Re: bohemians, gentry
Uche Ogbuji: > [...] > |> Or have I missed the point? > | > | I think you may have missed the point, because as far as I see it, you're > | using data types in a very modular fashion: i.e. at the precise point in > | processing where it is immediately useful. > | > | I think that no one objects to such use of data types. Norman Walsh: > Who or what is preventing you from using them that way? (I'm really > not trying to be argumentative, I think I'm a bohemian myself, and I > sometimes think the gentry go a little bit off the rails, but I don't > lose sleep over it because I don't see how I'm being threatened. As I > said before, maybe I'm insufficiently paranoid.) So read on... > | The problem I bring up is that in their very tight coupling to text-based XML > | processing specs, that WXSDT end up pretty much imposing implicit data typing > | even when it is not needed, and when it can hamper the processing. > > Where is the tight coupling? Schema import into a stylesheet or XML > Query will bind them together, but I think that's an instance of > modular use. That doesn't bind my documents to any particular schema > (except perhaps when I run a particular query, naturally). Two things: 1) From my last reading of XPath 2.0, schema "import" was not optional if the document had a PSVI. If this has changed, this is a big step forward. 2) Even if schema import is optional, it is all or nothing. More likely, I want to use type information in, say, one template, and not across the board for all values. So I (possibly) have tight coupling, and too clumsy granularity. Both are problematic, and don't correspond to modularity for me. > | In order > | to use these new data typing "wizards" (as Jonathan call them, seemingly > | deadpan), you have to build these data types into the schema or the instance, > > Building data types into the schema doesn't seem harmful. That's the > point of a schema, is it not? My point is that it ensures tight coupling. > I'm not sure what you mean by building the data types into the > instance. If you mean using xsi:type, Yes. That's what I mean. > then I agree completely that > it's brittle. And wrong. And I'll quickly discard any tool that does > it. I'm curious: Why do you think it is more wrong than building it into the schema? Not that I disagree... > | which means they now affect all XPath, XSLT and XQuery operations on them. > | This, I think is where the brittleness emerges. > > Sometimes I write stylesheets that are entirely data type agnostic, > but not really very often. I don't see how building data typing into a > particular stylesheet or query is harmful. I didn't say building it into a particular stylesheet or query is harmful. I said that if the data typing info in the PSVI is used at the basic XPath processing info, that this is harmful, except in skilful hands. > | * The lack of modularity in W3C efforts to incorporate data typing into XML > | technologies > > Do you mean because they're tied more-or-less exclusively to WXS? Or > do you mean something else? Bound to PSVI, to be specific. And I also mean that there hasn't been enough work in defining profiles that define generic processing (including constraints processing) for those who don't want static typing. > | In other words, to return to trope: I dislike the fact that things are > | permanently stamped with their class for all their lifetime, and that their > | class is considered an intrinsic part of their being. That's so, like, fuedal. > > What is "all their lifetime"? If I drag a stream of bits off my disk, > subject it to schema validation, and build, for example, an XPath2 > Data Model instance out of it, those types will be stamped on the data > model. But the chances are pretty good that I'm going to use that data > model to do some particular process on the document and then throw it > away. Maybe. I didn't say that it is impossible to use data types soundly. -- Uche Ogbuji Fourthought, Inc. http://uche.ogbuji.net http://4Suite.org http://fourthought.com Tour of 4Suite - http://www.xml.com/pub/a/2002/10/16/py-xml.html Proper XML Output in Python - http://www.xml.com/pub/a/2002/11/13/py-xml.html RSS for Python - http://www-106.ibm.com/developerworks/webservices/library/ws-p yth11.html Debug XSLT on the fly - http://www-106.ibm.com/developerworks/xml/library/x-deb ugxs.html
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