src/test/ui-fulldeps/auxiliary/plugin-args.rs

   1 // force-host
   2
   3 #![feature(plugin_registrar)]
   4 #![feature(box_syntax, rustc_private)]
   5
   6 extern crate syntax;
   7 extern crate syntax_pos;
   8 extern crate rustc;
   9 extern crate rustc_plugin;
  10 extern crate rustc_driver;
  11
  12 use std::borrow::ToOwned;
  13 use syntax::ast;
  14 use syntax::ext::base::{SyntaxExtension, SyntaxExtensionKind};
  15 use syntax::ext::base::{TTMacroExpander, ExtCtxt, MacResult, MacEager};
  16 use syntax::print::pprust;
  17 use syntax::symbol::Symbol;
  18 use syntax_pos::Span;
  19 use syntax::tokenstream::TokenStream;
  20 use rustc_plugin::Registry;
  21
  22 struct Expander {
  23     args: Vec<ast::NestedMetaItem>,
  24 }
  25
  26 impl TTMacroExpander for Expander {
  27     fn expand<'cx>(&self,
  28                    ecx: &'cx mut ExtCtxt,
  29                    sp: Span,
  30                    _: TokenStream) -> Box<dyn MacResult+'cx> {
  31         let args = self.args.iter().map(|i| pprust::meta_list_item_to_string(i))
  32             .collect::<Vec<_>>().join(", ");
  33         MacEager::expr(ecx.expr_str(sp, Symbol::intern(&args)))
  34     }
  35 }
  36
  37 #[plugin_registrar]
  38 pub fn plugin_registrar(reg: &mut Registry) {
  39     let args = reg.args().to_owned();
  40     reg.register_syntax_extension(Symbol::intern("plugin_args"), SyntaxExtension::default(
  41         SyntaxExtensionKind::LegacyBang(Box::new(Expander { args })), reg.sess.edition()
  42     ));
  43 }