tests whether the provided forms are nil
(null? form+) (!null? form+) (is-null form)
If all forms evaluate to null (empty list), then this function will return #t (true). The first non-null will result in the function returning #f (false).
(null? '(1 2 3 4) '())
This example will return #f (false) because the first form is a list.
Like most predicates, this function can also be negated by prepending the
! character. This means that all of the provided forms must not be nil.
(!null? "hello" )
This example will return #t (true).