From: Andreas Warberg <andreas.warberg@...>
Date: 2006-12-06T00:47:55+09:00
Subject: Unexpected scope range

I am new to Ruby but have a strong java background.

So far I have been enjoying Ruby a great deal.

But I have been wondering about why the scope of variables works as it
does. It seems that very often, I need to prefix my variables with
either @ or $ in order to access them in method calls.
I did some searching for an explanation but did not find any.

In java variables can be defined and used like this:

Object x = myX;

public void printx(){
    System.out.println(x);
}

x is available when the method is called. This is not the case with
Ruby:

x = myX

def printx
   puts x
end

Running the code will produce an error: "NameError: undefined local
variable or method `x' for main:Object".

In order to reveal x to the method one must, for instance, declare it
global by prefixing the $. This requires more typing (which, in many
other respects, ruby tries to avoid).

How come the scope works in this way? I expected the visibility of
variables to flow down into the code tree (but not up, of course).

Thank you.

Regards, Andreas

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