CodeIQとかで"module Str"を使ったsplitが使えないので、自前で何とかsplitするやつを書く ref: http://qiita.com/esehara@github/items/894d8dd824b1354752f5

file0.ml

 Str.split (Str.regexp_string ",") line

file1.ml

let string_separate s c = 
  let rec s_separate s c p =
    let next_separate s p c =
      try
        (String.index_from s (p + 1) c)
      with _ -> String.length s in
    let start = p in
    let next  = next_separate s p c in
    [String.sub s start (next - start)] @
      (if next < String.length s then s_separate s c (next + 1)
       else []) in
  s_separate s c 0;;