43 lines
1.6 KiB
Rust
43 lines
1.6 KiB
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 syntax::ext::base::ExtCtxt;
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use syntax::ext::base;
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use syntax::feature_gate;
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use syntax::symbol::keywords;
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use syntax_pos::Span;
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use syntax::tokenstream::TokenTree;
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pub fn expand_trace_macros(cx: &mut ExtCtxt,
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sp: Span,
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tt: &[TokenTree])
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-> Box<base::MacResult + 'static> {
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if !cx.ecfg.enable_trace_macros() {
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feature_gate::emit_feature_err(&cx.parse_sess,
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"trace_macros",
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sp,
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feature_gate::GateIssue::Language,
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feature_gate::EXPLAIN_TRACE_MACROS);
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return base::DummyResult::any(sp);
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}
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match (tt.len(), tt.first()) {
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(1, Some(&TokenTree::Token(_, ref tok))) if tok.is_keyword(keywords::True) => {
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cx.set_trace_macros(true);
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}
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(1, Some(&TokenTree::Token(_, ref tok))) if tok.is_keyword(keywords::False) => {
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cx.set_trace_macros(false);
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}
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_ => cx.span_err(sp, "trace_macros! accepts only `true` or `false`"),
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}
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base::DummyResult::any(sp)
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}
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