isPermutationOf

assert([1, 2, 3, 4, 5].s[].isPermutationOf([1, 2, 4, 5, 3].s[]));
assert(![1, 2, 3, 4, 5].s[].isPermutationOf([1, 4, 5, 3].s[]));

assert(!``w.isAnagramOf(``));
assert(`äöå`w.isAnagramOf(`åäö`));
assert(`äöå`.isAnagramOf(`åäö`w));
assert(`äöå`w.isAnagramOf(`åäö`w));

assert(`äöå`d.isAnagramOf(`åäö`));
assert(`äöå`.isAnagramOf(`åäö`d));
assert(`äöå`d.isAnagramOf(`åäö`d));

assert(`äöå`.isAnagramOf(`åäö`));
assert(!`äöå`.isAnagramOf(`xyz`));
assert(!`äöå`.isAnagramOf(``));
assert(!``.isAnagramOf(`åäö`));

import std.conv: to;

auto x = `äöå`.to!(dchar[]);

auto y = sort(x);
alias Y = typeof(y);

immutable z = `åäö`;

assert(y.isAnagramOf(z));
assert(z.isAnagramOf(y));