Hello,
I have found a problem in the specification, which can make usage of
XML more confusing and
in some cases virtually unusable (e.g. when using automatic XML
generation).
There's a bug in the XML specification forbidding double hyphen inside
of commentaries which
is causing unnecessary confusion about XML. The begin of comment is
always <!-- and the
closing of comment is always -->. In this way the double hyphen is
absolutely correct inside
of comments as well as any other character (possibly only characters
defined in the current
encoding)! There's written in the source#1, that double hyphen is
forbidden to stay compatible
with SGML, but look at the following:
In SGML this is correct, but not in XML (used in DOCTYPE):
<!ELEMENT FOO (BAR)*
-- an element FOO that takes any no of
element BAR as its content --
>
Therefore the compatibility with SGML is not met and double hyphen
("--") may be used in XML's
comments without restrictions. Double hyphen will never create a
comment in XML - at least it's
not coded in any known (at least for me) XML parsers. I tried at least
Mozilla, Internet Explorer,
TinyXML and XML Tools from Notepad++. By the way TinyXML does not
forbid double hyphen
inside of commentaries and everything works as expected.
Source: 1) http://www.w3.org/TR/2008/REC-xml-20081126/#sec-comments
-> bug in the specification
2) http://lists.w3.org/Archives/Public/www-html/2002Apr/0060.html
-> discussion about SGML
S pozdravom (Mit freundlichen Gruessen / kind regards)
Michal Stybnar
IT Developer
Siemens Program and System Engineering s.r.o.
SDE-SK SVI
CC PVF BSW
Westend Court, Dubravska cesta 4
845 37 Bratislava, Slovakia
Tel: +421 (2) 5968 4712
SIEMENS E-mail: [email protected]
Internet: http://www.siemens-pse.sk
