/* ConGolog: Concurrent Delivery Robot
   Demonstrates concurrent execution of agent procedures.
   ConGolog extends Golog with concurrent composition (||),
   prioritized concurrency (>>), and interrupt handling. */

/* Primitive actions */
prim_action(pickup(X)).
prim_action(putdown(X)).
prim_action(move(Loc)).
prim_action(ring_bell).
prim_action(open_door).

/* Possibility axioms */
poss(pickup(X), S) :-
    on(X, table, S),
    \+ holding(_, S).
poss(putdown(X), S) :-
    holding(X, S).
poss(move(Loc), S) :-
    at(robot, _, S),
    Loc \= noplace.
poss(ring_bell, _S).
poss(open_door, S) :-
    door_locked(S).

/* Initial situation */
initially(on(block1, table)).
initially(on(block2, table)).
initially(at(robot, room1)).
initially(door_locked).

/* ConGolog procedures */
proc(carry(X, Dest),
    pickup(X) : move(Dest) : putdown(X)).

proc(answer_door,
    ring_bell : move(entrance) : open_door).

/* Main program: concurrent delivery and door handling */
proc(main,
    carry(block1, room2) || answer_door).

:- do(main, s0, _SF), write('Tasks completed.'), nl.