A special symbol is reserved to indicating a Json null value. A parsed Json graph follows the naive recursive data structure definition as Json is a string, number, boolean true or false , list of Json or an object with a multiplicity of unique symbol labeled Json.
JsList : Listof Json. JsNull : ' JsNull. JsNull - : JsObject. JsNull cat. Note: For boolean values attributes, given how Option values are implementinted in Typed Racket, the f return value cannot be used to descriminate between an existing attribute whose value is f or a missing attribute.
By design JsObjects are currently implemented as mutable hashmaps and may be mutated. Recall that a JsObject is a type alias for a Racket mutable hashmap. For details concerning concurrent modification see the Racket documantation for hashmaps.
The Racket implemetation of hashmap operations is rich and only a subset are currently wrapped in this library. Additional capabilities such as union, jsobject-union! JsNull - : String. A translation of a parsed Json data structure reflectiing it recursive nature. A define-type alias reflecting a Json Object as a hashmap of symbols and Json values.
A Json null value is reflected in Racket as a special reserved symbol. JsNull is a define-type alias for the symbol value at the type level. In Typed Racket each symbol is given a unique type containing only that symbol. Creates a JsObject instance from a list of symbol and json value associations. Note as a JsObject is just a transparent type alias for a HashMap any of the standard Racket hashmap construction procedures maybe used as well such as hash JsNull - : JsObject ' hasheq dog.
