Re: [boost] RE: Serialization Library Review

[Beman Dawes]

At 12:51 PM 11/17/2002, Robert Ramey wrote:

>From: "Peter Dimov" <[EMAIL PROTECTED]>
>
>>> I'm really interested in the XDR format, not because I care about the
>>> format itself, but because others seem to use it as some sort of litmus
>>> test for serialization libraries. Thus knowing that Robert's library
>>> handles XDR well is of interest.
>
>>FWIW, in my experience, XML is a better test for whether a serialization
>>library handles custom formats well. Sequence-based, header-only formats
>are
>>very similar, but a reasonable XML serializer creates a tree-like
>>representation, with nested tags.
>
>After a cursory investigation as to what it would take to make an XML
>archive, I've concluded that:
>
>a) I don't thing XML is rich enough to capture all possible C++ data
>structures

Uh... I think one of us must be misunderstanding something about XML. If you can represent serialization of some objects as a character based file, can't you turn it into dumb XML by wrapping it in <my_dumb_tag>....</my_dumb_tag>? Perhaps you mean you don't think it is possible to define a set of tags that themselves are rich enough to capture all possible C++ data structures?

But so what? You can just supply content directly for any C++ structures that don't represent well in the XML tagged style. And we know from experience that many C++ data structures can be usefully represented in an XML style format.

>b) This would imply the creation of a system of reflection for C++
> i) I not convinced this is a good idea
> ii) should be dealt with as an indepent project in any case
>
>c) XML has a central task to represent data in a platform/programming
>language
>independent way. Serialization has the central task of saving/restore the
>totality of the state of C++ data structures. These tasks are not
>identical
>and any course of action based on the presumption that they are is
>doomed to be frustrating an most likely a failure in my opinion.

That seems a rigid view of XML. Just think of it as a way to markup the output you are already producing to make it a bit easier for other tools to work with. Some of the whitespace or other delimiters become tags. If the output you are already producing captures various C++ data structures, adding XML markup just enhances the already captured data. That's probably a dumb way to use the power of XML, but it may be sufficient for serialization needs.

On the input side, I don't think anyone was suggesting being able to parse the full generality of XML, but just to be able to take in the exact markup that was previously output.

--Beman


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