(examples-for empty?

("nonzero"       (empty? "foo-bar")  nil)
("zero"          (empty? "")         t)
("blank"         (empty? "  ")       nil)
("nil is t"      (empty? nil)        t)
("sym is nil"    (empty? 'abc)       nil)
("number is nil" (empty? 234)        nil)

("nil for proper list"     (empty? '(a b))            nil)
("nil for improper list"   (empty? '(a b c . d))      nil)
("t for empty hash"        (empty? { })               t)

("nil for hash with keys"
 (empty? { a 11 b 22 c 23 d nil e { nested t counted nil } })
 nil))

(examples-for present?

("nonzero"       (present? "foo-bar")  t)
("zero"          (present? "")         nil)
("blank"         (present? "  ")       t)
("nil is nil"    (present? nil)        nil)
("sym is t"      (present? 'abc)       t)
("number is t"   (present? 234)        t)

("t for proper list"       (present? '(a b))            t)
("t for improper list"     (present? '(a b c . d))      t)
("nil for empty hash"      (present? { })               nil)

("t for hash with keys"
 (present? { a 11 b 22 c 23 d nil e { nested t counted nil } })
 t))