From: Dustin Barker <dustin.barker@...>
Date: 2008-07-21T07:29:03+09:00
Subject: Re: [QUIZ] Records and Arrays (#170)

Here's my solution - playing w/ anonymous classes for the adapter  
solutions, probably not ideal since it doesn't provide all the methods  
a proper Array or arbitrary record would provide, but was fun to try  
out ;-)

require 'ostruct'

def extract_attributes(rec)
   if rec.kind_of?(OpenStruct)
     attributes = rec.marshal_dump.keys
   else
     attributes = rec.public_methods
     attributes.delete_if do |a|
       !(a =~ /^[a-z_]*$/i && attributes.include?("#{a}="))
     end
   end

   attributes
end

def aor_to_roa(arr)
   attributes = extract_attributes(arr.first)
   roa = arr.first.class.new
   attributes.each { |a| roa.send("#{a}=", []) }

   arr.each do |rec|
     attributes.each do |a|
       roa.send(a).push(rec.send(a))
     end
   end

   roa
end

def roa_to_aor(roa)
   attributes = extract_attributes(roa)
   arr = []

   roa.send(attributes.first).size.times do |i|
     arr[i] = roa.class.new
     attributes.each do |a|
       arr[i].send("#{a}=", roa.send(a)[i])
     end
   end

   arr
end

class ROAAdapter
   def initialize(arr)
     @arr = arr
   end

   def method_missing(a)
     arr = @arr
     Class.new do
       define_method(:[]) { |i| arr[i].send(a) }
     end.new
   end
end

class AORAdapter < Array
   def initialize(roa)
     @roa = roa
   end

   def [](i)
     roa = @roa
     Class.new do
       define_method(:method_missing) { |a| roa.send(a)[i] }
     end.new
   end
end

-Dustin