Define option name. Argument string is processed by
      shellwords routine defined in Text::ParseWords module. Be sure that
      this module sometimes requires escape backslashes.
    Any kind of string can be used for option name but it is not
        combined with other options.
    
        option --fromcode --outside='(?s)\/\*.*?\*\/'
    option --fromcomment --inside='(?s)\/\*.*?\*\/'
    
    If the option named default is defined, it will be used
        as a default option.
    For the purpose to include following arguments within replaced
        strings, two special notations can be used in option definition.
    String "$<n>" is
        replaced by the nth argument after the substituted option, where
        n is number start from one. Because
        "$<0>" is replaced by the
        defined option itself, you have to care about infinite loop.
    String "$<shift>" is
        replaced by following command line argument and the argument is removed
        from list.
    For example, when
    
        option --line --le &line=$<shift>
    
    is defined, command
    
        greple --line 10,20-30,40
    
    will be evaluated as this:
    
        greple --le &line=10,20-30,40
    
    There are three special arguments to manipulate option
        behavior and the rest of arguments. Argument
        "$<move>" moves all following
        arguments there, "$<remove>"
        just removes them, and "$<copy>"
        copies them. These does not work when included in a part of string.
    They take optional one or two parameters, those are passed to
        Perl "splice" function as
        offset and length.
        "$<move(0,1)>" is same as
        "$<shift>";
        "$<copy(0,1)>" is same as
        "$<1>";
        "$<move>" is same as
        "$<move(0)>";
        "$<move(-1)>" moves the last
        argument; "$move(1,1)" moves second
        argument. Next example exchange following two arguments.
    
        option --exch $<move(1,1)>
    
    Because "$<move(0,0)>"
        does nothing, you can use it to ignore option.
    
        option --deprecated $<move(0,0)>