From: Ben Bleything <ben@...>
Date: 2007-02-23T06:41:25+09:00
Subject: Re: Best way to get a class object from its name?

On Fri, Feb 23, 2007, Wes Gamble wrote:
> eval("#{requested_controller_class}.respond_to?('session_data_not_needed_by?')")
> 
> where requested_controller_class is the name of an existing (controller)
> class.
> 
> Is the above code the best of way of invoking respond_to? on the class
> in question, or is there some better way to get the actual class object
> based solely on it's name?

>> str = "ActiveRecord::Base"
=> "ActiveRecord::Base"
>> str.constantize.respond_to? :new
=> true

String#constantize is provided by Rails someplace.  In non-Rails Ruby
code, you could do this:

>> Module.const_get( 'ActiveRecord' ).const_get( 'Base' ).respond_to?
>> :find
=> true

Of course, if it's a single-level, you only need one of those.

Cheers,
Ben