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use crate::{
map_parser::{
MapParserError,
MapParserRequirement,
},
Parser,
};
use std::fmt::{
Debug,
Formatter,
Result as FmtResult,
};
pub struct MapParser<'a, P, R>
where
P: 'a + Parser<'a>,
{
requirement: P,
mapper: &'a Fn(P::Output) -> R,
}
impl<'a, P, R> MapParser<'a, P, R>
where
P: Parser<'a>,
{
pub fn new(requirement: P, mapper: &'a Fn(P::Output) -> R) -> Self
{
Self {
requirement,
mapper,
}
}
}
impl<'a, P, R> Debug for MapParser<'a, P, R>
where
P: Parser<'a>,
{
fn fmt(&self, f: &mut Formatter) -> FmtResult
{
f.debug_struct("MapParser")
.field("requirement", &self.requirement)
.field("mapper", &"..")
.finish()
}
}
impl<'a, P, R> Parser<'a> for MapParser<'a, P, R>
where
P: Parser<'a>,
{
type Error = MapParserError<'a, P>;
type Output = R;
type Requirement = MapParserRequirement<'a, P>;
type RequirementContext = ();
fn parse(&self, src: &'a str, pos: &mut usize) -> Result<Self::Output, Self::Error>
{
let from = *pos;
self.requirement
.parse(src, pos)
.map(|res| (self.mapper)(res))
.map_err(|err| MapParserError::new(from, self.requirement(None), err))
}
fn skip(&self, src: &'a str, pos: &mut usize) -> Result<(), Self::Error>
{
let from = *pos;
self.requirement
.skip(src, pos)
.map_err(|err| MapParserError::new(from, self.requirement(None), err))
}
fn requirement(&self, _: Option<&Self::RequirementContext>) -> Self::Requirement
{
MapParserRequirement::new(self.requirement.requirement(None))
}
}
#[test]
fn test()
{
use crate::string;
let parser = string("test");
let parser = parser.map(&|s| s.to_owned());
let src = "test";
let mut pos = 0;
let res = parser.parse(src, &mut pos);
}