anchor.diff:  default_value(Desc) ->
     case re:run(Desc,"\\[default: (.*)\\]", [{capture, [1], list}, caseless]) of
       {match, [DefaultValue]} -> DefaultValue;
  -    nomatch                 -> false
  +    nomatch                 -> undefined
     end.
   
   parse_args(Args, Options) ->
  
positive.code: 
  opt(Short)            -> #option{short=Short}.
  opt(Short, Long)      -> #option{short=Short, long=Long}.
  opt(Short, Long, Ac)  -> #option{short=Short, long=Long, argcount=Ac}.
  
  partition_test_() ->
    [ ?_assertEqual({"foobar", ""}     , partition("foobar"      , "abc"))
  
negative.code:   ].
  
  option_parse_test_() ->
    [ ?_assertEqual(opt("-h"), option_parse("-h"))
    , ?_assertEqual(opt(undefined, "--help"), option_parse("--help"))
    , ?_assertEqual(opt("-h", "--help"), option_parse("-h --help"))
    , ?_assertEqual(opt("-h", "--help"), option_parse("--help -h"))
    , ?_assertEqual(opt("-h", "--help"), option_parse("-h,--help"))
  
    , ?_assertEqual(#option{short="-h", argcount=1, value=undefined},
                    option_parse("-h TOPIC"))
    , ?_assertEqual(#option{long="--help", argcount=1, value=undefined},
                    option_parse("--help TOPIC"))
    , ?_assertEqual(#option{short="-h", long="--help", argcount=1, value=undefined},
                    option_parse("-h TOPIC --help TOPIC"))
    , ?_assertEqual(#option{short="-h", long="--help", argcount=1, value=undefined},
                    option_parse("-h TOPIC, --help TOPIC"))
    , ?_assertEqual(#option{short="-h", long="--help", argcount=1, value=undefined},
                    option_parse("-h TOPIC, --help=TOPIC"))
  
    , ?_assertEqual(#option{short="-h"}, option_parse("-h  Description..."))
    , ?_assertEqual(#option{short="-h", long="--help"},
                    option_parse("-h --help  Description..."))
    , ?_assertEqual(#option{short="-h", argcount=1, value=undefined},
                    option_parse("-h TOPIC  Description..."))
    , ?_assertEqual(#option{short="-h"}, option_parse("    -h"))
    , ?_assertEqual(#option{short="-h", argcount=1, value="2"},
                    option_parse("-h TOPIC  Descripton... [default: 2]"))
  