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

Re: questions on XML sgml decl's charsets

From: James Clark <jjc@jclark.com>
Date: Tue, 14 Jan 1997 12:18:32 +0700
Message-Id: <2.2.32.19970114051832.00958608@jclark.com>
To: w3c-sgml-wg@www10.w3.org
At 23:11 13/01/97 +0000, Peter Flynn wrote:

>   Let me ask the converse question: is there a rationale
>   *for* specifiying shunned characters?
>
>It makes your editor go BEEP when you try to insert Ctrl-Foo, and your
>parser spew out a line complaining bitterly, thus preventing people
>inserting unwanted bytes by accident or design.

Actually it's not the SHUNCHAR CONTROLS that does that, it's declaring the
control characters as UNUSED (ie NONSGML) in the document character set.
SHUNCHAR doesn't change anything itself directly; it just constrains the
document character set to declare bit combinations as UNUSED unless they are
significant in the concrete syntax.  Adding SHUNCHAR CONTROLS to the XML
SGML declaration wouldn't make any difference. (The SHUNCHAR concept may
disappear in the revision since it does not make a lot of sense in the
context of the new character set model adopted by WG8 for the revision.)

James
Received on Tuesday, 14 January 1997 00:24:30 UTC

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