Notations in the external Subset

David Brownell david-b at
Wed Aug 11 17:10:54 BST 1999

Sangineto Stefano wrote:
> <?xml version="1.0"?>
> <!DOCTYPE nachricht SYSTEM "nachricht.dtd" [
> <!ENTITY bild SYSTEM "ferien.jpg" NDATA jpg>
> ]>
> <nachricht>
> ...
> I read in the XML specification that the internal subset is processed before
> the external subset. Is this the reason for my xml-editor error messages
> (Notation not declared Line 3)?

I'd say that's a bug in the validation being performed by
the XML processor used by your editor application.

There's a validity requirement that the notation ("jpg")
be declared.  If you declare it in the external subset,
you'll meet that validity constraint.  The spec doesn't
place a "define before use" requirement there, as was
done for references to parsed entities.

The processor you are using is checking too early (when
the entity is declared); it should be delaying until the
notation declarations are all known.

> Is there a way to get round this annoying problem or must each author
> declare his own notations?

Use an XML processor which doesn't have this bug.

As you implied, it'd be quite painful (also error-prone) to
use unparsed entities if the internal subset couldn't refer
to notations that were declared externally.

- Dave

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