Parameter entity reference error with expat

Steve Harris (sharris@primus.com)
Tue, 14 Jul 1998 17:57:31 -0700

I'm working out a small DTD by inlining it with some sample data. It
uses a single internal parameter entity and refers to the entity twice
in the DTD. Emacs's 'psgml' seems to validate and do all the
substitutions as expected. If I run the file through expat, though, it
reports the following error:
illegal parameter entity reference

My understanding of the spec. is that a non-validating parser does not
have to expand an external entity, and I could understand that behavior
being applied here, but is it truly 'illegal' to use a parameter entity
reference in this fashion?

Here's a snippet of problematic file:

__BEGIN
<?xml version="1.0" encoding="UTF-8">
<!DOCTYPE options [
<!-- the whole document -->
<!ELEMENT options (head?, macro*)>
<!ELEMENT head ANY>
<!ELEMENT app-name (#PCDATA)>
<!ELEMENT version EMPTY>
<!ATTLIST version
major CDATA #REQUIRED
minor CDATA #REQUIRED>
<!ELEMENT macro (flag|arg)+>
<!ATTLIST macro
id ID
#REQUIRED
argc CDATA "0">

<!-- shared attributes for certain macro sub-elements -->
<!ENTITY % entry-atts
'name CDATA #REQUIRED
presence (inc|exc) "inc"'>

<!ELEMENT flag EMPTY>
<!ATTLIST flag
%entry-atts;> <!-- ** expat quits here ** -->
<!ELEMENT arg (#PCDATA)>
<!ATTLIST arg
%entry-atts;>
]>
<options>
...
</options>
__END

Note that the ATTLISTs for entities 'flag' and 'arg' attempt to expand
an entity called 'entry-atts', for which expat reports an error. I'd
appreciate any assistance in interpreting the spec. here. Is expat doing
the right thing?

Thanks,

Steven Harris
Software Engineer
Primus Knowledge Solutions