImmutable => {
ExprVstore(e, ExprVstoreSlice)
}
ExprLit(lit) if lit_is_str(lit) && m == MutImmutable => {
ExprVstore(e, ExprVstoreSlice)
}
ExprVec(..) if m == MutMutable => {
ExprVstore(e, ExprVstoreMutSlice)
}
_ => ExprAddrOf(m, e)
};
ExprVec(..) if m == MutMutable => {
ExprVstore(e, ExprVstoreMutSlice)
}
_ => return self.parse_dot_or_call_expr()
}
_ => ExprAddrOf(m, e)
};
}
token::AT => {
self.bump();
Expand Down Expand Up @@ -2749,10 +2765,10 @@ impl<'a> Parser<'a> {
span: mk_sp(lo, hi)
}
}
token::BINOP(token::AND) => {
token::BINOP(token::AND) | token::ANDAND => {
// parse &pat
let lo = self.span.lo;
self.bump();
self.expect_and();
let sub = self.parse_pat();
hi = sub.span.hi;
// HACK: parse &"..." as a literal of a borrowed str
Expand Down
41 changes: 41 additions & 0 deletions src/test/run-pass/double-ref.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,41 @@
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

fn check_expr() {
let _: & uint = &1u;
let _: & & uint = &&1u;
let _: & & & uint = &&&1u;
let _: & & & uint = & &&1u;
let _: & & & & uint = &&&&1u;
let _: & & & & uint = & &&&1u;
let _: & & & & & uint = &&&&&1u;
}

fn check_ty() {
let _: &uint = & 1u;
let _: &&uint = & & 1u;
let _: &&&uint = & & & 1u;
let _: & &&uint = & & & 1u;
let _: &&&&uint = & & & & 1u;
let _: & &&&uint = & & & & 1u;
let _: &&&&&uint = & & & & & 1u;
}

fn check_pat() {
let &_ = & 1u;
let &&_ = & & 1u;
let &&&_ = & & & 1u;
let & &&_ = & & & 1u;
let &&&&_ = & & & & 1u;
let & &&&_ = & & & & 1u;
let &&&&&_ = & & & & & 1u;
}

pub fn main() {}