Function `try_range`

fn try_range<R>(range: R, bounds: RangeTo<usize>) -> Option<Range<usize>>
where
    R: RangeBounds<usize>

Performs bounds checking of a range without panicking.

This is a version of [range()] that returns None instead of panicking.

Examples

#![feature(slice_range)]

use std::slice;

let v = [10, 40, 30];
assert_eq!(Some(1..2), slice::try_range(1..2, ..v.len()));
assert_eq!(Some(0..2), slice::try_range(..2, ..v.len()));
assert_eq!(Some(1..3), slice::try_range(1.., ..v.len()));

Returns None when Index::index would panic:

#![feature(slice_range)]

use std::slice;

assert_eq!(None, slice::try_range(2..1, ..3));
assert_eq!(None, slice::try_range(1..4, ..3));
assert_eq!(None, slice::try_range(1..=usize::MAX, ..3));