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Re: New work item for XML group ? (Re: Comments on 31 March spec)

From: Dave Peterson <davep@acm.org>
Date: Sat, 12 Apr 1997 12:09:37 -0400
Message-Id: <v01540b06af754eb1ead3@[199.222.74.239]>
To: w3c-sgml-wg@w3.org
Let's be realistic.  There *will* be cheap 8-bit-internal XML systems.
There *will* be 16-bit-internal systems.  There may be 32-bit-internal
systems.  There may even be non-canonical-internal (e.g., shift-JIS)
systems.

I doubt that XML will prescribe that it is illegal to have an XML system
that cannot represent (and display, else why bother representing) all
the Eastern character sets.

Therefore....

A question we need to address is:  "What should an XML system do when
presented with a numeric character reference for a character for which
it has no internal representation?"

A second question we should be asking is:  "Should XML permit numeric
character references using non-SGML (i.e., undefined in the document
character set parameter) character numbers?"  This determines just how
one should write the document character set parameter for XML's SGML
declaration.  Note:  If they are permitted, how is the system to know
how to handle (e.g., display) them?  How will it "know what the
characters are"?

A related question that SGML generally has to think about, but which
impacts XML is:  "What character is referenced by a numeric character
reference using a  defined-in-the-document-character-set character
number which is defined  to be a "character" represented in a base
character set by a code point that the base character set specifies
to be undefined?"

Dave Peterson
SGMLWorks!

davep@acm.org
Received on Saturday, 12 April 1997 12:11:04 EDT

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