deps.ml

module M = Set.Make(String)

let fold_lines : ('a -> string -> 'a) -> 'a -> string -> 'a =
  fun f acc fname ->
    let ic = open_in fname in
    let acc = ref acc in
    try
      while true do
        acc := f !acc (input_line ic)
      done; assert false
    with End_of_file -> close_in ic; !acc

let is_mod_char : char -> bool = fun c ->
  match c with
  | 'a'..'z' | 'A'..'Z' | '0'..'9' | '_' | '-' | '.' -> true
  | _                                                -> false

let rec handle_line : M.t -> string -> M.t = fun s l ->
  let len = String.length l in
  if len = 0 then s else
  let pos = ref 0 in
  while !pos < len && not (is_mod_char l.[!pos]) do incr pos done;
  let start = !pos in
  while !pos < len && is_mod_char l.[!pos] do incr pos done;
  let siz = !pos - start in
  let m = String.sub l start siz in
  let m =
    let len = String.length m in
    if len > 0 && m.[len-1] = '.' then String.sub m 0 (len - 1) else m
  in
  let get_module m =
    let i = try String.index m '.' with _ -> assert false in
    String.sub m 0 i
  in
  let s =
    if m <> "" && m <> "." && String.contains m '.' then
      M.add (get_module m) s
    else s
  in
  handle_line s (String.sub l !pos (len - !pos))

let _ =
  let work f n =
    let mods = M.remove n (fold_lines handle_line M.empty f) in
    M.iter (Printf.printf "#REQUIRE %s.\n%!") mods
  in
  match Sys.argv with
  | [| _ ; f ; n |] -> work f n
  | _               ->
      Printf.eprintf "Usage: %s file.dk modname\n%!" Sys.argv.(0)