-- Remove calls to fn:zero-or-one if we detect a positional predicate    in its argument.
-- Remove calls to fn:zero-or-one if we detect a positional predicate
   in its argument.

   (Note that we needed to introduce the function call in the type
    checking -- see my yesterday checkin -- because only the core
    optimization (in combination with type information) simplified
    the plans enough to detect simple positional predicates.)

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb