From: ara.t.howard@...
Date: 2006-10-12T01:10:57+09:00
Subject: Re: PHP-like Array/Hash creation in Ruby

On Thu, 12 Oct 2006, Jan Reitz wrote:

> my problem is that if i have an multi dimensional array, and it needs to
> grow (by itself if i assign values outside of the allocated space), the
> newly created will be "nil" so i cant use my own class for that.
>
> in c# 2.0 i would write
> List<List<string>> mda = new List<List<string>>()
> mda[99][99] = "test";
>
> Tada, tested it and it does _not_ work, lol.....
>
> BUT what hinders ruby to be better than that....
>
> the question i ask is is it doable ?  can someone help solving ?  im stuck
> with this "cant reassign self" or whatever it said.

harp:~ > cat a.rb
class MArray < Array
   class DimProxy
     def initialize(d, i) @d, @i = d, i end
     def inspect () @d.inspect << " [[ #{ @i } ]]" end
     def dp(i) DimProxy.new self, i end
     def [](i) dp i end
     def []= i, v
       (a = [])[i] = v
       @d[@i] = a
       v
     end
   end

   def [](i) super or dp i end
   def dp(i) DimProxy.new self, i end
end

ma = MArray.new

ma[0][1][2] = 42

puts "ma[0][1][2] : #{ ma[0][1][2].inspect }"
puts "ma[0][1]    : #{ ma[0][1].inspect }"
puts "ma[0]       : #{ ma[0].inspect }"
puts "ma          : #{ ma.inspect }"


harp:~ > ruby a.rb
ma[0][1][2] : 42
ma[0][1]    : [nil, nil, 42]
ma[0]       : [nil, [nil, nil, 42]]
ma          : [[nil, [nil, nil, 42]]]


-a
-- 
my religion is very simple.  my religion is kindness. -- the dalai lama