some ERB decisions
The SGML ERB met Wed. Oct 16th and voted on several items already
submitted to the SGML WG. Participating: Bosak, Bray, Clark, Maler,
Paoli, Sperberg-McQueen, and Sharpe. Absent: DeRose, Hollander, Kimber,
Magliery, and Connolly. All decisions were by consensus of all those
participating in the call, and thus carry a majority of the membership
of the ERB.
Several issues were left unresolved at the end of the meeting; the ERB
will be meeting today and Saturday to discuss them further and resolve
A.20 XML will retain the notion and syntax of comments (= 8879's
'comment declarations') (7.6, 10.3), but comment declarations
will contain at most one comment: comments will take the form
'<!>' or else will begin with '<!--' and end with '-->' (no
space allowed), and may not contain '--'.
Comments will take the form '<!--' ... '-->', no internal '--' is allowed
and no white space between the final '--' and the final '>'.
Empty comments (<!>) will not be allowed in XML.
B.1 What should XML's character-set rules be? Should conforming
XML documents be restricted to particular character sets?
Should conforming XML processors be required to be able to parse
all conforming XML documents (13.1)?
- the character repertoire of XML documents is that of ISO 10646
- conforming XML documents may be in UTF-8 or UCS-2 form
- all XML processors must accept documents in UTF-8 and UCS-2 (or
optionally UTF-16) form
- XML processor may provide a user option which causes them to accept
documents in other coded character sets (e.g. ISO 8859 or JIS 0208)
or other encodings of 10646 or other coded character sets (e.g.
Extended Unix Code) -- this behavior must be optional (i.e. the user
must be able to turn it off, so that documents not in UTF-8 or
UCS-2 raise errors).
Still open: details of the mechanism to be used for signaling the
encoding and/or coded character set in use.
B.2 Should XML require each document instance to have a DTD or
XML will not require each document instance to have a DTD.
Open question: details of partial DTDs or DTD summaries, if any, and
possible declarations indicating whether the correct ESIS is derivable
for a document its DTD is not read.
B.4 Should XML forbid comments and processing instructions in
mixed content, as a way of simplifying RE handling (7.6)?
Assuming that a satisfactory RE rule can be agreed on, XML will not
forbid comments and processing instructions in mixed content.
B.5 Should XML restrict the use of the PCDATA token in content
models, to simplify RE handling or eliminate the Mixed Content
Problem? (7.6.1, 11.2.4)
* B.5 restrict PCDATA to models of the form (#PCDATA)
* B.6 restrict PCDATA to models of the form (#PCDATA | x ... | z)*
B.8 Should XML use MSOCHAR, MSSCHAR, and MSICHAR strings (9.7)?
B.11 Should XML forbid, allow, or require empty end-tags (7.5)?
-C. M. Sperberg-McQueen
University of Illinois at Chicago