parse-filename.sml

structure ParseFilename = struct

open Util
       
infixr 0 $
         
fun parse_filename (on_file, on_error) (pos_or_neg, filename) =
  let
    val neg_mark = "!"
    val len_neg_mark = String.size neg_mark
    fun determine_pos_or_neg s =
      if String.isPrefix neg_mark s then
        (false, trim $ String.extract (s, len_neg_mark, NONE))
      else
        (pos_or_neg, s)
    val (dir, base, ext) = split_dir_file_ext filename
  in
    if ext = SOME "pkg" then
      let
        (* val split_lines = String.tokens (fn c => c = #"\n") *)
        (* val read_lines = split_lines o read_file *)
        val filenames = read_lines filename
        val filenames = map trim filenames
        (* val () = app println filenames *)
        val filenames = List.filter (fn s => not (String.isPrefix "(*" s andalso String.isSuffix "*)" s)) filenames
        (* val () = app println filenames *)
        val filenames = List.filter (fn s => s <> "") filenames
        val filenames = map determine_pos_or_neg filenames
        (* val filenames = map (curry join_dir_file dir) filenames *)
        val filenames = map (mapSnd $ curry OS.Path.concat dir) filenames
      in
        parse_filenames (on_file, on_error) filenames
      end
    else if ext = SOME "timl" orelse ext = SOME "etiml" then
      on_file (pos_or_neg, filename)
    else on_error $ sprintf "Unknown filename extension $ of $" [default "<EMPTY>" ext, filename]
  end
    
and parse_filenames params filenames =
    app (parse_filename params) filenames

fun expand_pkg on_error filename =
  let
    val r = ref []
    fun on_file a = push_ref r a
    val () = parse_filename (on_file, on_error) filename
  in
    rev $ !r
  end
    
end