anchor.diff:    stop_ruby(Ruby),
     erruby_vm:eval_ast(Ast).
   
  -opt_spec_list() ->
  -  [
  -   {debug, $d, "debug", {integer, 0}, "Verbose level for debugging"}
  -  ].
   
   getopt(Args) ->
     getopt:parse(opt_spec_list(), Args).
  +
  +show_help() ->
  +  getopt:usage(opt_spec_list(), "erruby", "[programfile] [arguments]"),
  +  halt(1).
   
   
   install_encoder(Ruby) ->
  
positive.code: -module(erruby).
  -export([eruby/1, start_ruby/0, stop_ruby/1, parse_ast/2, main/1]).
  
  main(Args) ->
    add_lib_path(),
    {ok, Opts} = getopt(Args),
    {
     [{debug,DebugLevel}],
     [SrcFileName | RubyArgs]
    } = Opts,
    erruby_debug:start_link(DebugLevel),
    erruby_debug:debug_tmp("~p ~n", [Opts]),
    try
      erruby_debug:debug_1("input file name ~s\n", [SrcFileName]),
      erruby_debug:debug_1("input args ~s\n", [RubyArgs]),
  
negative.code:     _:E ->
        io:format("error ~p ~n", [E]),
        erlang:display(erlang:get_stacktrace())
    end.
  
  eruby(SrcFileName) ->
    {ok, Binary} = file:read_file(SrcFileName),
  