Re: C.4 Undeclared entities?

>The following information needs to be conveyed, and very preferably in
>a way that SGML can accommodate:

I'm not sure what "SGML can accomodate" means, but if this is used as
a rationale for including meta-data in a document, I disagree.

>(1) that this is an XML document and not a GIF image.
>(2) the character set and encoding of what follows.
>(3) if there is a DTD, what it is called and where to get it
>(4) if there are other auxiliary SGML files, such as SDATA entity definitions
>(5) if there are other auxilliary application-specific files, such as
>    style sheets, navigator/table-of-contents definitions, VRML mappings,
>(7) whether to expect the following data to be a complete document or
>    an incomplete (unfinished partial) document or a reusable a fragment,

>Where there is a standard way of doing something, and that standard
>can be used, use it.

Right. To me this means either MIME headers or catalogs, or a
combination of them both. MIME headers are essentially arbitrarily
extensible, and using them provides a mechanism for file system
storage, email exchange, and HTTP transfer. Catalogs (as defined by TR
9401) are somewhat extensible, and with some *minor* syntax changes
that I recommended long ago, would be arbitrarily extensible.  

Note that the only real difference between MIME and TR9401 is syntax:
they are both essentially just a packing list.

I would say that for the XL specification itself, we only need to
document the *required* information (version, character set and
encoding), and document the assumption that XML systems will provide
some mechanism of tarnsmitting such data. In a seperate document, we
can document the mechanisms used for transmitting such information
(MIME, catalogs).