The following review has been posted through the commitfest application: make installcheck-world: tested, passed Implements feature: tested, passed Spec compliant: not tested Documentation: not tested
Latest patch passes installcheck-world as of d26a810 and does what it sets out to do.
I am not sure I have an answer to the objections being raised on grounds of taste. To me, it's persuasive that GREATEST and LEAST are described in the docco as functions, they are used much like variadic functions, and this patch allows them to be used in the ways you would expect variadic functions to be usable.
But as to technical readiness, this builds and passes installcheck-world. The functions behave as expected (and return null if passed an empty array, or an array containing only nulls, or variadic null::foo[]).
Still no corresponding regression tests or doc.
The new status of this patch is: Waiting on Author
I wrote doc (just one sentence) and minimal test. Both can be enhanced.