Re: SDD again
> At 06:52 PM 5/8/98 -0700, alex@v... wrote: > >No, it is not false. I hightlighted the word 'safe'. If you absolutely > >*must* know that everything was read and interpreted correctly, you *must* > >use a validating parser. There are many applications where this is not > >an absolute requirement and, thus, you may use a well-formed parser. > > No. This claim is without technical merit and I cannot let it pass > unchallenged. It is trivially possible to achieve correctness and 100% > unquestioned reliability without the use of a validating processor. If you > either (a) construct your DTD so that standalone='true' or (b) don't have > external markup declarations, then you can have NO DOUBT WHATSOEVER that the > document is being parsed correctly, for any sane denotation or connotation of > "correctly". So please stop making this demonstrably false assertion. Hmmm... nothing I am saying is asserting that you can't do (a) or (b). I think the issue is one of verification. If I create an XML document using an arbitrary DTD not authored by me, how do I know how to create a standalone document without using a validating parser? It is the only thing I have that allows me to check that I did everything correctly. (Now, I could do this manually.... but please, what user of XML is going to do that?) Once I have used a validating parser and it passes the standalone=yes validity constraint, I can then send it everywhere I please.... and it should work just fine. > Not only is your premise false in theory, it is vacuous in practice. If you > think, for any real-world application, that its validation against some DTD > guarantees "correctness" in any nontrivial sense, then I don't want to > go anywhere near your software. Validity is a highly specific claim, one > which is of great utility in many applications, but it does not equate to > having "safety" or "correctness". Equally, lack of validity does not > equate to lacking "safety" or "correctness". I did not say this in any way. Validity as defined in XML and all the "safety" or "correctness" that that allows you was only what I was implying. Validity only raises the "comfort level" in which one operates. I can *always* mis-use anyone's DTD at any point in time. > >In addition, there are some applications that need some level of guarantee > >about whether external declaration subsets will be read and honored. It is > >this class of applications that we cannot address today with the current > >definition of well-formed. > > This statement is correct, except for the unnecessary temporizing about > "some level of guarantee". "Guarantee" is a binary condition; if you need > a guarantee that the organization to which you are sending information > will have external declarations read, then you need to specify the use of > a validating processor at that end. If not, then not. Yes. Which is something I have to do external to my document.... which is quite fine with me. > But please don't equate this particular guarantee with general concepts > of "safety" or "correctness" - doing so gives the impression that the use of > documents which are merely well-formed is in some way sloppy or irresponsible; > such a claim is fatuous and very, very, very unhelpful. Ah, now the issue. I am not implying this, and if I did, I certainly did not mean to in any way. This, to me, is an issue of application of the concept of well-formed documents. You must choose at what level you author and processor your content at every step of the way. For example, if you are working within a standardize industry or some partnership-constrainted data transport, you had better use validating processors on the creation and receiving ends. Once a *document* has been identified to be valid, then you may use a well-formed processor. If you are creating an ad hoc document, it seems to me to be perfectly reasonable to only use a well-formed processor. No problem here... XML validity provides you some self-checks. It does not guarantee semantic correctness--which is something I would *never* claim. ============================================================================= R. Alexander Milowski alex@v... (612) 825-4132 v|e|o MOS | sed s/SG/X/g > DYX xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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