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Huon Wilson
cda33346d0
Previously
trace_macros!(true)
fn main() {}
would complain about `trace_macros` being an expression macro in item
position. This is a pointless limitation, because the macro is purely
compile-time, with no runtime effect. (And similarly for log_syntax.)
This also changes the behaviour of `trace_macros!` very slightly, it
used to be equivalent to
macro_rules! trace_macros {
(true $($_x: tt)*) => { true };
(false $($_x: tt)*) => { false }
}
I.e. you could invoke it with arbitrary trailing arguments, which were
ignored. It is changed to accept only exactly `true` or `false` (with no
trailing arguments) and expands to `()`.
28 lines
961 B
Rust
28 lines
961 B
Rust
// Copyright 2012 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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use ast;
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use codemap;
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use ext::base;
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use print;
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pub fn expand_syntax_ext(cx: &mut base::ExtCtxt,
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sp: codemap::Span,
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tt: &[ast::TokenTree])
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-> base::MacResult {
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cx.print_backtrace();
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println!("{}", print::pprust::tt_to_str(&ast::TTDelim(
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@tt.iter().map(|x| (*x).clone()).collect())));
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// any so that `log_syntax` can be invoked as an expression and item.
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base::MacResult::dummy_any(sp)
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}
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