From: Logan Capaldo <logancapaldo@...>
Date: 2006-01-17T08:09:30+09:00
Subject: Re: const_defined? behavior


On Jan 16, 2006, at 5:52 PM, Daniel Amelang wrote:

> Hi Nobu,
>
>> defined?(IO::SYNC)
>
> In my case, the constant's name is stored in a variable. So, I'd have
> to resort to doing an 'eval' if I were to follow your suggestion. So
> at least I have two options now:
>
> # Option 1 (Nobu's suggestion)
> found = eval("defined?(obj::#{const})")
>
> # Option 2 (My original idea)
> found = obj.respond_to?(:constants) && obj.constants.member?(const)
>
> Any better ideas? I usually try to stay clear of 'eval' if I can.
>
> Dan Amelang
>

def const_defed(var)
       var.split(/::/).inject(Object) do |left, right|
                begin
                   left.const_get(right)
                rescue NameError
                     break nil
                end
       end
end