From: Joshua Haberman <joshua@...>
Date: 2005-10-04T15:53:24+09:00
Subject: Re: creating objects

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On Oct 3, 2005, at 11:45 PM, Hal Fulton wrote:

> Felix McCoey wrote:
>
>> i know that in PHP it is possible to do the following:
>> $class_name = 'User';
>> $$class_name->new()
>> but I want to do this in ruby like this perhaps:
>> @class_name = 'User'
>> @class_name.new
>> What is this called and is it possible in ruby. Or is there an
>> alternative to creating objects from just the class name?
>>
>
> You can always use const_get:
>
>   class_name = 'User'
>   klass = Object.const_get(class_name)
>   obj = klass.new

Also, if you can create a string of code that does what you want, you  
can always eval() it:

obj = eval("#{class_name}.new")

But the const_get solution is better.  It works because classes are  
live objects that are stored in global constants.

Josh

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