JSON encoder and decoder

Author(s): Jose F. Morales.

Stability: [devel] Currently the subject of active development and/or research. Functionality may be limited and API and/or functionality may change without warning or deprecation period. Not recommended yet for use in production.

This module defines a term representation for JSON (JavaScript Object Notation), as well as encoders and decoders.

Usage and interface

Library usage:
:- use_module(library(pillow/json)).
Exports:
- Predicates:
  json_to_string/2, string_to_json/2, json_get/3, json_get_atm/3, atomiclst_to_json_strlist/2, atomic_to_json_str/2, json_as_atm/2, json_as_num/2.
- Regular Types:
  json/1, json_attrs/1, json_attr/1, json_val/1, json_list/1.

Documentation on exports

REGTYPEjson/1

Usage:

A JSON object.

json(json(Attrs)) :-
    json_attrs(Attrs).

REGTYPEjson_attrs/1

Usage:

Attributes (pairs of key/value) of a JSON object.

json_attrs([]).
json_attrs([X|Xs]) :-
    json_attr(X),
    json_attrs(Xs).

REGTYPEjson_attr/1

A regular type, defined as follows:

json_attr(Id=Val) :-
    atm(Id),
    json_val(Val).

REGTYPEjson_val/1

A regular type, defined as follows:

json_val(string(X)) :-
    string(X).
json_val(X) :-
    number(X).
json_val(X) :-
    json(X).
json_val(X) :-
    json_list(X).
json_val(true).
json_val(false).
json_val(null).

REGTYPEjson_list/1

Usage:

A list of JSON elements

PREDICATEjson_to_string/2

Usage:json_to_string(Term,String)

Encode a JSON value Term as a character list.

Call and exit should be compatible with:
(json:json_val/1)json:json_val(Term)
(basic_props:string/1)String is a string (a list of character codes).
The following properties should hold at call time:
(term_typing:nonvar/1)Term is currently a term which is not a free variable.

PREDICATEstring_to_json/2

Usage:string_to_json(String,Term)

Decode a character list as a JSON value Term.

Call and exit should be compatible with:
(basic_props:string/1)String is a string (a list of character codes).
(json:json_val/1)json:json_val(Term)
The following properties should hold at call time:
(term_typing:nonvar/1)String is currently a term which is not a free variable.

PREDICATEjson_get/3