如何在谓词中使用序言字典的键值？

Question

I have a simple question which I'm getting a lot of trouble finding an answer.

I'm building an api that reads json and at the moment it successfully converts the json to a dict with http_read_json_dict. The problem is that, I have no clue how to access the attributes inside the dict and use that that data in a predicate.
I tried following the swi-prolog documentation but to no avail... Do you guys know of a way?

I tried this to test read the content of the dict but I get a "key_value expected, found a dict" error. Please don't burn me at the stake:

json contains: [{"task":"learnprolog","dayofmonth":2}]

  http_read_json_dict(Request, JSONIn,[json_object(term)]),
  X = JSONIn,
  format(user_output,"task is: ~p~n",[X.task]),
  JSONOut=JSONIn.

But i was really hoping to do something like:

predicate(X):- X.dayofmonth==2,doSomething(X.task);doSomethingElse(X.task) .

Thanks a lot for the help!

Answer 1

not sure about the details, without a server setup similar to what you're using... but

?- open_codes_stream(`[{"task":"learnprolog","dayofmonth":"2"}]`,S),json_read_dict(S,[J]),close(S),write(J.dayofmonth).
2
S = <stream>(0x7f5f14304dd0),
J = _G15591{dayofmonth:"2", task:"learnprolog"}.

note the square brackets around J