From: Robert Klemme <shortcutter@...>
Date: 2009-09-16T17:19:27+09:00
Subject: Re: Making an array wrap, where last index + 1 = first index

2009/9/15 Aldric Giacomoni <aldric@trevoke.net>:
> def class Array2D < Array
>  def []( index )
>    super [] index % self.length
>  end
> end
>
> How about that?

10:16:29 c$ ruby -c <<EOF
> def class Array2D < Array
>  def []( index )
>    super [] index % self.length
>  end
> end
> EOF
-:1: formal argument cannot be a constant
def class Array2D < Array
                 ^
-:1: syntax error, unexpected '<', expecting '\n' or ';'
def class Array2D < Array
                   ^
-:3: syntax error, unexpected tIDENTIFIER, expecting kEND
   super [] index % self.length
                 ^
-:5: syntax error, unexpected kEND, expecting $end
10:16:35 c$

Rather

10:18:27 c$ ruby19 <<EOF
> class ArrayWrap < Array
>  def []( index )
>    super(index % length)
>  end
> end
> a = ArrayWrap.new(5) {|i| i}
> 7.times do |i|
>   printf "%2d %2d\n", i, a[i]
> end
> EOF
 0  0
 1  1
 2  2
 3  3
 4  4
 5  0
 6  1
10:19:08 c$

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/