• From: Marcus Reichardt <u123724@g...>
• To: Pete Cordell <pete++xmldev@c...>
• Date: Tue, 8 Mar 2022 08:01:02 +0100


> Am 07.03.2022 um 16:52 schrieb Pete Cordell <pete++xmldev@c...>:
> 
> It does make me wonder why the CDATA section 'directive' wasn't just <!CDATA[...]>.  Even more curious, given all the SGML things that got dropped, is how it got included in XML.  It creates just as many problems as it solves

That I do know ;)

In SGML, not only can you have INCLUDE, IGNORE, TEMP, and RCDATA as status keyword in addition to CDATA, but those keywords could be expanded from parameter entities, like this

<!ENTITY % if_include "IGNORE">
<![ %if_include [ ... blah blah ... ]]>

to conditionally include/exclude content. And moreover, you can use marked sections in the document prolog/in markup declarations, not just in content. Used a lot in DTD construction and modularization where you'd reference an external subset with specifying overwriting ("preempting") values in the internal subset, hence "parameter" entities.

Best,
Marcus Reichardt
sgml.io