- From: Len Bullard <cbullard@HiWAAY.net>
- Date: Tue, 15 Oct 1996 07:57:07 -0500
- To: James Clark <jjc@jclark.com>
- CC: Bill Smith <bill.smith@eng.sun.com>, w3c-sgml-wg@w3.org
James Clark wrote: > > At 18:21 14/10/96 -0700, Bill Smith wrote: > >Len Bullard wrote: > > > >> 3. Is the processing time severe for the case you state? > >> I realize this question has many hands to argue with. > > > >While the average case time may not be "severe", the worst case behavior > may be > >and therefor cannot be ignored. > > > >If an empty element is inserted high in a document instance (say an <A> > within a > >high-level <DIV> in HTML 3.2), the emptiness of <A> cannot be inferred > until the > >enclosing element is closed - or the parser performs lookahead. Either way, > >processing is delayed and application complexity increases. > > Isn't the problem even worse than this? You don't just to figure out that > empty elements are in fact empty, you also have to figure out that non-empty > elements are not in fact empty. The first time I see a chapter tag, I can't > tell that it is not in fact an empty tag until I see its close tag. So > either I can't start displaying the chapter until I have got the whole > chapter or I have to assume initially that every tag is non-empty and be > able to go back and reformat when I discover one that's not. This just is > not going to work. > > James But it is working. It requires the DTD and in cases for systems that already do SGML as hypermedia, it has required a stylesheet where a DTD was not used. I see the point of avoiding lookahead that it adds complexity, but in fact, empty elements are used successfully and they work. In the cases I'm thinking about, IDE/AS and IADS they don't format as they load, but many of these documents are considerably bigger than the average Web page and the performance is acceptable. I think you overstate. The <e></e> looks worse than <@e>. It is consistent, but intuitively wrong. As I said, do as you will, but be prepared to explain it repetitively. len
Received on Tuesday, 15 October 1996 08:56:54 UTC