A different comment syntax question

Chris Maden crism at oreilly.com
Fri Jul 17 18:18:50 BST 1998


[Rob Cameron]
> Although the XML specification makes clear that "--" is not allowed
> in comments, there is another case that is less clear.  Can the body
> of a comment end in a single hyphen, that is, is a comment like
> "<--A+, A or A--->" legal?  There is no explicit mention of this in
> the text of the specification, but a careful read of the grammar
> does not allow it.

Correct.  The production reflects the SGML reality that -- ends a
comment.  In SGML terms:

'<!'         starts the comment declaration in your example.
'--'         starts the comment.
'A+, A or A' is the content of the comment.
'--'         ends the comment.
'-'          is an error.
'>'          could be considered to end the comment declaration, but
             we're now in error-recovery mode, and outside the scope
             of the specification.

<!--A+, A or A- --> is a legal comment.

-Chris
-- 
<!NOTATION SGML.Geek PUBLIC "-//Anonymous//NOTATION SGML Geek//EN">
<!ENTITY crism PUBLIC "-//O'Reilly//NONSGML Christopher R. Maden//EN"
"<URL>http://www.oreilly.com/people/staff/crism/ <TEL>+1.617.499.7487
<USMAIL>90 Sherman Street, Cambridge, MA 02140 USA" NDATA SGML.Geek>

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