rust/src/libsyntax/ext/concat_idents.rs

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// 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 core::prelude::*;
use ext::base::*;
use ext::base;
fn expand_syntax_ext(cx: ext_ctxt, sp: span, tts: ~[ast::token_tree])
-> base::mac_result {
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let mut res_str = ~"";
for tts.eachi |i, e| {
if i & 1 == 1 {
match *e {
ast::tt_tok(_, token::COMMA) => (),
_ => cx.span_fatal(sp, ~"concat_idents! \
expecting comma.")
}
} else {
match *e {
ast::tt_tok(_, token::IDENT(ident,_)) =>
res_str += cx.str_of(ident),
_ => cx.span_fatal(sp, ~"concat_idents! \
requires ident args.")
}
}
}
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let res = cx.parse_sess().interner.intern(@res_str);
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let e = @ast::expr {
id: cx.next_id(),
callee_id: cx.next_id(),
node: ast::expr_path(
@ast::path {
span: sp,
global: false,
idents: ~[res],
rp: None,
types: ~[],
}
),
span: sp,
};
mr_expr(e)
}