From: Brian Candler <B.Candler@...>
Date: 2003-05-15T17:59:22+09:00
Subject: Re: Marshal string format

On Thu, May 15, 2003 at 09:32:54AM +0900, Pablo Lorenzzoni wrote:
> Given a class (let's take the Pickaxe example)
> 
> class Klass
>   def initialize(str)
>     @str=str
>   end
>   def sayHello
>     @str
>   end
> end
> 
> o=Klass.new("hello\n")
> data=Marshal.dump(o)
> 
> p data => "\004\006o:\nKlass\006:\t@str\"\nhello"
> 
> What does all the meta-data in string "data" mean?

Have a look through marshal.c, it's very clearly written.

Marshal is intended to be an 'opaque' string that you can squirt into a file
or down a wire, and recreate a copy of the same object at the other end. If
you want it to be parseable, you might prefer to use a different marshaling
library (e.g. YAML or SOAP). Or you can extract the data about your object
directly:

   p o.class
   p o.instance_variables
   o.instance_variables.each { |v| p o.instance_variable_get(v) } # 1.8 only

Marshal is very, very fast though. I would love to see a C library for Perl
which reads/writes in Ruby's Marshal format :-)

Cheers,

Brian.