[xsd-users] Issue using proxy for Open Packaging Conventions core-properties schema

[Boris Kolpackov]

Hi Rob,

Rob Ursem <Rob.Ursem at cmgl.ca> writes:

> As for the W3CDTF W3CDTF is a SimpleLiteral type which is a _type.

I looked up the definition of SimpleLiteral and it is a restriction
of anyType, which in XSD is mapped to xml_schema::type.


> Neither W3CDTF nor SimpleLiteral provide access to the text
> representation of the element as W3CDTF contains no variables or
> attributes and SimpleLiteral only contains the (optional) lang
> attribute.

Yes, anyType can contain any content (any mixture of text and
elements). In fact the definition of SimpleLiteral is quite
bizarre in that they take anyType and restrict it to only
allowing text content. Why not just use string as a base type
then?


> There are accessors on _type for _node() which would get me to 
> _node()->getTextContent() but the issue is that _node() returns 
> a nullptr for my W3CDTF instance.

This will work if you enable DOM association during parsing. See Section
5.1, "DOM Association" in the C++/Tree Mapping User Manual:

http://www.codesynthesis.com/projects/xsd/documentation/cxx/tree/manual/#5.1


> Perhaps there is an option that allows me to get the raw text for the
> element so I could provide my own interpretation.

Yes, DOM association is that option.


> It seems counter to the philosophy of the library but is that what you
> meant with "customize the generated type"? I can see I can modify the
> generated code but I would rather not since there is the option to
> re-generate it. I haven't tried deriving off the generated code since
> generally the rest of the generated code does not instantiate or use
> the derived code.

No, XSD provides proper support for type customization which doesn't
require you to modify the generated code.

For more information on type customization see the C++/Tree Mapping
Customization Guide:

http://wiki.codesynthesis.com/Tree/Customization_guide

As well as the examples in the examples/cxx/tree/custom/ directory.
In particular, the 'mixed' example shows how to do pretty much what
you want.

Using this approach you could customize the SimpleLiteral type to
contain/return the string you are interested in. Or you could
customize W3CDTF to contain/return a date-time value. Or both.

The advantages of the type customization approach compared to DOM
association is that the client code can use clean API (no need
to know anything about DOM). Plus, it works for both parsing and
serialization (DOM association only works for parsing).

Boris