correct behaviour for entities as system identifiers

[Warren Hedley <w.hedley@auckland.ac.nz>]

Hi folks,

The short story is:

The CellML ( http://www.cellml.org/ ) DTD, which makes use of the MathML
DTD, includes the following code:

1 <!ENTITY % use_mathml_dtd "IGNORE">
2 <![%use_mathml_dtd;[
3   <!ENTITY % mathml-charent.module "IGNORE">
4   <!ENTITY % mathml_dtd_path "'MathML-20010221/mathml2.dtd'">
5   <!ENTITY % mathml_dtd PUBLIC "-//W3C//DTD MathML 2.0//EN"
6      %mathml_dtd_path;>
7   %mathml_dtd;
8 ]]>

The Xerces parser reckons that "The system identifier must begin with
either a single or double quote character" on line 6, which I take it
means that it regards the apostrophes in the mathml_dtd_path entity
as just plain characters. Is this the correct behaviour?

The long story is:

Michael Kay's Aelfred parser, XP 0.5, and SP 1.3 all let this one
through and behave as expected.

If it wasn't already obvious what I was trying to do, I would like
to be able to have an entity that I can use to set the path to the
MathML DTD in a particular document's internal subset, if different
from the one specified there.

Thanks,
Warren Hedley

-- 
Warren Hedley