- From: Andrew Layman <andrewl@microsoft.com>
- Date: Tue, 15 Jul 1997 21:10:22 -0700
- To: Sam Hunting <sgmlsh@CAM.ORG>
- Cc: w3c-sgml-wg@w3.org, lee@sq.com
Unless you mean this as some sort of reference to Positivist philosophy, I think the meaning is clear: XML is a subset of SGML. If something is valid XML, then it is valid SGML. This has nothing to do with how such validity is tested, it is a simple statement of fact regarding the two notational systems and the relation between documents conforming to the rules of each. > -----Original Message----- > From: Sam Hunting [SMTP:sgmlsh@CAM.ORG] > Sent: Tuesday, June 24, 1997 7:57 PM > To: lee@sq.com > Cc: w3c-sgml-wg@w3.org > Subject: Re: Meaning of normative references [was: Update on > namespaces] > > [Taken as read: fulsome commendation to *both* Len and Dan for > effective > use of rhetoric.] > > > Instead, we should have a note that says that every valid XML > document > > will ipso facto conform to ISO 8879, and possibly refer the > interested > ^^^^^^^^^^ > > reader to that document. > > Meaning: "By that very fact" (as opposed to ipso jure "by the > operation of > the law itself", says the OED.) > > But how is this "fact" to be tested? (It's like saying "every bottle > of > beer ipso facto contains 4% alchohol", when there's no way of actually > testing specific gravity for a reality check on any given bottle.) > > Ipso facto validity will come down, in practice, to validation by the > XML > parser at hand. ("Feels like 4% to me!") > > > cannot be a normative requirement for XML conformance. Rather, the > > XML spec must stand alone, but the resulting valid XML documents > must > > ^^^^ > > always be valid SGML documents. So any reference to SGML in the XML > > spec must be for interest, not one that forces people to read ISO > 8879:1986. > > Again, how "must" (and why not "shall"?) > > Would it be possible to move to "ipso jure" xml validity by > introducing > the concept that SGML is "operationally normative" with respect to > XML? > > By "operationally normative" I mean: a free and technically excellent > SGML > parser (say, nsgmls) is set up at a sensible site (say ...). The > location > of the parser and the command line to supply it are published in the > XML > specification. Then, if someone (say, a contractor who is obligated to > produce SGML-valid XML, or the grad student at the end of his/her > one-week > trek) can feed that parser the XML in question, and if there are no > errors, the XML is SGML. > > Returning to the beer metaphor, under this proposal the person with > the > bottle in hand doesn't have to read a physics textbook to test that > the > beer is 4%. > > S. > > P.S. Incidentally, Len is correct that if the XML specification does > what > it says it does (that is, if the words "Valid XML documents are SGML > documents in the sense described in 8879" are true in reality as well > as > intent), no one will ever have to read actually read the SGML > standard, > because no need for clarification will ever arise, and the XML > specification will be able to stand alone. > > But that is asking humans (the ERB, us) to create a perfect > specification > -- not possible in this world, no matter how well anyone "does their > job." > Therefore, some method of allowing SGML to be normative ipso facto and > ipso jure is necessary that does not require the standard to be read > is > needed: why I propose the concept of "operationally normative." >
Received on Wednesday, 16 July 1997 00:10:25 UTC