Re: [Qemu-devel] Machine description, an alternativ using XML

[Jamie Lokier <jamie@shareable.org>]

Andreas Färber wrote:
> >XML already has a way of describing objects (elements) attributes of
> >those objects (attributes) and objects nested within those objects
> >(nested elements).
> 
> True, but XML itself does not allow for arbitrary graphs, only trees.  
> Unless of course you start using RDF/etc., and then it's no longer a  
> small expat dependency only.

Many things are naturally tree shaped most of the time, which avoids
the need to invent names for everything when you don't need to, and
keeps the text compact and clear for human editing.

Otherwise, graph relationships are easily expressed with id="myname"
in one place and ref="myname" in the other place.  (Think like HTML
anchors).  That's useful anyway for clarity sometimes.

> As a user I do prefer easily readable XML formats, like Virtual PC or  
> VMware may use, but I understand that such PC-only formats do not  
> provide enough flexibility to customize a full OF device tree for all  
> the platforms and devices QEMU supports. Having a frontend tool to  
> generate a machine configuration from another config file format  
> seemed like the best compromise when we last discussed the topic.

I don't see what's PC-only about that _style_ of config file, or why
it wouldn't provide the flexibility.

Obviously VMware and Virtual PC's exact format is PC-only, but it
doesn't make sense to mimic them exactly.

-- Jamie