From: Gary Wright <gwtmp01@...>
Date: 2009-04-09T06:13:39+09:00
Subject: Re: Instantiate different class based on variable contents


On Apr 8, 2009, at 4:40 PM, stephen O'D wrote:
> dispatch = {
>  'Foo' => Foo,
>  'Bar' => Bar
> }
>
> obj = dispatch[var].new(...)


This can sometimes be the best approach because if you simply  
translate arbitrary text to a class name you are allowing arbitrary  
classes to be instantiated.  It just depends on where your text is  
coming from.

Rick DeNatale recently posted in [ruby-talk:332670] this nice solution  
to mapping text to class objects:

> def constantize(camel_cased_word)
>   camel_cased_word.
>     sub(/^::/,'').
>     split("::").
>     inject(Object) { |scope, name| scope.const_defined?(name) ?
> scope.const_get(name) : scope.const_missing(name) }
> end