rust/src/libsyntax/ext/trace_macros.rs
2013-07-17 14:57:51 -07:00

45 lines
1.5 KiB
Rust

// 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 ast;
use codemap::span;
use ext::base::ExtCtxt;
use ext::base;
use parse::lexer::{new_tt_reader, reader};
use parse::parser::Parser;
use parse::token::keywords;
pub fn expand_trace_macros(cx: @ExtCtxt,
sp: span,
tt: &[ast::token_tree])
-> base::MacResult {
let sess = cx.parse_sess();
let cfg = cx.cfg();
let tt_rdr = new_tt_reader(cx.parse_sess().span_diagnostic,
None,
tt.to_owned());
let rdr = tt_rdr as @reader;
let rust_parser = Parser(sess, cfg.clone(), rdr.dup());
if rust_parser.is_keyword(keywords::True) {
cx.set_trace_macros(true);
} else if rust_parser.is_keyword(keywords::False) {
cx.set_trace_macros(false);
} else {
cx.span_fatal(sp, "trace_macros! only accepts `true` or `false`")
}
rust_parser.bump();
let rust_parser = Parser(sess, cfg, rdr.dup());
let result = rust_parser.parse_expr();
base::MRExpr(result)
}