From: Marcelo Alvim <malvim@...>
Date: 2006-08-16T05:49:51+09:00
Subject: [QUIZ] Newbie doubts about the quiz

Hey, People.

I'm a newbie, as the subject implies, and some questions about Ruby
raised when I was trying to solve this quiz.

I'm not trying to create a very fast solution, I'm only trying to
learn mor of the language. So I'm trying a simple depth-first search
approach.

I'm going to have this two-dimensional array representing the board.
At each place of the board, I'll probably put the number that is
currently on that place.

The problem, now, is that I chose not to assume the board as a torus,
but as a flat square. So, I'm doing that simple math going from one
square to the next: if it's an horizontal move, I add 3  or -3 to X;
if it's vertical, apply the same to Y; if it's the diagonal, add 2 or
-2 to both of them. Well, you already know that. Unfortunately, Ruby's
behavior of wrapping arrays over using their negative indices, which I
like very much on most cases, is kind of annoying now, since I want to
invalidate access to negative indices.

So, I thought of some approaches for "solving" this problem of mine,
and would like to know your opinions:

1) I could create a class that extends Array, or encapsulates one, and
define the #[] and #[]= methods. Then those methods would check the
negative indices and return nil if they were negative.

2) I could alias_method those methods for the actual Array classe and
override the original ones, also checking indices inside (Though I
think if I use this approach in anything but my simple quiz solution,
I would have to return the Array class back to normal afterwards).

3) I could check indices on my code everytime I need, outside of any
Array class.

4) You guys could teach me a super-cool Ruby-esque way to do that that
I can't even think about right now.

Thanks for your patience,
Alvim.