empty - Tests if a string or array is empty.
array empty -> array bool
string empty-> string bool
dict empty -> dict bool
(hello) empty -> (hello) false
empty returns true if the supplied string/array is
of length 0, or the supplied dict has no entries.
/builddir/build/BUILD/nest-simulator-3.3/nest-simulator-3.3/lib/sli/typeinit.sli