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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 syntax::ast;
use syntax::ext::base::*;
use syntax::ext::base;
use syntax::feature_gate;
use syntax::parse::token;
use syntax::parse::token::str_to_ident;
use syntax::ptr::P;
use syntax_pos::Span;
use syntax::tokenstream::TokenTree;
pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[TokenTree])
-> Box<base::MacResult+'cx> {
if !cx.ecfg.enable_concat_idents() {
feature_gate::emit_feature_err(&cx.parse_sess.span_diagnostic,
"concat_idents",
sp,
feature_gate::GateIssue::Language,
feature_gate::EXPLAIN_CONCAT_IDENTS);
return base::DummyResult::expr(sp);
}
let mut res_str = String::new();
for (i, e) in tts.iter().enumerate() {
if i & 1 == 1 {
match *e {
TokenTree::Token(_, token::Comma) => {},
_ => {
cx.span_err(sp, "concat_idents! expecting comma.");
return DummyResult::expr(sp);
},
}
} else {
match *e {
TokenTree::Token(_, token::Ident(ident)) => {
res_str.push_str(&ident.name.as_str())
},
_ => {
cx.span_err(sp, "concat_idents! requires ident args.");
return DummyResult::expr(sp);
},
}
}
}
let res = str_to_ident(&res_str);
struct Result { ident: ast::Ident, span: Span };
impl Result {
fn path(&self) -> ast::Path {
let segment = ast::PathSegment {
identifier: self.ident,
parameters: ast::PathParameters::none()
};
ast::Path { span: self.span, global: false, segments: vec![segment] }
}
}
impl base::MacResult for Result {
fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
Some(P(ast::Expr {
id: ast::DUMMY_NODE_ID,
node: ast::ExprKind::Path(None, self.path()),
span: self.span,
attrs: ast::ThinVec::new(),
}))
}
fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
Some(P(ast::Ty {
id: ast::DUMMY_NODE_ID,
node: ast::TyKind::Path(None, self.path()),
span: self.span,
}))
}
}
Box::new(Result { ident: res, span: sp })
}
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