From: Xavier Noria <fxn@...>
Date: 2006-03-09T00:00:29+09:00
Subject: Re: Newbie: sorting an array of custom objects

On Mar 8, 2006, at 15:38, Einar H�st wrote:

> As a project for learning Ruby, I'm writing a simple game. I have  
> some simple objects that I would like to be able to sort  
> 'automatically' in an array. In Java, I can implement the  
> Comparable interface to make the Array.sort method do this for me.  
> I'm sure I can do something similar or simpler i Ruby, I just don't  
> know how. Can anyone help? An even more elegant solution would be  
> to able to say to the array 'just put this object where it  
> belongs', without really having to sort the whole array.

The analogous approach in Ruby uses the Comparable mixin:

   class Foo
     include Comparable

     def <=>(other)
       # custom order logic
     end
   end

which, based on the custom <=>, in addition provides for free the  
operators <, <=, ==, >=, and >.

-- fxn