From: Eric Hodel <drbrain@...7.net>
Date: 2009-08-20T01:41:13+09:00
Subject: Re: #has_arguments?

On Aug 19, 2009, at 8:08, Trans <transfire@gmail.com> wrote:
>> Normally I just make the default value for an optional parameter nil,
>> and check for nil.
>>
>> If nil is a valid value, then I'd do something like
>
> Right, it precisely the times when nil is a valid value that it is a  
> problem.

class X
   NONE = Object.new

   def blah(a = NONE)
     # ...
   end
end

Suffices for nil as valid value