From: Claus Spitzer <docboobenstein@...>
Date: 2005-04-12T08:03:05+09:00
Subject: Re: Factory design

Thanks to everyone who replied - My friend really appreciates the help. 
Cheers!

On Apr 11, 2005 6:50 PM, Nicholas Seckar <nseckar@gmail.com> wrote:
> A more complex, but still simple example:
> 
> class Microwave # defrosts food
>   attr_accessor :creators
>   def initialize()
>     @creators = []
>   end
>   def mode(key = nil, cls = nil)
>     delegate = cls ? (Proc.new {|path| cls.new(path)}) : Proc.new
>     creators << [key, delegate]
>   end
> 
>   def defrost(path)
>     r = nil
>     creators.each do |(key, delegate)|
>       next unless (case key
>         when nil then true
>         when Regexp then key =~ path
>         when String then key == path
>         else false
>       end)
>       return r if (r = delegate.call(path))
>     end
>   end
> end
> 
> # A delectable bit wrap. Whole wheat pita!
> class FileWrap
>   attr_accessor :contents
>   def initialize(path)
>     @path = path
>     @contents = IO.read(path)
>   end
>   def method_missing(sel, *args)
>     r = @contents.send(sel, *args)
>     if sel.to_s[-1..-1] == '!'
>       (File.open(@path, 'w') {|f| f.write(@contents)})
>     end
>     r
>   end
> end
> 
> M = Microwave.new
> 
> M.mode(/\.txt$/, FileWrap)
> M.mode(/\.ruby_object$/) {|path| Marshal.load(IO.read(path))}
> 
> # Put some stuff in the fridge
> File.open('/tmp/a_hash.ruby_object', 'w') do |f|
>   f.write(Marshal.dump(:a => 2, 'a' => 'two'))
> end
> File.open('/tmp/a_file.txt', 'w') do |f|
>   f.write('Hello World')
> end
> 
> h = M.defrost('/tmp/a_hash.ruby_object')
> puts h['a'] #=> two
> puts h[:a] #=> 2
> 
> f = M.defrost('/tmp/a_file.txt')
> puts f.contents #=> Hello World
> f.gsub!('World', 'Food')
> puts `cat /tmp/a_file.txt` #=> Hello Food
> 
> Well, it was simple. Then I became carried away.
> 
> --
> 
> Nicholas Seckar aka. Ulysses
> 
>