From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,1ea92c0e5255811d X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-03-04 14:36:08 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!news-fra1.dfn.de!news-koe1.dfn.de!RRZ.Uni-Koeln.DE!uni-duisburg.de!not-for-mail From: Georg Bauhaus Newsgroups: comp.lang.ada Subject: Re: Way OT: Adam Smith and Software Markets Date: Tue, 4 Mar 2003 22:36:08 +0000 (UTC) Organization: GMUGHDU Message-ID: References: <3vo86vk60e69shjgqdbpp6e5pb8qfop3hr@4ax.com> <87of4qvqhp.fsf@inf.enst.fr> NNTP-Posting-Host: d2-hrz.uni-duisburg.de X-Trace: a1-hrz.uni-duisburg.de 1046817368 3829 134.91.1.15 (4 Mar 2003 22:36:08 GMT) X-Complaints-To: usenet@news.uni-duisburg.de NNTP-Posting-Date: Tue, 4 Mar 2003 22:36:08 +0000 (UTC) User-Agent: tin/1.5.8-20010221 ("Blue Water") (UNIX) (HP-UX/B.11.00 (9000/831)) Xref: archiver1.google.com comp.lang.ada:34879 Date: 2003-03-04T22:36:08+00:00 List-Id: Samuel Tardieu wrote: : For example, you cannot say whether : :
  • List item
  • Second list item
: : is valid in SGML, it depends whether the grammar says that a
  • : closes a preceeding
  • at the same level or not, and whether : closes embedded
  • or not. Yes, and if memory serves right, it also requires the SGML declaration in addition to the DTD, for the parser to known whether or not element type declarations may say something about tag omission etc. Still, XML, being a subset of SGML is not a novelty, which is what I was trying to say; there is no new concept in it, *but* this doesn't mean that it shouldn't have been that neglected in the first place :-) : such as
    . This makes writing parser or transformers much much : easier than their SGML counterpart. There, and only there, lies the : big progress. Yes, a progress for parser writers, but not necessarily for human beings typing markup, or even for people coding of parsing event handlers? Computers should work for humans. (Seems it's often the other way round.) XML is very useful, but where. >From the perspective of a human, writing DTDs and writing XML or SGML documents: Using both a sophisticated validating XML-editor that hides the markup if I want to and two other editors, wily and Emacs+XAE with SGML; sometimes using the latter is much more productive, and I'm glad I can use SGML's minimization features. The outcome is almost pure text; it is a pleasure for the writer to place a end-tag instead of a lengthy , when this name is all too obvious from context. XML can always be produced from SGML input. And like Ada, SGML is not case sensitive, unless requested. A similar comment applies to DTDs: writing these can in cases become really tedious when only the XML subset is allowed; to give just one example: when the "and connector" & is disallowed, as it is in the XML subset, and you want a content model for car choice like (color & motor & comfort), this forces no order where none is needed. XML prohibits this ease of specification. The absence of & is just introduced to make the parser writer's life easier. This is one reason why XML-DTD tools or XML Schema tools are not only helpful, but they are much needed to overcome the restrictions of XML in this case. Otherwise you would have to write ((color, motor, comfort) | (color, comfort, motor) | (motor, comfort, color) | (motor, color, comfort) | (comfort, color, motor) | (comfort, motor, color )) or similar for the exact same thing. So what can smart XML DTD tools do in this case? They can effectively retrofit SGML features onto XML. :-) So, from this perspective, the biggest progress is an opportunity to sell unneded tools to overcome these XML-induced difficulties (I'm exaggerating a lot, and actually XML is _so_ helpful in data transport). -- Georg