From: Marnen Laibow-Koser <marnen@...>
Date: 2009-11-28T07:00:58+09:00
Subject: Re: Class variables, instance variables, singleton; Ruby v.

Ralph Shnelvar wrote:
> Newb here coming from C++
> 
> Ok, I _think_ I know what a class variable is.  It is similar to a
> static variable in a class in C++.  Rght?

Yes.

> 
> An instance variable is apart of an instantiated class, right?

Not an "instantiated class", but a class instance -- which pretty much 
describes everything in Ruby, since everything is an object.

> 
> What's a singleton?  I don't think it's the same as as singleton in
> C++ parlance.

But you are wrong.

> 
> - - -
> 
> If Class X wants to access a class variable and/or constant in Class Y, 
> must a class
> method be defined 

For variables, yes.  Constants are directly accessible.  Remember, Ruby 
has no such thing as public data members in C++.

> or is there a direct way to do it?

Only for constants (you know, the Class::CONSTANT syntax).

> 
> Besides the Pickaxe book, can anyone recommend a document that
> describes this a bit more clearly?

The Pickaxe book explains all this *very* clearly.

> 
> - - -
> 
> So I did a search for "ruby for c++ programmers." on Google and came
> up with exactly one article
> (http://californickation.blogspot.com/2008/02/first-look-at-ruby.html)
> ... one that says "Another funny fact is that searching for "Ruby for
> Java programmers" retrieves a few articles right on the first page while 
> "Ruby for C++ programmers" does not."
> 
> Anyone know of any articles?

Do you really need something like that?  And if you do, won't the Java 
articles suffice?

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
Posted via http://www.ruby-forum.com/.