Re: ISO/IEC 10646 as Document Character Set

Glenn Adams (glenn@stonehand.com)
Sun, 7 May 95 13:28:48 EDT

Thanks for your clarification. I have two more questions:

1. What kind of error should be reported upon an occurrence of a numeric
character reference which contains a character number which *is not*
described by the document character set? Should this be treated as
an occurrence of a non-SGML character or as something else entirely?
In particular, should it be treated as a reportable markup error or
as an "other error" according to 15.4.1?

2. What kind of error should be reported upon an occurrence of a numeric
character reference which contains a character number which *is*
described by the document character set (by reference to a base set
character number) but which *is not* described by the system character
set? Or which is decribed by the (formal specified) system character
set but which has no bit combination in the (actually implemented)
system character set?

I may be misreading it, but the text describing the requirements for the
system character set seems to be weaker than for the document character set:

15.6 line 29f.

"The system character set must include one and only one coded repre-
sentation, that is, a single bit combination, for each significant
^^^^^^^^^^^^^^^^^^^^
SGML character in every concrete syntax described by the concrete
^^^^^^^^^^^^^^
syntaxes supported parameter."

It may be that lines 22-24 require that the system character set
describe all character numbers which are described by the document
character set:

A system declaration must meet the same syntax requirements
as an SGML declaration with respect to the concrete syntax used,
data characters allowed, etc.

Yet lines 29-33 seem to admit to the possibility that the system
character set need not contain bit combinations for all characters
(i.e., for non-significant SGML characters).

A Wandering Supplicant in the Wilderness of Characterhood,
Glenn Adams