From: David Alan Black <dblack@...>
Date: 2001-11-17T03:04:02+09:00
Subject: [ruby-talk:25557] Re: Getting a class object from a string containg its name

Hello --

On Sat, 17 Nov 2001, Lars Christensen wrote:

> I need to get a reference to a class object from a string with the name of
> the class. I want to do this in a secure way because the string comes from
> an external source. I could not find any easy way to convert a string or
> symbol to a class reference. I found two approaches though:

You can use const_get.  Here's a somewhat overwritten example :-)

   class ClassFinder
     def find_class(string)
       type.const_get(string)
     end
   end

   c = ClassFinder.new
   C = c.find_class("String")
   class C
     def thing
       puts "Hi!"
     end
   end

   "some string".thing    # "Hi!"

There are probably subtleties about scope and visibility and such that
I'm not addressing....


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav