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From Stefano Mazzocchi <>
Subject Re: [status & RT] design challenges
Date Mon, 08 Apr 2002 09:55:52 GMT
Uli Mayring wrote:
> On Fri, 5 Apr 2002, Stefano Mazzocchi wrote:
> > I'm perfectly aware of the fact that components must pass information
> > one another, but, why in hell should they use something so ackword as
> > SAX events to write and XPath queries to read when they can simply do an
> > hashtable lookup?
> Good point. But, if I may ask, why have different communication protocols
> at all? 

Perfectly agreed. In fact TCP/IP showed you don't need more than a good
one. :)

Have you seen BLOAT? it's an april fool's RFC about 'TCP/IP over XML'.
It's a *very funny* read (don't remember the RFC right now).

My impression is that we are doing the same thing here as well.

> I can think of many practical reasons (performance,
> maintainability etc.), but from an architectural point of view it only
> makes sense if there are different concerns and different users. We tailor
> the communication protocols to the task and to the audience.

> But can it be that the audience for meta-information and SAX events is the
> same?

This is a good question, but I personally don't think so.

I mean: from the use cases that were proposed about pipe-aware
selection, the selection was almost always performed on 'augmented data'
inserted by a transformer right before selection.

This 'augmented data' is, almost always, metadata that drives the
further selection.

It's clearly a communication between a direct component (acting 'in' the
pipe) and an indirect component (acting 'on' the pipe).

Passing information from direct to indirect components 'inside the pipe'
it's, IMO, wrong and unnecessary.

Stefano Mazzocchi      One must still have chaos in oneself to be
                          able to give birth to a dancing star.
<>                             Friedrich Nietzsche

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