On Tuesday 22 January 2002 12:28, Tod Harter wrote: > Well, as a guy that has done a lot of work in software systems design and > in data processing architecture my humble opinion is that you should look > at the XML model as in some ways parallel to an OO system.
Ah, now I see where you come from, but imho your angle, while not "wrong" is only one angle. XML _can_ be seen as an OO system, but it is by no means necessarily that. XML is also data, is also documents. There is a well know mismatch between OO typing and data/document typing as can be seen in various problems that have surfaced relative to XML Schema, to databases, to the DOM. > The fact that the people that defined XML in the beginning called PIs > "hints" is irrelevant. XML processing has grown far beyond what was > originally envisioned. That terminology and method of thought originated in > the world of document management and styling, not application type > processing. But tell me, why should I not care about what the people that originally defined XML thought, yet care about what you and some others think ? ;-) I don't disagree with the fact that you're free to use PIs whichever way you want. In fact, that is precisely what I defend. If _you_ want to use PIs as class declarations (something that wouldn't even cross my mind, I'd use namespaces for that) then fine, use them as such. I want to use Processing Instructions to.... give instructions to a processor. I tell my browser or SVG viewer (or whatever renderer) that it ought to use CSS file foo to show the file: "Process it thus". If another processor comes along (say, one that extracts all the info I've hidden outside the SVG namespace in my SVG file) I don't want it to see the PI, or to care about it. Similarly, if I have a view source in my SVG viewer, I don't want it to try to style what it's showing me :-) So what I disagree with is your "my approach is right, all others are wrong or at best kludgy" slant. Some of us want to use PIs as PIs, what's wrong with that? PIs are information items, that sometimes you may want to use, sometimes not, depending on context. Say I have a meatsub.xml document, that has a <?served-with sauce='thick and hot'?> PI. What's wrong with the following hypothetical Apache configuration: <IfDefine onDiet> AxProcessPI served-with no </IfDefine> ? > As a plus XML gives us the option to use "alternate stylesheets" which we > can think of as a mechanism for providing a sort of "overloading" of > certain operations when appropriate. There is no exact equivalent in an OO > system paradigm, but in some ways it is much like in OO perl where you can > bless the same fundamental data type into one or more different packages > depending on your needs. Alternate stylesheets are another option, but that's where I start to think things look klunky ;-) -- _______________________________________________________________________ Robin Berjon <[EMAIL PROTECTED]> -- CTO k n o w s c a p e : // venture knowledge agency www.knowscape.com ----------------------------------------------------------------------- Oops. My Brain just hit a bad sector. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
