Pex JSON grammar

json.clj

(def JSON '{json    [whitespace value EOI]

            value (/ string number object array jtrue jfalse jnull)

            object  [(:ws "{")
                     (:join [string (:ws ":") value] ",")
                     (:ws "}")
                     (action capture-object)]

            array [(:ws "[") (:join value (:ws ",")) (:ws "]")]

            string [\" (action clear-sb) characters (:ws \") (action push-sb)]

            number (:ws (capture integer (? frac) (? exp)))

            characters (/ (* normal-character)
                          [\\ escaped-character])

            quote-backslash "\"\\"
            normal-character [(not quote-backslash) any (action append-last)]
            escaped-character (/ quote-backslash
                                 "b"
                                 "f"
                                 "n"
                                 "r"
                                 "t"
                                 unicode)
            unicode ["u"
                     (capture (class hexdigit)
                              (class hexdigit)
                              (class hexdigit)
                              (class hexdigit))
                     (action append-hexdigit)]
            integer [(? "-") (/ [(class digit19) digits]
                                (class digit))]
            digits  [(class digit) (* (class digit))]
            frac    ["." digits]
            exp     [(:ignore-case "e") (? (:anyof "+-")) digits]
            jtrue  ["true" whitespace]
            jfalse ["false" whitespace]
            jnull  ["null" whitespace]
            whitespace (* (:anyof " \n\r\t\f"))})

(def json-macros {:anyof       (fn [str] (apply list '/ (seq str)))
                  :ws          (fn [patt] [patt 'whitespace])
                  :join        (fn [patt sep] [patt (list '* sep patt)])
                  :ignore-case identity})