1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
4 //
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
10
11 use ast;
12 use codemap::Span;
13 use ext::base::*;
14 use ext::base;
15 use owned_slice::OwnedSlice;
16 use parse::token;
17 use parse::token::{str_to_ident};
18
19 use std::strbuf::StrBuf;
20
21 pub fn expand_syntax_ext(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
22 -> Box<base::MacResult> {
23 let mut res_str = StrBuf::new();
24 for (i, e) in tts.iter().enumerate() {
25 if i & 1 == 1 {
26 match *e {
27 ast::TTTok(_, token::COMMA) => (),
28 _ => {
29 cx.span_err(sp, "concat_idents! expecting comma.");
30 return DummyResult::expr(sp);
31 }
32 }
33 } else {
34 match *e {
35 ast::TTTok(_, token::IDENT(ident,_)) => {
36 res_str.push_str(token::get_ident(ident).get())
37 }
38 _ => {
39 cx.span_err(sp, "concat_idents! requires ident args.");
40 return DummyResult::expr(sp);
41 }
42 }
43 }
44 }
45 let res = str_to_ident(res_str.into_owned());
46
47 let e = @ast::Expr {
48 id: ast::DUMMY_NODE_ID,
49 node: ast::ExprPath(
50 ast::Path {
51 span: sp,
52 global: false,
53 segments: vec!(
54 ast::PathSegment {
55 identifier: res,
56 lifetimes: Vec::new(),
57 types: OwnedSlice::empty(),
58 }
59 )
60 }
61 ),
62 span: sp,
63 };
64 MacExpr::new(e)
65 }