Re: [Boost-users] serialization-lib add user info to XML format

From: Eduardo Ferro Aldama (eduardo_ferro_at_[hidden])
Date: 2006-07-14 12:17:37

Hi!

Thank very much for the help
I am study the lib implementation, and trying to extend xml_oarchive (as
you
suggest)...

Bye

>I don't know that I can offer you a good solution.  But here is what I can
>come up with.
>
>First a couple of relevant  facts about the serialization library.
>
>a) generally it saves in the archive only that information absolutely
>required
>to be able to recover the data.  This is basad on design/efficiency
>considerations.
>
>b) In some cases it stores "optional" information.  That it is, the
archive
>may be written to save and recover this information.  Normally these
>are just stubbed out as no ops.
>
>c) In xml archives, information about object and class id and their
>references is included in the xml.  I'm don't remember whether its done
>in the "optional" types or not.
>
>c) class name was not considered as one of these optional types
>    i) it wasn't deemed necessary
>    ii) it is not always available. Many types (e.g. primitives) are
>serialized
>without calling the library code.  For these cases the "optional" data
>is not called.
>
>So back to your situation.
>
>What is really needed for you is the following:
>
>a) some sort reflection for C++ so that you can write something like
>t.name().
>b) derive from xml_oarchive to invoke t.name() and insert it into
>the xml stream output.  Examples of deriving from one archive
>type to produce another are in the documentation.
>
>So the problem is "reduced" to making/finding something like t.name()
>which returns a text string which can be inserted into the output stream.
>
>This already exists on one form - the RTTI implementation uses
>type_id(t).name to return a pointer to a name.  This may be sufficient
>for your needs. The only problem with it is that
>
>a) the name will be mangled to a unique C++ name.  This may not always
>be user friendly.
>b) the name will be mangled differently for each compiler.
>
>If you can work with the above limitations - perhaps by massaging the
>mangled name to something readable - this can probably be made to work
>for you.
>
>If not - you can use the name passed by BOOST_CLASS_EXPORT which
>was "invented" to address the issues above.  The only problem is that
>BOOST_CLASS_EXPORT might not bedefined for all your types.
>
>You should have enough here to craft a solution to your problem.
>
>Good Luck
>
>Robert Ramey
>

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