From: MenTaLguY <mental@...>
Date: 2007-12-14T07:51:55+09:00
Subject: Re: Newbie Question: What is a class for?

Very loosely speaking, classes are a way of grouping together
functions that work with a particular sort of data structure or
object.  Functions that have been grouped in a class are often
called "methods".  Since every object has an associated class,
if you have an object, you have explicit access to the functions
for working with it.

One of the advantages of this is that you can have different
functions with the same name, differentiated by the sort
of object they work on (this is called "polymorphism").

For example, since we have a Float class and an Integer class,
we can define two functions called to_s; one in Float
(Float#to_s) that knows how to convert a floating-point number
to a string, and one in Integer (Integer#to_s) that knows how
to convert an integer to a string.

Then you can simply write foo.to_s to get the value of the
variable "foo" as a string, regardless of whether it is an
Integer or a Float.  The class of the object on the left
side of the period determines which implementation of #to_s
to call.  (The object on the left side of the period -- the
"receiver" -- shows up inside the called method as "self",
btw.)

Does that help a bit?

-mental