(defun parse (input)
  (nyala:parse (input)
    (document -> (++ :sep value) (? :sep) => `(document ,@$1))
    (value -> (or :number :symbol array object string))
    (array -> "[" (* :sep) (? (++ :sep value) (? :sep)) "]" => `(array ,@(second $3)))
    (object -> "{" (* :sep) (? (++ :sep value-pair) (? :sep)) "}"
            => `(object ,@(alexandria:mappend #'identity (second $3))))
    (value-pair -> value :sep value => `(,$1 ,$3))
    (string -> verbatim-string)
    (verbatim-string -> :line => `(verb ,$1))
    (:line -> '"|" (= it (- (* t) #\Newline)) :eol => it)
    (:number ->
             (? #\-)
             (or #\0 "[1-9][0-9]*")
             (? "\\.[0-9]+")
             (? "[Ee][+-]?[0-9]+")
             => (let ((*read-default-float-format* 'double-float))
                  (read-from-string $$)))
    (:symbol -> "[A-Za-z+_][A-Za-z0-9-]+" => (intern $$))
    (:sep -> (+ (or #\Space #\Tab #\: #\, #\Return #\Newline)))
    (-> (or #\Space #\Tab #\: #\, #\Return #\Newline))))

(parse "-1234.32e1 hello 1234 [ what bobby ] { hoho there 1234 444 } [
] { }
| hi there
| what is
[]")

;; =>
(DOCUMENT
 -12343.2d0 |hello| 1234 (ARRAY |what| |bobby|)
 (OBJECT |hoho| |there| 1234 444) (ARRAY) (OBJECT)
 (VERB " hi there
| what is")
 (ARRAY))