From: Logan Capaldo <logancapaldo@...>
Date: 2006-09-05T21:43:59+09:00
Subject: Re: Does an instance know his own name?


On Sep 5, 2006, at 8:30 AM, Timothy Goddard wrote:

> You can identify an object by its object_id. Variables are just
> references to an object with a convenient name for your use. If you
> want to give an object an actual name, you have to pass it in as a
> parameter on construction.
>
> Geoff Barnes wrote:
>> If a class has built checks and raises an exception if it finds
>> something wrong, how can I tell which instance had the error?  I know
>> there's an object_id, but can I know the name of the objects own
>> instance variable?
>>
>> huey = Nephew.new
>> duey = Nephew.new
>> luey = Nephew.new

It is sort of possible to find out someone's name. The following of  
course, is easily breakable.
% cat names.rb
class Nephew
   def name(&block)
     names_objects = eval("local_variables.inject({}){ |h, k| h[k] =  
eval(k); h}", block)

     names_objects.find { |k, v| v.object_id == object_id }.first
   end
end

huey = Nephew.new
duey = Nephew.new
louie = Nephew.new

puts huey.name{}


% ruby names.rb
huey