From: "Christoffer Lernö" <lerno@...>
Date: 2007-03-12T04:34:50+09:00
Subject: Re: directly modify a part on an array for quiz #117 purposes

On Mar 11, 2007, at 20:24 , Albert Ng wrote:

> From Ruby quiz #117 (much fun)
>
> #bad code by me, interesting bits shamelessly stolen from Dave Burt
> neighborhood=[@grid[x0][y0], @grid[x0][y1], @grid[x1][y0], @grid[x1] 
> [y1]]
>
> where each element of @grid[][] is a string, x1 = x0+1, and y1=y0+1
>
> is there a way to do the following:
> @grid[x0][y0], @grid[x0][y1], @grid[x1][y0], @grid[x1][y1] = @grid 
> [x1][y0],
> @grid[x0][y0], @grid[x1][y1], @grid[x0][y1]
>
> in a more readable way
>
> I thought
>
> *neighborhood = @grid[x1][y0], @grid[x0][y0], @grid[x1][y1], @grid 
> [x0][y1]
>
> would be equivalent, but it isn't.

Did you have a look at my code?

I used this:

2.times do |y|
   2.times do |x|
     class_eval "def xy#{x}#{y}; @grid[@x + #{x}, @y + #{y}]; end"
     class_eval "def xy#{x}#{y}=(v); @grid[@x + #{x}, @y + #{y}] = v;  
end"
   end
end

To allow me to write the rotations as

     def ccw90
       self.xy00, self.xy10, self.xy01, self.xy11 = xy10, xy11, xy00,  
xy01
     end

     def cw90
       self.xy00, self.xy10, self.xy01, self.xy11 = xy01, xy00, xy11,  
xy10
     end


Might be an idea?


/Christoffer