[xsd-users] Preserving XML element order

[Boris Kolpackov]

Hi Barrie,

Barrie Kovish <barrie.kovish at singularsoftware.com> writes:

> I am reading an XML file in and writing it out using classes generated 
> by XSD.  In general I need to make a few simple modifications to the XML 
> file. But even if I don't modify the XML file the order of the elements 
> is not preserved.  i.e. if the XSD classes read in
> 	...
> 	<X>1</X>
> 	<Y>2</Y>
> 
> The XSD classes might write out 
> 	...
> 	<Y>2</Y>
> 	<X>1</X>

There are certain XML Schema use-cases where this can happen due to the 
flattening of the compositor structure in the C++/Tree mapping. For 
previous discussions of this issue see:

http://www.codesynthesis.com/pipermail/xsd-users/2008-May/001697.html
http://www.codesynthesis.com/pipermail/xsd-users/2008-June/001739.html


> This is a big problem for me because the program which uses these XML 
> files is sensitive to the order of the elements.  Note that the schema 
> does note impose an order on the elements and the program which 
> generates the XML files does not order the elements in a specific way.
> However it is important for a specific document that the order not 
> change.

Can you show the relevant schema fragments? 


> Is there a solution to this?

There are several ways in which this can be worked around. But I will
need to see the schema to be able to make a suggestion. 

There is also the C++/Hybrid[1] mapping in XSD/e[2] which recreates the
compositor structure precisely and preserves the element order in all
cases. While XSD/e was designed primarily for mobile/embedded systems,
if configured to use STL, etc., it can also be used in general-purpose
applications.

[1] http://www.codesynthesis.com/products/xsde/c++/hybrid/
[2] http://www.codesynthesis.com/products/xsde/

Boris