Re: [boost] [serialization] Enhancing Archives with Archve Adaptors

From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-11-27 13:33:53

Robert Ramey wrote:

> Just to speculate on an imaginary example - please don't treat
> this as a serious proposal which I have to defend.  Suppose
> someone comes along and looks at the xml_archive.  He says
> wow - now that is way cool - But its really not done.  What I
> need is to create an xml schema along with with my xml_archive
> so i can use my xml wizebang tool to browse and maybe
> edit my archive!.  [...]

[...]

> Here is the key point.  I'm not really concerned about specifically
> about save_array.
>
> The save_array optimization is one example of any number
> of enhancements and/or extentions that people might want to
> make.  But it is not the only example.  We can't go mixing
> every great idea into the core library without running into
> an intractible scalabilty problem.

True. But there is a fundamental difference between your enhanced archive
examples and array serialization.

One function of the library is to act as a mediator between programmers that
write serialization functions for their types and programmers who implement
archives. The library provides a common language so that these two groups of
programmers can communicate without ever having to coordinate their efforts.

When the author of X that has two fields x and y wants to serialize it into
_any_ archive, he just "says" save(x) and save(y) to the archive.

However, the author of Y that contains an array currently can't just say
save_array(a) to the archive, because save_array is not part of the current
vocabulary. He needs to say save(a[0]), save(a[1]), ..., save(a[n-1]).

This works, but it makes it needlessly complicated for the archive to detect
that it is being fed an array, rather than a sequence of ordinary save
calls.

In contrast, the "someone might want to do..." enhanced archive examples do
not involve communication between these two groups of programmers. The
programmer of the archive just decides to implement a specific format and
that's it.