Ahoj Jozef,
this is not a bug, XML parsers are not supposed to distinguish between
the two, see:
http://www.w3.org/TR/REC-xml/#sec-starttags
"[Definition: An element with no content is said to be empty.] The
representation of an empty element is either a start-tag immediately
followed by an end-tag, or an empty-element tag."
As for the serializer: element with an empty text node is serialized
with a pair of start and end tag rather than an empty tag in conformance
with this non-normative recommendation (same document):
"For interoperability, the empty-element tag should be used, and should
only be used, for elements which are declared EMPTY."
AFAIK, the serializer in libxml2 does not look into the DTD at all, but
the presence of a text node (although empty) on the element node
suggests that the element is not declared as EMPTY and therefore it
should not be serialized using an empty tag. On the other hand, an
element with no content at all looks as an EMPTY element and the
serializer therefore chooses to serialize it using an empty tag.
Best,
-- Petr
On Wed Nov 11 08:33:37 2009, JKUTEJ wrote:
Show quoted text> Hi Peter,
>
> $ perl -MXML::LibXML -le 'print
> XML::LibXML->new()->parse_string("<VALUE></VALUE>")->toString'
>
> output:
>
> <?xml version="1.0"?>
> <VALUE/>
>
> $ perl -MXML::LibXML -le 'print
> XML::LibXML->new()->parse_string("<VALUE/>")->toString'
>
> output:
>
> <?xml version="1.0"?>
> <VALUE/>
>
> When generating these are two different cases:
>
> perl -MXML::LibXML -le '$d=XML::LibXML::Document->new("1.0", "UTF-8");
> $e=$d->createElement("VALUE"); print $e->toString;
> $e->addChild($d->createTextNode("")); print $e->toString'
>
> output:
>
> <VALUE/>
> <VALUE></VALUE>
>
> Now I'm not sure if this is a bug, but I think the parser should make
> the difference between <VALUE/> and <VALUE></VALUE>. In the first case
> there should not be any child element, in the second case there should
> be one child text node with empty string.
>
> Cheers,
> Jozef
