[xsd-users] How to build an object process graph with custom types

[Florian Paul Schmidt]

On 05/11/2011 11:26 PM, Boris Kolpackov wrote:
> Hi,
>
> Bo Ba<bo-ba at mail.ru>  writes:
>
>> This seems to be doable, however, a specific question I have whether
>> it would be feasible to skip building the DOM structure and directly
>> build my custom object graph using xsd.
> Yes, the C++/Parser mapping is designed for exactly this: parsing XML
> and building a custom in-memory representation:
>
> http://www.codesynthesis.com/products/xsd/c++/parser/
>
> Boris
>

Hi folks,

maybe i totally missed something, but oftentimes you have another step 
involved: Building the requested datastructure from the custom in-memory 
representation of the XML document. For my robotics control "framework" 
I chose a way of using a global "type registry" which enables me to 
construct and parametrize the objects needed..

The software is available at github:

http://github.com/fps/CBF

Especially of interest to you might be the xml_object_factory.h:

https://github.com/fps/CBF/blob/master/libcbf/cbf/xml_object_factory.h

Note that for this to work, every type you want to construct from a 
corresponding XML schema type needs a constructor that takes the 
corresponding schema type as argument:

https://github.com/fps/CBF/blob/master/libcbf/cbf/linear_transform.h

Also each type has to create a static global instance of the derived 
factory type in its .cc file, so at library (or application) load time 
this instance is created and registers itself with the base factory 
singleton:

https://github.com/fps/CBF/blob/master/libcbf/linear_transform.cc

This then allows constructed objects to construct its members in turn 
again using this mechanism. See e.g. lines 259ff here:

https://github.com/fps/CBF/blob/master/libcbf/primitive_controller.cc

The corresponding schema can be found here:

https://github.com/fps/CBF/blob/master/schemas/schemas.xsd

Maybe this helps, or maybe it's totally misleading cause i'm a dumba** 
:D I guess the idea is generic enough to be factored out into a library 
on its own..

Have fun and play safe,
Flo