From: John Johnson <johnatl@...>
Date: 2006-04-29T05:53:55+09:00
Subject: Re: how to create Class object with name determined at runtime

You can use eval() to do that, like so:
irb(main):001:0> a='String'
=> "String"
irb(main):002:0> b=eval("#{a}.new")
=> ""
irb(main):003:0> b.class
=> String
irb(main):004:0>

In the second irb line, the contents of the variable _a_ are substituted in the string before the .new. It amounts to b=eval("String.new").

Regards,
  JJ
 
On Friday, April 28, 2006, at 02:55PM, Bill Roberts <bill.roberts@planet.nl> wrote:

>I hope someone can help with this - I am a Ruby newbie.
>
>In my code I want to decide at runtime which type of object to create, 
>based on a variable holding the name of the class.
>
>So I have classes Foo and Bar and a string todays_class.
>
>If todays_class = "Foo"  I want to say my_obj = Foo.new
>if todayS_class = "Bar" then my_obj = Bar.new
>
>Except I've got a lot more than two classes and I'd prefer not to use an 
>if or case statement, so that I don't need to change the code if I add 
>another one to the list.
>
>Any suggestions on a neat way to do this?
>
>Thanks
>
>-- 
>Posted via http://www.ruby-forum.com/.
>
>
>


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