(ql:quickload '("cl-json"))
(json:encode-json
'#( ((foo . (1 2 3)) (bar . t) (baz . #\!))
"quux" 4/17 4.25))
(print (with-input-from-string
(s "{\"foo\": [1, 2, 3], \"bar\": true, \"baz\": \"!\"}")
(json:decode-json s)))