syntax: allow stmt/expr macro invocations to be delimited by {}.
This makes using control-flow-y macros like `spawn! { ... }` more fluent and natural. cc #11892.
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@ -3185,15 +3185,35 @@ impl Parser {
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let pth = self.parse_path(NoTypesAllowed).path;
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self.bump();
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let id = if self.token == token::LPAREN {
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let id = if self.token == token::LPAREN || self.token == token::LBRACE {
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token::special_idents::invalid // no special identifier
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} else {
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self.parse_ident()
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};
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// check that we're pointing at delimiters (need to check
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// again after the `if`, because of `parse_ident`
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// consuming more tokens).
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let (bra, ket) = match self.token {
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token::LPAREN => (token::LPAREN, token::RPAREN),
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token::LBRACE => (token::LBRACE, token::RBRACE),
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_ => {
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// we only expect an ident if we didn't parse one
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// above.
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let ident_str = if id == token::special_idents::invalid {
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"identifier, "
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} else {
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""
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};
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let tok_str = self.this_token_to_str();
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self.fatal(format!("expected {}`(` or `\\{`, but found `{}`",
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ident_str, tok_str))
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}
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};
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let tts = self.parse_unspanned_seq(
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&token::LPAREN,
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&token::RPAREN,
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&bra,
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&ket,
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seq_sep_none(),
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|p| p.parse_token_tree()
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);
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@ -0,0 +1,13 @@
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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fn main() {
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foo! bar < //~ ERROR expected `(` or `{`, but found `<`
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}
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@ -0,0 +1,15 @@
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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fn main() {
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foo! {
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bar, "baz", 1, 2.0
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) //~ ERROR incorrect close delimiter
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}
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@ -0,0 +1,15 @@
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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fn main() {
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foo! (
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bar, "baz", 1, 2.0
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} //~ ERROR incorrect close delimiter
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}
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@ -0,0 +1,28 @@
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#[feature(macro_rules)];
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macro_rules! expr (($e: expr) => { $e })
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macro_rules! spawn {
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($($code: tt)*) => {
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expr!(spawn(proc() {$($code)*}))
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}
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}
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pub fn main() {
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spawn! {
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info!("stmt");
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};
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let _ = spawn! {
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info!("expr");
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};
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}
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