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//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
//
//! Map implementation.
//!
//! Will be automatically included when including `filter::Filter`, so importing this module
//! shouldn't be necessary.
//!
use std::borrow::Borrow;
use std::marker::PhantomData;
use crate::failable::filter::FailableFilter;
#[must_use = "filters are lazy and do nothing unless consumed"]
#[derive(Clone)]
pub struct FailableMapInput<F, M, FT, B>(F, M, PhantomData<FT>, PhantomData<B>);
impl<F, M, FT, B> FailableMapInput<F, M, FT, B> {
pub fn new(a: F, m: M) -> FailableMapInput<F, M, FT, B> {
FailableMapInput(a, m, PhantomData, PhantomData)
}
}
impl<FT, F, T, B, M> FailableFilter<T> for FailableMapInput<F, M, FT, B>
where
F: FailableFilter<FT>,
B: Borrow<FT> + Sized,
M: Fn(&T) -> B,
{
type Error = F::Error;
fn filter(&self, e: &T) -> Result<bool, Self::Error> {
self.0.filter(self.1(e).borrow())
}
}
#[must_use = "filters are lazy and do nothing unless consumed"]
#[derive(Clone)]
pub struct FailableMapErr<F, M, E>(F, M, PhantomData<E>);
impl<F, M, E> FailableMapErr<F, M, E> {
pub fn new(a: F, m: M) -> FailableMapErr<F, M, E> {
FailableMapErr(a, m, PhantomData)
}
}
impl<E, F, T, M> FailableFilter<T> for FailableMapErr<F, M, E>
where
F: FailableFilter<T>,
M: Fn(F::Error) -> E,
{
type Error = E;
fn filter(&self, e: &T) -> Result<bool, Self::Error> {
self.0.filter(e).map_err(&self.1)
}
}
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