w3_6.1_advanced_patterns.ml

type e = EInt of int | EMul of e * e | EAdd of e * e

let simplify = function
  | EMul (e, EInt 0) | EMul (EInt 0, e) -> EInt 0
  | EMul (e, EInt 1) | EMul (EInt 1, e)
  | EAdd (e, EInt 0) | EAdd (EInt 0, e)
  | e -> e;;

let only_small_lists = function
  | ([_] | [_;_]) as l -> l
  | _ -> [];;

let rec no_consecutive_repetition = function
  | x :: y :: ys when x = y -> no_consecutive_repetition (y :: ys)
  | x :: y :: ys -> x :: no_consecutive_repetition (y :: ys)
  | l -> l;;