OCaml version

rangemerge.ml

(*
 * ocamlfind ocamlc -package containers -linkpkg rangemerge.ml
 *)
open Containers
open Printf

let normalize_range ranges =
  List.sort (fun x y -> compare (fst x) (fst y)) ranges
  |> List.fold_left (fun acc x ->
      let src = List.hd acc in
      if fst x >= fst src && fst x <= snd src then
        (fst src, max (snd src) (snd x)) :: List.tl acc
      else x::acc) [List.hd ranges]
  |> List.rev

let parse_range line =
  String.split "," line
  |> List.map (fun arange ->
      let pair = List.map (fun s -> String.trim s) (String.split "-" arange) in
      if List.length pair = 1 then
        let value = int_of_string (List.hd pair) in (value, value)
      else
        (int_of_string (List.hd pair), int_of_string (List.nth pair 1))
    )

let format_range ranges =
  let result = List.map (fun x ->
      if fst x = snd x then (sprintf "%d" (fst x)) else (sprintf "%d-%d" (fst x) (snd x))) ranges in
  String.concat "," result

let read_in () =
  printf ">> ";
  Scanf.scanf "%s\n" (fun line -> line)


let main() =
  read_in()
  |> parse_range
  |> normalize_range
  |> format_range
  |> printf "%s\n"
;;

if !Sys.interactive then () else main ();;