From: Igal Koshevoy <igal@...>
Date: 2008-06-27T03:41:42+09:00
Subject: Re: question about defined? and y

Aditya Mahajan wrote:
> On Thu, 26 Jun 2008, Ruby Freak wrote:
>> The uninitialized variable y returns from defined? as "method" rather
>> than "nil" ????
>>
>> puts defined?(x) # => nil
>>
>> puts defined?(y) # => method
>
> Are you testing this on irb or by writing on a file and running 
> through ruby? When I test this on irb, both x and y are defined as 
> methods. While running through ruby, both are nil.
If you're using an IRB with certain settings, such as the Rails console, 
it includes the "y" method as a wrapper providing functionality similar to:

    def y(*args)
        require 'yaml'
        print YAML::dump(args)
    end

This command is useful for inspecting data structures.

-igal