W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > April 1997

Re: Error handling: yes, I did mean it

From: Paul Prescod <papresco@calum.csclub.uwaterloo.ca>
Date: Tue, 22 Apr 1997 11:00:37 -0400
Message-ID: <335CD295.174CDC05@calum.csclub.uwaterloo.ca>
To: w3c-sgml-wg@w3.org
Tim Bray wrote:
> 5. Clearly, authoring systems and the like must be able to deal,
>    transiently, with non-well-formed documents.  Is the input subsystem
>    of an editor required to be an "XML processor"?  Why should it?

Is the input subsystem of a browser required to be an "XML processor?"
If not, then your requirement will not have its desired affect.

> That's exactly what I'm trying.  Do you expect malformed PostScript to
> produce a valid page, or a birth-date of September 48th to be accepted
> by a payroll system?

No. But I don't expect that the PostScript standard says that malformed
PostScript must be ignored nor any of the date representation standards
say that invalid dates must be surpressed by the parser.
 
> Another example.  It is very difficult indeed to devise an input
> stream that will cause [gtn]roff to complain.  It is very difficult to
> hand-author any significant amount of PostScript and not have the
> first few drafts thrown out with syntax errors.  Both are successful.

If XML is only going to be hand-authored as often as PostScript is, then
there will be no problem: the editors will handle it.
 
> Sean McGrath again:
> >I was simply making the point that the likes of
> >    nsgmls foo.sgm | grep -c "^(BAR$"
> >can be a useful thing to do even if foo.sgm markup contains errors.
> 
> Sure; but if you replace "grep -c" with some fancy java applet that
> does a business-critical application, this is no longer useful but
> highly dangerous.

Which is exactly why people must have the option to decide for
themselves. They have different applications and different
needs. Hopefully the business-critical application people know how to
capture stderr and know how to pipe to /dev/null if that's what they
decide is best. Let's please leave the whole class of
business-mission-life-critical applications out of this discussion
because those people can take care of themselves. If they can't we
have much bigger problems than well-formedness.

 Paul Prescod
Received on Tuesday, 22 April 1997 10:56:19 EDT

This archive was generated by hypermail pre-2.1.9 : Wednesday, 24 September 2003 10:04:25 EDT