XML Catalog issue 16

[John Cowan <jcowan@reutershealth.com>]

# In XML, every external identifier has a system identifier (it may
# also have a public identifier). Delegate processing, as currently
# defined, would effectively discard the system identifier for
# processing the delegated-to catalog. This may not be the right
# thing in XML.

I think it is important to be able to convert 9401 catalogs to
XML Catalogs 1-1, without requiring massive and unfeasible searches
through catalog space.  That requires that 9401 semantics be
preserved exactly.

9401 semantics require that when a catalog has been reached via a
DELEGATE entry, that any SYSTEM entries it contains are of no
effect.  If this property is not preserved, it will be necessary to
split any catalog that *might* be reached via DELEGATE into two
versions, one with and one without SYSTEM.  Keeping these two
in sync would be unreasonably difficult.

Therefore I propose that we not change the existing 9401-compatible
semantics.

-- 
There is / one art             || John Cowan <jcowan@reutershealth.com>
no more / no less              || http://www.reutershealth.com
to do / all things             || http://www.ccil.org/~cowan
with art- / lessness           \\ -- Piet Hein