makeIndex

import mir.algorithm.iteration: all;
import mir.ndslice.topology: indexed, pairwise;

immutable arr = [ 2, 3, 1, 5, 0 ];
auto index = arr.makeIndex;

assert(arr.indexed(index).pairwise!"a < b".all);

import mir.algorithm.iteration: equal;
import mir.ndslice.topology: indexed;

immutable arr0 = [ 2, 3, 1, 5,  0 ];
immutable arr1 = [ 1, 5, 4, 2, -1 ];

auto index = makeIndex(arr0);
assert(index.equal([4, 2, 0, 1, 3]));
auto view = arr1.indexed(index);
assert(view.equal([-1, 4, 1, 5, 2]));