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// Copyright 2015 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.
// force-host
#![crate_type="dylib"]
#![feature(plugin_registrar, quote)]
extern crate syntax;
extern crate rustc;
use syntax::codemap::Span;
use syntax::parse::token::{self, str_to_ident, NtExpr, NtPat};
use syntax::ast::{TokenTree, TtToken, Pat};
use syntax::ext::base::{ExtCtxt, MacResult, DummyResult, MacEager};
use syntax::ext::build::AstBuilder;
use syntax::ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
use syntax::ext::tt::macro_parser::{Success, Failure, Error};
use syntax::ptr::P;
use rustc::plugin::Registry;
fn expand_mbe_matches(cx: &mut ExtCtxt, sp: Span, args: &[TokenTree])
-> Box<MacResult + 'static> {
let mbe_matcher = quote_matcher!(cx, $matched:expr, $($pat:pat)|+);
let mac_expr = match TokenTree::parse(cx, &mbe_matcher[..], args) {
Success(map) => {
match (&*map[str_to_ident("matched")], &*map[str_to_ident("pat")]) {
(&MatchedNonterminal(NtExpr(ref matched_expr)),
&MatchedSeq(ref pats, seq_sp)) => {
let pats: Vec<P<Pat>> = pats.iter().map(|pat_nt|
if let &MatchedNonterminal(NtPat(ref pat)) = &**pat_nt {
pat.clone()
} else {
unreachable!()
}
).collect();
let arm = cx.arm(seq_sp, pats, cx.expr_bool(seq_sp, true));
quote_expr!(cx,
match $matched_expr {
$arm
_ => false
}
)
}
_ => unreachable!()
}
}
Failure(_, s) | Error(_, s) => {
panic!("expected Success, but got Error/Failure: {}", s);
}
};
MacEager::expr(mac_expr)
}
#[plugin_registrar]
pub fn plugin_registrar(reg: &mut Registry) {
reg.register_macro("matches", expand_mbe_matches);
}
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