From: Tom Allison <tallison@...>
Date: 2006-01-16T22:20:06+09:00
Subject: basic question about Fixnum & Integer

Hello,
I'm really new to Ruby and rather new to OOP in general.  I've been 
using Perl for about 7 years now and have a fairly good understanding of 
that language.  I've never really entertained Python to any serious 
degree beyond 'Hello World'.  Now you know my background.

I tried to do the following:

13.lcd 3

and it failed in the irb.

Why?

My thinking is that 13 is a Fixnum class and Fixnum inherits Integer.
Integer has a method 'lcd' that returns the least common denominator.
Since Fixnum < Integer then all the methods of Integer should be 
available to all the child objects (Fixnum and super).  And if this is 
true, then calling a method like I did (Fixnum#lcd) implies an 
inheritance search to find that class.

But my thinking seems to not reflect Ruby very well.

Can someone please tell me what I did wrong in the code and also in 
thought?  It's little niggly bits like this that get frustrating.