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use crate::{
repetition_parser::{
RepetitionParserError,
RepetitionParserRequirement,
},
Parser,
};
use std::marker::PhantomData;
#[derive(Debug)]
pub struct RepetitionParser<'a, P>
where
P: Parser<'a>,
{
requirement: P,
min: usize,
max: usize,
_a: PhantomData<&'a ()>,
}
impl<'a, P> RepetitionParser<'a, P>
where
P: Parser<'a>,
{
pub fn new(requirement: P, min: usize, max: usize) -> Self
{
Self {
requirement,
min,
max,
_a: PhantomData,
}
}
}
impl<'a, P> Parser<'a> for RepetitionParser<'a, P>
where
P: Parser<'a>,
{
type Error = RepetitionParserError<'a, P>;
type Output = Vec<P::Output>;
type Requirement = RepetitionParserRequirement<'a, P>;
type RequirementContext = ();
fn parse(&self, src: &'a str, pos: &mut usize) -> Result<Self::Output, Self::Error>
{
let from = *pos;
let mut result = vec![];
for i in 0..self.min
{
let res: <P as Parser>::Output = self.requirement.parse(src, pos).map_err(|err| {
*pos = from;
RepetitionParserError::new(from, self.requirement(None), i, err)
})?;
result.push(res)
}
for _ in self.min..self.max
{
if let Ok(res) = self.requirement.parse(src, pos)
{
result.push(res)
}
else
{
break;
}
}
Ok(result)
}
fn skip(&self, src: &'a str, pos: &mut usize) -> Result<(), Self::Error>
{
let from = *pos;
for i in 0..self.min
{
if let Err(err) = self.requirement.parse(src, pos)
{
*pos = from;
return Err(RepetitionParserError::new(
from,
self.requirement(None),
i,
err,
));
}
}
for _ in self.min..self.max
{
if let Err(_) = self.requirement.parse(src, pos)
{
break;
}
}
Ok(())
}
fn requirement(&self, _: Option<&Self::RequirementContext>) -> Self::Requirement
{
RepetitionParserRequirement::new(self.requirement.requirement(None), self.min, self.max)
}
}