From: Matthew Moss <matthew.moss.coder@...>
Date: 2006-08-16T10:23:41+09:00
Subject: Re: [QUIZ] Newbie doubts about the quiz

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

I haven't submitted a solution... I started working on one, but just
haven't had time to complete it. But I did start with something like
this:

class Coord
   attr_reader :x, :y

   def initialize(x, y)
      @x, @y = x, y
   end

   def valid(n)   # returns true if coord fits on an n-square board
      (0...n).include?(@x) and (0...n).include?(@y)
   end

   def to_s
      "(#{@x}, #{@y})"
   end

   def adjacents
      [  Coord.new(@x, @y - 3),
         Coord.new(@x, @y + 3),
         Coord.new(@x - 3, @y),
         Coord.new(@x + 3, @y),
         Coord.new(@x - 2, @y - 2),
         Coord.new(@x - 2, @y + 2),
         Coord.new(@x + 2, @y - 2),
         Coord.new(@x + 2, @y + 2)
      ]
   end
end

Then, let's say you randomly start at (1, 3). You can get started like:

c = Coord.new(1, 3)
c.adjacents.each { |d| puts d if d.valid(5) }

Not terribly efficient, but you know what they say...  Vi is at the
heart of evil...  I mean, premature optimization is terribly
effective...  Wait a sec...  That's not right.