86 lines
2.9 KiB
Rust
86 lines
2.9 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 syntax::ast;
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use syntax::ext::base::*;
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use syntax::ext::base;
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use syntax::feature_gate;
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use syntax::parse::token;
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use syntax::ptr::P;
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use syntax_pos::Span;
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use syntax_pos::symbol::Symbol;
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use syntax::tokenstream::TokenTree;
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pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt,
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sp: Span,
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tts: &[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,
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"concat_idents",
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sp,
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feature_gate::GateIssue::Language,
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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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if tts.is_empty() {
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cx.span_err(sp, "concat_idents! takes 1 or more arguments.");
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return 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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TokenTree::Token(_, 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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TokenTree::Token(_, token::Ident(ident, _)) =>
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res_str.push_str(&ident.name.as_str()),
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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 ident = ast::Ident::new(Symbol::intern(&res_str), sp.apply_mark(cx.current_expansion.mark));
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struct ConcatIdentsResult { ident: ast::Ident }
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impl base::MacResult for ConcatIdentsResult {
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fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
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Some(P(ast::Expr {
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id: ast::DUMMY_NODE_ID,
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node: ast::ExprKind::Path(None, ast::Path::from_ident(self.ident)),
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span: self.ident.span,
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attrs: ast::ThinVec::new(),
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}))
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}
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fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
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Some(P(ast::Ty {
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id: ast::DUMMY_NODE_ID,
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node: ast::TyKind::Path(None, ast::Path::from_ident(self.ident)),
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span: self.ident.span,
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}))
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}
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}
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Box::new(ConcatIdentsResult { ident })
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}
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