The definition of a procedure may be total
in possible arguments (especially if we count
error signaling as a value of the procedure)
or partial -- leaving it undefined for some
arguments.

Whenever it isn't clear how to make a procedure
total, the first instinct for standards editors
(as opposed to editors) should be to look for
the best way to leave the unclear parts of the
domain unspecified.

That way, successive standards can "climb the
lattice" by filling in the missing definitions
as experience is gained.

-t