List Ops

class ListOps {

static append(list1, list2) {
    list1+list2
}

static concatenate(lists) {
    lists.collectMany{ it }
}

static filter(list, fn) {
    list.findAll fn
}

static length(list) {
    list.size()
}

static map(list, fn) {
    list.collect fn
}

static foldl(list, fn, initial) {
    list.inject(initial, {acc, elm-> fn(acc,elm)})
}

static foldr(list, fn, initial) {
    list.reverse().inject(initial, {acc, elm-> fn(acc,elm)})
}


static reverse(list) {
    list.reverse()
}

}