From: Eric Hodel <drbrain@...7.net>
Date: 2006-12-03T13:01:15+09:00
Subject: Re: Serializing Ruby code

On Dec 2, 2006, at 19:06 , Victor Zverok Shepelev wrote:

> A bit of philosophy.
>
> We have Marshal[1] to serializing Ruby's objects (and also YAML and  
> so on).
> AFAIK, Rails community even uses objects serialization for  
> program's state
> saving.
> But, existing marshalling/serialization can serialize only data,  
> not plain
> code; this fact is restricting for their applications. For example,
> Smalltalk-style "image" (entire program state, which can be loaded and
> continued) is impossible.
>
> But! We have a method for translating code-to-data - ParseTree[2],  
> and we
> even have method to translate back data-to-code (though a bit  
> roundabout) -
> ruby2ruby[3].
>
> Had somebody thought about gathering all this to create full  
> solution for
> entire running program "saving" and "loading"? (Or, may be,  
> somebody already
> done this and I'm missing?)

You'd need more than that to get a full image to work (like recording  
the ObjectSpace, the symbol table, globals, ...)

Also, ParseTree doesn't capture the closure so you can't copy the  
full state of the interpreter:

$ cat closure.rb
def make_proc
   x = 1
   proc do |y| y + x end
end

p = make_proc

puts p.call(2)

require 'rubygems'
require 'ruby2ruby'

ruby = p.to_ruby

puts ruby

q = eval ruby

puts q.call(2)

$ ruby closure.rb
3
proc { |y|
   (y + x)
}
(eval):2: undefined local variable or method `x' for main:Object  
(NameError)
         from closure.rb:19:in `call'
         from closure.rb:19

-- 
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!