oak 0.8.0

A typed parser generator syntax extension for Parsing Expression Grammar (PEG).
Documentation 
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// Copyright 2016 Pierre Talbot (IRCAM)

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use back::compiler::*;

type MatchPatternFn = for <'a> fn(&mut Context<'a>) -> syn::Pat;

fn ignore_value<'a>(_context: &mut Context<'a>) -> syn::Pat {
  parse_quote!(_)
}

fn bind_value<'a>(context: &mut Context<'a>) -> syn::Pat {
  let var = context.next_free_var();
  parse_quote!(#var)
}

pub struct AnySingleCharCompiler
{
  matched_pattern: MatchPatternFn
}

impl AnySingleCharCompiler
{
  pub fn recognizer() -> AnySingleCharCompiler {
    AnySingleCharCompiler {
      matched_pattern: ignore_value
    }
  }

  pub fn parser() -> AnySingleCharCompiler {
    AnySingleCharCompiler {
      matched_pattern: bind_value
    }
  }
}

impl CompileExpr for AnySingleCharCompiler
{
  fn compile_expr<'a>(&self, context: &mut Context<'a>,
    continuation: Continuation) -> syn::Expr
  {
    let pattern = (self.matched_pattern)(context);
    continuation
      .map_success(|success, failure| parse_quote!(
        match state.next() {
          Some(#pattern) => {
            #success
          }
          None => {
            state.error("<character>");
            #failure
          }
        }
      ))
     .unwrap_success()
  }
}