From: Mike Stephens <rubfor@...>
Date: 2009-04-23T07:57:45+09:00
Subject: Back to Fundamentals

Phlip wrote:

> 
> That's "overloading", not "polymorphism".
> 

Before this thread I thought I understood polymorphism. Suddenly 
confused, I went off to Wikipedia and there are all sorts of arcane 
stuff there. I'm impressed how many technical terms people can use.

Here's what I think it means: You can declare procedures (and, by 
extension, operators) that have identical names (eg 'hire', 'sort', '+') 
but behave differently depending on the nature of the object concerned. 
This saves you generating unique names for each type of data. So 
polymorphic means 'behaving differently in different situations'.

If this is the case (forget all the different ways you might achieve 
that), then Ruby must deliver mainstream polymorphism because it uses 
classes. A class encapsulates procedures and therefore allows names to 
be re-used. The appropriate behaviour is selected by the type of the 
object concerned.

Again if this simplistic view is correct, your examples are not to do 
with Ruby and polymorphism, they are to do with making classes contain 
more than one type of object (and why would you feel entitled to do 
that?)
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