RosettaCodeData/Task/Permutations/Sidef/permutations-3.sidef

func permutations(callback, set, perm=[]) {
    set || callback(perm)
    for i in ^set {
        __FUNC__(callback, [
            set[^i, i+1 ..^ set.len]
        ], [perm..., set[i]])
    }
    return()
}

permutations({|p| say p }, [0,1,2])