Run-Length Encoding in OCaml

rle.ml

(*
This is a simple solution to the Run-Length Encoding problem described
in Watrophy #24 (http://www.watrophy.com/posts/24-Run-Length-Encoding.html)
*)

open Core

let rle int_list =
  let increment tup n =
    match tup with
    | (k, v) -> if k = n then [(k, v+1)] else [(n, 1); (k,v)]  in
  let increment_if_match accum n =
    match List.rev accum with
    | [] -> [(n, 1)]
    | hd :: tl -> List.rev ( (increment hd n) @ tl ) in
  List.fold_left int_list ~init:[] ~f:increment_if_match