Re: [boost] [Boost Review] Property Tree Library

From: Marcin Kalicinski (kalita_at_[hidden])
Date: 2006-04-21 17:10:41

> Use Serialization lib for this.
>
>> But some values are also only human editable (not on the system setup
>> display etc) so simple XML based files work well because they can easily
>> be read/written by a person and the software itself.
>
> There many ways to deal with it. For example you could keep these fields 
> as strings in memory or use separate storage for them or teach 
> boost::serialization to save/load them.

I have recently tried to do just this. Not subtracting from the great value 
of serialization library, it has a nasty habit of polluting XML files it 
generates with all sorts of magic id numbers that definitly are not human 
editable or creatable. By creating my own archive class I was able to get 
rid of most of them, but not all. Some (class-id integers and tracking-id 
integers) are so inherently embedded in the library that it would require 
quite an effort to hack them out.

To be able to hand-edit XML serialization files, I needed to replace 
class-id integers with class names (the ones you specify to 
BOOST_SERIALIZATION_EXPORT macros). Initially I thought it will be easy, but 
I was wrong. Entire dynamic instantiation mechanism in serialization library 
seems to depend heavily on these integer ids. It only uses names when class 
is first seen, and there is not id for it yet. I then tried to use sure-fire 
method ;-) , which failed as well. Briefly, I made my archive class to 
generate fake class-ids from class names (in an effort to predict which id 
would be expected now by serialization). It failed for reasons I cannot 
recall at the moment - they had something to do with inheritance 
hierarchies.

In case of tracking-ids I just wanted them out, because I do not have 
duplicate objects in human-created files. On the other hand, I couldn't 
disable tracking per-class, because I still wanted other archives to do 
tracking on these objects. A couple of days ago I even posted a question for 
Robert, and he says that I would need to create my own version of 
tracking.hpp.

So as you can see it is not all roses with serialization library and human 
readable files.

Best regards,
Marcin