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Re: [xml-dev] %x;? - Opportunity for pedantry and exegesis
- From: Joe English <jenglish@flightlab.com>
- To: xml-dev@lists.xml.org
- Date: Fri, 28 Sep 2001 08:34:27 -0700
Christopher R. Maden wrote:
> I concur (though you'd know better than I). I was actually a little
> surprised to note that (foo ?) isn't legal, not even in SGML (see <URL:
> http://crism.maden.org/consulting/pub/sgmldefs.html#[130] >).
I had always thought this was a typo in the spec
(missing a 'ts' between 'generic identifier' and
'occurrence indicator'). As it turns out, it's
specified this way to keep the grammar LL(1);
otherwise there would be an ambiguity at '+'
between occurrence indicators
<!ELEMENT x - - FOO + >
and inclusion exceptions
<!ELEMENT x - - FOO +BAR>
--Joe English
jenglish@flightlab.com