(assert (= "abc" (append "ab" #c)))
(assert (= "abcd" (concat "ab" "cd")))
(assert (= "bc" (slice "abcd" 1 3)))
(assert (= #c (sget "abcd" 2)))
(assert (= 3 (len "abc")))

(assert (string? "asdfsdaf"))
(assert (char? #c))
(assert (symbol? 'a))