In the psgml.el,v 1.13 2001/02/13, $SGML_CATALOG_FILES
completely override the sgml-catalog-files default
value. The sgml-data-directory, however is
configuration data hard to get at from the outside.
It may be an idea to prefix the files list with the
SGML_CATALOG_FILES (if defined), followed by the
default path. The following snippet does this:
(let ((SGML_CATALOG_FILES (getenv
(concat (if SGML_CATALOG_FILES
To allow users to completely override the path, a
convention similar to the TeX-kpathsearch one could be
used: `A quad-colon ("::") anywhere inserts the default
path in that place'. But that looks like too much
effort for a small gain.