Message: 2
Date: Fri, 31 Aug 2012 13:40:58 -0500
From: Tarl Neustaedter <tarl-b2@tarl.net>
To: The OpenBIOS Mailinglist <openbios@openbios.org>
Subject: Re: [OpenBIOS] Fwd: [PATCH] Adds local variable support to
OpenBIOS.
Message-ID: <5041053A.90303@tarl.net>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

On 2012-Aug-31 09:50 , Programmingkid wrote:

Are you saying my-variable is better than myVariable?

Yes.

How do global variables get you in trouble in recursion? Do you have 

an example?

Not off-hand, we learn to avoid doing that. To construct one - let's 
take a method doing recursion properly, and break it:

\ Correct way, using stack manipulation
: fibonacci ( fib -- return ) recursive
   dup 2 >= if                 ( fib )
      dup 1- fibonnaci         ( fib fib-1 )
      swap 2 - fibonnaci       ( fib-1 fib-2 )
      +                        ( fib )
   then                        ( fib )
;

\ Incorrect way - using variable "fib", which will get overwritten 
during recursion
0 value fib;
: fibonnaci ( fib -- return ) recursive
   to fib \ to avoid stack manipulation
   fib 2 < if
      fib exit
   then
   fib 1- fibonnaci           ( fib-1)
   fib 2 - fibonnaci          ( fib-1 fib-2 )
   +                          ( fib )
;