From: Massimiliano Mirra <list@...>
Date: 2002-03-20T23:51:24+09:00
Subject: Re: [ANN] Xml Serialization for Ruby

On Tue, Mar 19, 2002 at 10:53:44PM +0900, Morris, Chris wrote:
> Again, another good point. Even with my typeless approach, array and hash
> will have to have type elements ... well, no they wouldn't -- but we need
> some way of delineating each element or key/value pair. Right now it's:
> 
>   <Array>
>     <Element>thing</Element>
>   <Array>
> 
>   <Hash>
>     <Pair>
>       <Key>thing</Key>
>       <Value>other thing</Value>
>     </Pair>
>   </Hash>
> 
> I'd like to be able to squeeze those down somehow. 

Hmmm... how do you know what class are the contained elements going to
be?  Do you parse the element content?

> > I agree, that feels more OOP to me too.  My application had some
> > requirements that prevented that:
> > 
> > - I did not know in advance what classes had to be marshallable;
> > - even if I did, I could not create a marshaller object for each of
> >   them because there were going to be a lot and performance would have
> >   decreased;
> > - I could not use a global object either, as the stuff needed to be
> >   thread safe, and I could not use a mutex for the same 
> > performance reasons.
> 
> Hmmm ... that's interesting. I can see with your first issue where my
> approach just wouldn't work -- well, could you include the module into
> Object?
> 
>   class Object
>     include XmlSerialization
>   end
>
> The mods to the standard types would still work, and then everything (?)
> gets to_xml from_xml?
>
> As for the other two options, does the included module in Object handle
> performance and threading issues? Because you wouldn't have all these
> additional marshaling objects -- they're built into each object you already
> have.

Marshalling requires an instance of an XML parser.  To be thread safe,
either as many instances are serializable objects would be needed
(resource unfriendly), or a global instance with mutex access
(performance unfriendly), or a limited number of instances scheduled
by some mechanism (programmer unfriendly ;-) ).

Well, but I'm taking for granted that you are marshalling XML back
into objects via an XML parser, too, and I might be wrong as I've not
looked into the internals of your code...

Massimiliano