From: Marnen Laibow-Koser <marnen@...>
Date: 2010-02-04T04:13:13+09:00
Subject: Re: Dynamic Class Instance?

Kale Davis wrote:
> I am creating a Ruby script that basically:
> 1) Has a prompt that gets a command string (ex. 'edit user1 15')
> 2) Parses the string
> 3) Runs specific command (like 'edit' or 'new')
> 4) Repeats
> 
> From a functional level I know how to make this work, but how do I make
> it dynamic in the sense that another user could easily add their own
> commands by adding a new subclass?
> 
> I was thinking something like this:
> 
> class Update < Command
>   ...
> end
> 
> The problem is I don’t know how to dynamically create a new 'Update'
> instance if that is the command string (ie 'update user')? I know how to
> call a method using 'send' and I guess that would be another approach
> maybe, but is there something for classes?

Classes are objects too.  They respond to Object#send.

> 
> cmd = gets.chomp  #ie 'update user'
> c = cmd.split(' ')[0].new #simple parsing example
> c.run
> 
> Thanks for any help!
> Kale

Best,
-- 
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
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