SGML declaration for XML

[Rick Jelliffe]

From: Stefan Mintert <mintert at irb.informatik.uni-dortmund.de>


>What is the correct SGML declaration for XML?

The correct one is:

<!SGML -- SGML Declaration for XML --     "ISO 8879:1986 (WWW)"


    This is the 1997 extensions of SGML for the WWW: character ranges
    in names, hexadecimal character references, and white-space handling.
    (Parsers in) SGML systems before made before 1998 will not support
    these extensions.

<!SGML -- SGML Declaration for XML --    "ISO 8879:1986 (ENR)"

    This is the 1996 extension to SGML: it allows character ranges only.
    (Parsers in) SGML systems made before 1997 will not support this
extension.
    XML can still use this: but you will want to use decimal numeric
character
    references only. You must have a DOCTYPE declaration.  The parser
    must support NET-enabled tag minimization, to cope with <x/> tags,
    otherwise just use <x> for EMPTY element types.
    "ISO 8879:1986 (ENR)" is transitional only.


Finally <!SGML  "ISO 8879:1986"

    This is traditional SGML. XML can still use this: but you will want to
use
    decimal numeric character references only, and restrict yourself to
    less than 60 name characters more than ASCII. You must have a
    DOCTYPE declaration.  The parser must support NET-enabled
    tag minimization to cope with <x/> tags, otherwise just use <x> for
    EMPTY element types.

>(2):


>  a Name may start (NAMESTRT) with a ':'


All uses of ":" are still experimental.  Starting  a name with ":" would
presumably
be done to implement some scoping. In general, XML has avoided anything
which makes parsing or understanding a name depend on context--it has a
terrible complicating effect. (Note however, that attribute and data values
are full of context-dependent connotations.)

My understanding is that the namespace proposal is currently not
intending to allow ":" to prefix names, but you should ask the WG people
for some confirmation: (Tim?)

Rick Jelliffe


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