From: Avi Bryant <avi@...4.com>
Date: 2001-02-06T08:29:47+09:00
Subject: [ruby-talk:10389] Re: Problems creating persistent objects


On Tue, 6 Feb 2001, Danny Sofer wrote:

> Here's the synopsis:
> 
> module Storage
>   def store
>     puts "should be storing #{@f}"
>     File.open(@f, "w") { |f| Marshal.dump(@data, f) }
>   end
>   def retrieve
>     File.open(@f) { |f| return Marshal.load(f) }
>   end
> end
> 
> class Obj
>   include Storage
>   def initialize(f, m='')

<snip>

> 1) i wanted to do something like: "self = retrieve", but in the end settled
> for putting my data in to a hash (@data) and storing that instead, because
> assigning anything to self is a bit naughty. is there a more elegant way to
> round this?

How about something like

module Storage
   def new(f)
	if File.exists?(f)
		File.open(f) {|f| return Marshal.load(f) }
	else
		super
	end
   end
end

class Obj
   extend Storage
   ...
end


(me, I miss the semantics of [[Cls alloc] init] in Obj-C...)