src/test/auxiliary/plugin_args.rs

   1 // Copyright 2015 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 // force-host
  12
  13 #![feature(plugin_registrar)]
  14 #![feature(box_syntax)]
  15
  16 extern crate syntax;
  17 extern crate rustc;
  18
  19 use std::borrow::ToOwned;
  20 use syntax::ast;
  21 use syntax::codemap::Span;
  22 use syntax::ext::build::AstBuilder;
  23 use syntax::ext::base::{TTMacroExpander, ExtCtxt, MacResult, MacExpr, NormalTT};
  24 use syntax::parse::token;
  25 use syntax::print::pprust;
  26 use syntax::ptr::P;
  27 use rustc::plugin::Registry;
  28
  29 struct Expander {
  30     args: P<ast::MetaItem>,
  31 }
  32
  33 impl TTMacroExpander for Expander {
  34     fn expand<'cx>(&self,
  35                    ecx: &'cx mut ExtCtxt,
  36                    sp: Span,
  37                    _: &[ast::TokenTree]) -> Box<MacResult+'cx> {
  38
  39         let attr = ecx.attribute(sp, self.args.clone());
  40         let src = pprust::attribute_to_string(&attr);
  41         let interned = token::intern_and_get_ident(src.as_slice());
  42         MacExpr::new(ecx.expr_str(sp, interned))
  43     }
  44 }
  45
  46 #[plugin_registrar]
  47 pub fn plugin_registrar(reg: &mut Registry) {
  48     let args = reg.args().clone();
  49     reg.register_syntax_extension(token::intern("plugin_args"),
  50         NormalTT(box Expander { args: args, }, None));
  51 }