From: Prime@...
Date: 2007-04-18T11:45:06+09:00
Subject: Re: nil in evaluations

I am not sure this is what you wanted but,

if g(x).nil? || f(x).nil?
	p "nil found"
else
	p "no nil"
end

can be used to evaluate if the function equals nil



On 2007-04-17 19:08:05 -0700, progcat@comcast.net said:

> 
> 
> Problem:  I have functions that sometimes evaluate to nil and cause my
> program to crash in comparisons, etc.
> 
> For example g(x) and f(x) either could be nill in the following:
> if g(x) > f(x)
>      p "not reached"
> else
>      p "also not reached but I want it to reach here if either fuction
> returns nil"
> end
> 
> What can I do to make any comparison that has nil in it to evaluate to
> false?  I have seen operator overloading and class definitions in
> ruby, so I imagine this would be quite simple.
> 
> (I know I can set g(x) and f(x) to variables before the if statement,
> but I really want to avoid that)
> 
> Thanks in advance,
> Tom