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use std::rc::Rc;
use parsers::{Parser, ParserCombinator, ParseResult};
pub type SliceParser<I,O> = Parser<I=[I], O=O>;
pub fn lit<T: Eq + Clone>(l: T) -> LiteralParser<T> {
LiteralParser{literal: l}
}
pub fn matcher<T: Clone, U, F: 'static + Fn(T) -> Option<U>>(f: F) -> MatchParser<T, U> {
MatchParser{matcher: Rc::new(Box::new(f))}
}
#[derive(Clone)]
pub struct LiteralParser< T: Eq + Clone> {
pub literal: T,
}
impl<T: Eq + Clone> Parser for LiteralParser< T> {
type I = [T];
type O = T;
fn parse<'a>(&self, data: &'a [T]) -> ParseResult<&'a [T], T> {
if data.len() < 1 {
return Err(format!("ran out of data"))
}
if data[0] == self.literal {
Ok((data[0].clone(), &data[1..]))
} else {
Err(format!("Literal mismatch"))
}
}
}
impl<T: Eq + Clone> ParserCombinator for LiteralParser<T>{}
pub struct MatchParser<T: Clone, U> {
matcher: Rc<Box<Fn(T) -> Option<U>>>
}
impl<T: Clone, U> Parser for MatchParser<T,U> {
type I = [T];
type O = U;
fn parse<'a>(&self, data: &'a [T]) -> ParseResult<&'a [T], Self::O> {
if data.len() < 1 {
return Err(format!("ran out of data"))
}
match (self.matcher)(data[0].clone()) {
Some(u) => Ok((u, &data[1..])),
None => Err(format!("Match failed"))
}
}
}
impl<T: Clone, U> ParserCombinator for MatchParser<T,U> {}
impl<T: Clone, U> Clone for MatchParser<T,U> {
fn clone(&self) -> Self {
MatchParser{matcher: self.matcher.clone()}
}
}