%Smart home automation
% Define the state of the light (on/off)
light_state(off).
% Define the state of the thermostat (temperature in Celsius)
thermostat_state(21).
% Define the state of the door (open/closed)
door_state(closed).
% Define the state of the lock (locked/unlocked)
lock_state(locked).
% Define the state of the motion sensor (active/inactive)
motion_sensor_state(inactive).
% Define the state of the fire sensor (alert/no_alert)
fire_sensor_state(no_alert).
% Turn on the light
turn_on_light :-
retract(light_state(off)),
asserta(light_state(on)).
% Turn off the light
turn_off_light :-
retract(light_state(on)),
asserta(light_state(off)).
% Set the thermostat temperature
set_thermostat(Temp) :-
retract(thermostat_state(_)),
asserta(thermostat_state(Temp)).
% Open the door
open_door :-
retract(door_state(closed)),
asserta(door_state(open)).
% Close the door
close_door :-
retract(door_state(open)),
asserta(door_state(closed)).
% Lock the door
lock_door :-
retract(lock_state(unlocked)),
asserta(lock_state(locked)).
% Unlock the door
unlock_door :-
retract(lock_state(locked)),
asserta(lock_state(unlocked)).
% Automatically turn on the light when motion is detected
automate_light :-
motion_sensor_state(active),
turn_on_light,
!.
% Automatically adjust the thermostat based on the current temperature
automate_thermostat :-
thermostat_state(CurrentTemp),
( CurrentTemp < 18 -> set_thermostat(18)
; CurrentTemp > 22 -> set_thermostat(22)
; true
),
!.
% Automatically unlock the door when a fire is detected
automate_door_unlock :-
fire_sensor_state(alert),
unlock_door,
!.
% Automatically lock the door when the fire alert is cleared
automate_door_lock :-
fire_sensor_state(no_alert),
lock_door,
!.
% Main loop
main :-
% Check the state of the motion sensor
motion_sensor_state(State),
( State = active -> automate_light
; true
),
% Check the state of the fire sensor
fire_sensor_state(State),
( State = alert -> automate_door_unlock
; State = no_alert -> automate_door_lock
; true
),
% Check the state of the thermostat
automate_thermostat,
% Repeat the loop
main.
% Initialize the system
init :-
retractall(_),
asserta(light_state(off)),
asserta(thermostat_state(21)),
asserta(door_state(closed)),
asserta(lock_state(locked)),
asserta(motion_sensor_state(inactive)),
asserta(fire_sensor_state(no_alert)),
main.
% Start the system
start :-
init,
main. Write, Run & Share Prolog code online using OneCompiler’s Prolog online compiler for free. It’s a simple and intuitive platform to experiment with logic programming in Prolog. OneCompiler supports standard Prolog syntax, great for learning, prototyping, and practicing logic-based problems.
Prolog (Programming in Logic) is a logic programming language associated with artificial intelligence and computational linguistics. It works through facts, rules, and queries, using a form of symbolic reasoning known as backward chaining. Prolog is declarative, meaning you describe what you want instead of how to compute it.
The following is a simple Prolog program that prints a greeting:
:- initialization(main).
main :-
write('Hello, World!').
Facts represent basic assertions about the world.
likes(alice, pizza).
likes(bob, pasta).
Rules define logical relationships using facts.
friends(X, Y) :- likes(X, Z), likes(Y, Z).
Queries are used to find information based on facts and rules.
?- likes(alice, What).
| Operator | Description |
|---|---|
:- | Rule definition |
, | Logical AND |
; | Logical OR |
= | Unification |
member(X, [X|_]).
member(X, [_|T]) :- member(X, T).
Prolog heavily relies on recursion.
factorial(0, 1).
factorial(N, F) :-
N > 0,
N1 is N - 1,
factorial(N1, F1),
F is N * F1.
This guide provides a quick reference to Prolog programming syntax and features. Start writing Prolog code using OneCompiler’s Prolog online compiler today!