Re: C.14 Enumerations in attribute declarations?
On Thu, 17 Oct 96 13:32:27 CDT, Michael Sperberg-McQueen
>On 23 October 1996, the ERB will vote to decide the following
>question. A straw poll indicates the question needs further
>discussion in the work group. Possible positions are to remove
>8879's restriction (at the cost of more complex XML-to-SGML
>DTD translation), to retain it, to eliminate enumerated values
>entirely in the hope that WG8 will relax the restriction, or
>to retain the restriction but make it a non-reportable error.
>C.14 Should XML allow more than one enumerated type (name-group
>declared value) to contain the same possible value (11.3.3)?
WG8 has agreed to remove this restriction in SGML97.
However, I think the right solution for XML is to eliminate enumeration on the
grounds of simplifying attribute definitions. I'd dump all of the tokenized
values for the same reason, except those that have SGML semantics that we are
retaining in XML (possibly ID, IDREF, IDREFS, ENTITY, ENTITIES, and NOTATION).
The SGML Extended Facilities, which WG8 have voted to incorporate in SGML97,
have a lexical typing facility for data content and attribute values using
regular expressions and other goodies. Why burden XML with the existing half
measures? Keep things simple for XML 1.0 by sticking to CDATA and add clean
lexical typing later.
Charles F. Goldfarb * Information Management Consulting * +1(408)867-5553
13075 Paramount Drive * Saratoga CA 95070 * USA
International Standards Editor * ISO 8879 SGML * ISO/IEC 10744 HyTime
Prentice-Hall Series Editor * CFG Series on Open Information Management