Constraints on Attvalues

John Cowan cowan at
Thu Aug 27 17:28:22 BST 1998

Peter Jones scripsit:

> So for my element:
> <myelem   attrib="&ent;"/>
> &ent; can only refer to an internally declared entity, and the literal
> in the entity value, EntValue, cannot contain
>  "....&Another_ent;...." 
> where &Another_ent; is an external general entity.

You are quite right, provided you keep firmly in mind the distinction
between *being* an internal or external entity, and being
internally or externally *declared*.

Internal entities are those whose replacement text appears in the
declaration, and external entities are those whose replacement text
is referenced by a URI or Publicid.  Either kind can be declared
either internally (in the internal subset) or externally (in the
external subset or in an external parameter entity).

It's the first property (*being* an external entity) that is forbidden
in references from attribute values.  External parsed entities can only
be referenced from content.

John Cowan					cowan at
		e'osai ko sarji la lojban.

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