SAX and Attribute value of type ENTITY ?

John Cowan cowan at
Mon Aug 17 16:37:25 BST 1998

Patrice Bonhomme scripsit:

> Ok, so how can i get the corresponding ENTITY value within a SAX application ?

The so-called value of an unparsed entity is simply the data specified by the
URL (or the public identifier).  Its format is specified by the
notation name.

> And i think that the example i gave was not good because the XML Rec says :
> "No External Entity References In Attribute Values".

Your example was valid.  Don't confuse an entity *reference*, which
is of the form "&name;", with the use of the name of an entity as
the value of an ENTITY or ENTITIES attribute.

XML says that entity *references* appearing in attribute values,
like this:

	<FOO bar="this is a &baz; value">

must be internal: "baz" has to be an internal parsed entity, not
an external entity.
> I said:
> ] <?xml version="1.0" ?> <!DOCTYPE foo [ <!ELEMENT foo (#PCDATA)>
> ] 'mydoc.xml'> ]> <foo docref="mydoc">blah</foo>
> If the Entity 'mydoc' was not an External entity (let's say a simple internal
> entity, <!ENTITY mydoc 'mydoc.xml'>)

*That* would be invalid.  In this use, "mydoc" *must* be an external
unparsed entity (there are no internal unparsed entities, of course).

> what should return the SAX driver ?
> 'mydoc' or 'mydoc.xml' ? Could i have something like this : <!ENTITY mydoc
> SYSTEM 'mydoc.xml' NDATA xml> ?

Yes, that is valid.  But the SAX driver will return only "mydoc".

> If SAX returns the name of the Entity, how could i handle entities within a
> SAX application ?

You can declare a DTDHandler to capture the systemid and notation name
of the external unparsed entity.  However, if the entity is declared
elsewhere than in the internal subset, your parser may or may not
read it.  It's up to your application, in the example above, to decide
that "NDATA xml" means this is an XML document, and to parse it.

John Cowan		cowan at
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)

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