| // Copyright 2012 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. |
| |
| use syntax::ext::base::ExtCtxt; |
| use syntax::ext::base; |
| use syntax::feature_gate; |
| use syntax::parse::token::keywords; |
| use syntax_pos::Span; |
| use syntax::tokenstream::TokenTree; |
| |
| pub fn expand_trace_macros(cx: &mut ExtCtxt, |
| sp: Span, |
| tt: &[TokenTree]) |
| -> Box<base::MacResult+'static> { |
| if !cx.ecfg.enable_trace_macros() { |
| feature_gate::emit_feature_err(&cx.parse_sess.span_diagnostic, |
| "trace_macros", |
| sp, |
| feature_gate::GateIssue::Language, |
| feature_gate::EXPLAIN_TRACE_MACROS); |
| return base::DummyResult::any(sp); |
| } |
| |
| match (tt.len(), tt.first()) { |
| (1, Some(&TokenTree::Token(_, ref tok))) if tok.is_keyword(keywords::True) => { |
| cx.set_trace_macros(true); |
| } |
| (1, Some(&TokenTree::Token(_, ref tok))) if tok.is_keyword(keywords::False) => { |
| cx.set_trace_macros(false); |
| } |
| _ => cx.span_err(sp, "trace_macros! accepts only `true` or `false`"), |
| } |
| |
| base::DummyResult::any(sp) |
| } |