Trait FallibleItertools

pub trait FallibleItertools: Itertools {
    // Provided methods
    fn fallible_min_set_by<F, E>(self, compare: F) -> Result<Vec<Self::Item>, E>
       where Self: Sized,
             F: FnMut(&Self::Item, &Self::Item) -> Result<Ordering, E> { ... }
    fn fallible_max_set_by<F, E>(self, compare: F) -> Result<Vec<Self::Item>, E>
       where Self: Sized,
             F: FnMut(&Self::Item, &Self::Item) -> Result<Ordering, E> { ... }
}

A slightly modified version of the Itertools trait which returns Result instead.

Automatically implemented for anything that implements Itertools. This trait is intended for methods which require fallible operations (comparisons, additions etc.). Not all Itertools methods have been ported over. More may be added as needed.

Provided Methods

fn fallible_min_set_by<F, E>(self, compare: F) -> Result<Vec<Self::Item>, E>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Result<Ordering, E>,

Return all minimum elements of an iterator, as determined by the specified function. Or an error if the comparison fails.

Examples

use wagon_utils::FallibleItertools;

let a: [(i32, i32); 0] = [];
assert_eq!(a.iter().fallible_min_set_by(|_, _| Ok::<std::cmp::Ordering, ()>(Ordering::Equal)), Ok(Vec::<&(i32, i32)>::new()));

let a = [(1, 2)];
assert_eq!(a.iter().fallible_min_set_by(|&&(k1,_), &&(k2, _)| Ok::<std::cmp::Ordering, ()>(k1.cmp(&k2))), Ok(vec![&(1, 2)]));

let a = [(1, 2), (2, 2), (3, 9), (4, 8), (5, 9)];
assert_eq!(a.iter().fallible_min_set_by(|&&(_,k1), &&(_,k2)| Err("error")), Err("error"));

let a = [(1, 2), (1, 3), (1, 4), (1, 5)];
assert_eq!(a.iter().fallible_min_set_by(|&&(k1,_), &&(k2, _)| Ok::<std::cmp::Ordering, ()>(k1.cmp(&k2))), Ok(vec![&(1, 2), &(1, 3), &(1, 4), &(1, 5)]));

The elements can be floats but no particular result is guaranteed if an element is NaN.

Errors

Returns an error if the comparison function returns an error at any point.

fn fallible_max_set_by<F, E>(self, compare: F) -> Result<Vec<Self::Item>, E>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Result<Ordering, E>,

Return all maximum elements of an iterator, as determined by the specified function.

Examples

use wagon_utils::FallibleItertools;

let a: [(i32, i32); 0] = [];
assert_eq!(a.iter().fallible_max_set_by(|_, _| Ok::<std::cmp::Ordering, ()>(Ordering::Equal)), Ok(Vec::<&(i32, i32)>::new()));

let a = [(1, 2)];
assert_eq!(a.iter().fallible_max_set_by(|&&(k1,_), &&(k2, _)| Ok::<std::cmp::Ordering, ()>(k1.cmp(&k2))), Ok(vec![&(1, 2)]));

let a = [(1, 2), (2, 2), (3, 9), (4, 8), (5, 9)];
assert_eq!(a.iter().fallible_max_set_by(|&&(_,k1), &&(_,k2)| Err("error")), Err("error"));

let a = [(1, 2), (1, 3), (1, 4), (1, 5)];
assert_eq!(a.iter().fallible_max_set_by(|&&(k1,_), &&(k2, _)| Ok::<std::cmp::Ordering, ()>(k1.cmp(&k2))), Ok(vec![&(1, 2), &(1, 3), &(1, 4), &(1, 5)]));

The elements can be floats but no particular result is guaranteed if an element is NaN.

Errors

Returns an error if the comparison function returns an error at any point.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T> FallibleItertools for T

where T: Itertools,