Given a string, separate it into groups of non-space equal characters, sorted.

explode_string.ml

open Base
open Stdio

let explode_string str =
  String.to_list str
  |> List.filter ~f:(fun c -> not (phys_equal c ' '))
  |> List.sort_and_group ~compare:(fun a b -> Char.compare a b)
  |> List.map ~f:(fun l -> String.of_char_list l)

let%expect_test "explode_string 1" =
  let res = explode_string "Ahh, abracadabra!" in
  List.iter res ~f:(fun str -> print_string str);
  [%expect {|!,Aaaaaabbcdhhrr|}]

let%expect_test "explode_string 2" =
  let res = explode_string "\\o/\\o/" in
  List.iter res ~f:(fun str -> print_string str);
  [%expect {|//\\oo|}]