Re: [xml] comment syntax

[Liam R E Quin <liam holoweb net>]

On Fri, 2007-05-01 at 19:26 -0500, Mike - EMAIL IGNORED wrote:
> ,
> I see:
>    Comments may appear anywhere in a document
>    outside other markup; ...
>
> Consider:
>
>    <MyDoc>
>       <!--Here is my special tag-->
>       <MySpecialTag>
>          stuff in tag
>       </MySpecialTag>
>    </MyDoc>
>
> Now is a sense, the comment is within markup, being between
> the two MyDoc tags.  I assume that this is NOT what they mean,
> and that the comment is ok.  Right?

Right.  The prohibition is intended to exclude things like
<MyDoc -- this would be an SGML comment but is illegal in XML -->
or,
<!ELEMENT a --* represent the attick of an old house --
   (dirt|rafter|chest)*
>
also legal in SGML but not allowed in XML.

At one point we had <!--* . . . . *--> as an XML comment,
with the asterisks required, but people felt it to be
too verbose.  If we had done this, we could have allowed
"--" inside a comment (with a small change to SGML that
was in fact possible) but as things stand, an XML
comment can't contain "--" at all.

Basically, you can put a comment wherever you can
put an element or (in a DTD or the internal
document type declaration subset) an <!ELEMENT...> declaration.
Do not put a comment before the XML declaration, though,

Liam

-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/
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