From: Jamal Soueidan <jkhaledsoueidan@...>
Date: 2007-04-05T06:56:46+09:00
Subject: Re: nil? and non-existent objects

François Montel wrote:
> Why is it that the nil? method can sometimes be called on an object that
> doesn't exist, and other times will return an error. Under what
> circumstances can you call the nil? method on a non-existent object?
> 
> Consider:
> 
>>> puts x = 1 if x.nil?
> => 1
>>> puts ‘z is not defined’ if z.nil?
> => NameError: undefined local variable or method ‘z’
> 
> Someone mentioned that = has higher precedence than if, so it could be
> that in the first statement x is assigned 1 before the conditional
> statement is run. However, x.nil? would then always return false.

You could also fix it this way :)

----------------------------------------------

def x
  @x
end

def x=(val)
   @x = val
end

puts x=1 if x.nil?

----------------------------------------------

This would output: 1


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