pattern_matching.roga

module PatternMatching { head, tail, pairs, transform }

let head [h :: _] = h
let tail [_ :: t] = t

let transform {1, 2, 3} = ^got_123
let transform {a, 0, c} = {a, ^zero, c}
let transform {0, b, c} = {b, b * c, c}
let transform {a, b, 0} = {a, a * b, b}

let pairs n =
  n
  |> range
  |> map (x -> {x, x * x, x * (x * x)})
  |> map ^transform