(* Unix shells. *)

module Shell;

let breakLines =
  proc(answer)
    if answer is "" then []
    else
      text_explode("\n",
        text_sub(answer, 0, text_length(answer)-1))
    end
  end;

(* E.g.: exec("/bin/ls -l"); *)
let exec =
  proc(command)
    breakLines(
      process_filter(processor, text_explode(" ", command), ""))
  end;
  
(* E.g.: sh("ls *.ps"); sh("ls | /usr/ucb/wc"); *)
let sh =
  proc(command)
    breakLines(
      process_filter(processor, ["/bin/sh"], command))
  end;
  
(* Interactive shell. Exit with "quit". *)
let shi =
  proc()
    loop
      let l = rd_getLine(rd_stdin);
      if text_equal(l, "quit") then exit end;
      wr_putText(wr_stdout,
        process_filter(processor, ["/bin/sh"], l));
      wr_flush(wr_stdout);
    end
  end;