// 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::ptr::P; use syntax_pos::Span; use syntax_pos::symbol::Symbol; use syntax_pos::hygiene::SyntaxContext; 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, "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 = ast::Ident { name: Symbol::intern(&res_str), ctxt: SyntaxContext::empty().apply_mark(cx.current_expansion.mark), }; struct Result { ident: ast::Ident, span: Span, }; impl Result { fn path(&self) -> ast::Path { ast::Path { span: self.span, segments: vec![ast::PathSegment::from_ident(self.ident, self.span)], } } } 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, }) }