awwx.ws

Creating a parser combinator library to parse JSON

fromjson

fromjson is the entry point into the JSON parser library. It takes a string, parses it as a JSON value, and converts it to an Arc value:

(def fromjson (s)
  (iflet (p r) (json-value (coerce s 'cons))
    (do (if p (err "Unexpected characters after JSON value" (coerce p 'string)))
        r)
    (err:string "not a JSON value: " s)))

arc> (fromjson "true")
t

If the string isn’t a valid JSON value (if the match fails), it raises an error:

arc> (fromjson "fable")
not a JSON value: fable

Questions? Comments? Email me andrew.wilcox [at] gmail.com