From: Sharon Phillips <phillipsds@...>
Date: 2007-07-08T12:21:59+09:00
Subject: Re: Polymorphic Code


On 08/07/2007, at 12:28 PM, Ari Brown wrote:

> Hey,
> 	Just a curious question.
>
> So does ruby have anything to accommodate for it? If not, what  
> about a work around?
>
> Thanks,
> ~ Ari
> English is like a pseudo-random number generator - there are a  
> bajillion rules to it, but nobody cares.
>
>

Do you mean something like this (example below)?
What you should be aware of is that Ruby doesn't require you to cast  
objects to a particular type in order to call a method. You may have  
a number of objects of completely different classes in your  
collection, and as long as they all respond to the method you're  
interested in then you can iterate through and call that method (duck  
typing). This makes interfaces redundant and is a fantastically  
useful feature.

Cheers,
Dave

class Animal
   attr_reader :name

   def initialize(name)
     @name= name
   end

   def noise
     "some strange grunty sound"
   end

end

class Dog < Animal
   def noise
     "Woof!"
   end
end

class Cat < Animal
   def noise
     "Meow"
   end
end

animals= [Dog.new("Fido"), Cat.new("Socks"), Animal.new("Suzi")]
animals.each do |animal|
   puts "#{animal.name} says #{animal.noise}"
end

 >

Fido says Woof!
Socks says Meow
Suzi says some strange grunty sound