72 lines
2.3 KiB
Rust
72 lines
2.3 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 ast;
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use codemap::Span;
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use ext::base::*;
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use ext::base;
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use feature_gate;
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use parse::token;
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use parse::token::str_to_ident;
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use ptr::P;
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pub fn expand_syntax_ext<'cx>(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
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-> Box<base::MacResult+'cx> {
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if !cx.ecfg.enable_concat_idents() {
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feature_gate::emit_feature_err(&cx.parse_sess.span_diagnostic,
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"concat_idents",
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sp,
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feature_gate::EXPLAIN_CONCAT_IDENTS);
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return base::DummyResult::expr(sp);
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}
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let mut res_str = String::new();
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for (i, e) in tts.iter().enumerate() {
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if i & 1 == 1 {
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match *e {
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ast::TtToken(_, token::Comma) => {},
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_ => {
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cx.span_err(sp, "concat_idents! expecting comma.");
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return DummyResult::expr(sp);
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},
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}
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} else {
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match *e {
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ast::TtToken(_, token::Ident(ident, _)) => {
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res_str.push_str(&token::get_ident(ident))
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},
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_ => {
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cx.span_err(sp, "concat_idents! requires ident args.");
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return DummyResult::expr(sp);
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},
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}
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}
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}
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let res = str_to_ident(&res_str[..]);
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let e = P(ast::Expr {
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id: ast::DUMMY_NODE_ID,
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node: ast::ExprPath(None,
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ast::Path {
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span: sp,
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global: false,
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segments: vec!(
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ast::PathSegment {
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identifier: res,
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parameters: ast::PathParameters::none(),
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}
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)
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}
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),
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span: sp,
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});
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MacEager::expr(e)
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}
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