From: John Joyce <dangerwillrobinsondanger@...>
Date: 2007-05-06T13:04:02+09:00
Subject: Re: How can I output an object/variable's name?


On May 6, 2007, at 9:41 AM, Gary Wright wrote:

>
> On May 5, 2007, at 6:02 PM, Rick DeNatale wrote:
>> On 5/5/07, John Joyce <dangerwillrobinsondanger@gmail.com> wrote:
>>> What I'd like to do is similar to the idea of processing files and
>>> outputing results with names of files.
>>> I want to do the same with objects.
>>> I wrote an little code block just to talk back to me and tell me if
>>> an object is tainted or not. ("I'm making it plain English  
>>> sentences,
>>> rather than simply true or false)
>> [..]
>> Variables are just names for objects, and aren't properties of the
>> objects themselves.  Objects don't know what folks are calling them.
>
> You can't go from an arbitrary object reference to an identifier, but
> you can go from an identifier to an object reference via eval:
>
> a = 42
> @foo = 'bar'
> ["a", "@foo", "Array"].each { |id|
>   puts "#{id} references a #{eval(id).class}"
> }
>
> # output
>
> a references a Fixnum
> @foo references a String
> Array references a Class
>
>
>
> Gary Wright
Gary I think this does what I'm looking for. It's a little hackish to  
me, but it seems to work.
I find eval to be one of those less obvious tools. I was just reading  
up on eval and its cadre of similar methods last night. A very  
mystical bunch to me still.