While the paper is about helping an LLM using Prolog, to give an idea for a realistic application for generating Prolog, here's the zero-shot prompt and response of a basic local Instruct LLM on a challenge to a classic 1998 AI Planning Competition "Logistics" problem re-formulated in English from PDDL, running on a very basic local 8B LLM quant'd to run on 12GB and containing even typos, but not showing the system prompt portion though. I mean, it's quite impressive and the generated state and action predicates can be run right away in the browser on eg. Quantum Prolog much like the container planning problem [1], with the main clause replaced by a generic STRIPS-like indeterministic/backtracking planning routine. Using additional training and/or in-context techniques and prompt reformulation can improve the result further.
Since the action predicates use retract/assert primitives to change state, Quantum Prolog's vardb feature [2] can also be put to good use by transforming the resulting program into an equivalent form that can be backtracked over, even in parallel, to perform combinatorical search (whereas assertz/retract in Prolog is destructive and cannot be "undone" automatically to search new states).
But as you also can see from the plan description text, a natural-language description of the problem that an LLM can comprehend only helps so much since it's highly repetitive in stating hundreds of facts about eg. current and desired package locations. This is where Prolog comes in since you can state those ground facts in clause format, or a DSL format, or a database (as in realistic applications where Prolog facts are generated or Prolog is deployed alongside a backend for integration with other services for eg. messaging in a a logistics app).
Still, the combination of an LLM (excelling at language tasks) and Prolog (for actually searching a combinatorical space spanned by clauses extracted in a natural way), just as a human reach out to a pocket calculator for certain tasks, sure is powerful and has been also explored recently in one form or another in academia eg [3] also referenced elsewhere in this thread. And this isn't even using tool calling and iterative re-prompting, etc.
[1]: https://quantumprolog.sgml.net/container-planning-demo/part1...
[2]: https://quantumprolog.sgml.net/container-planning-demo/part2...
[3]: "LLMs Can't Plan, But Can Help Planning in LLM-Modulo Frameworks" at https://arxiv.org/abs/2402.01817>
PROMPT (submitted as-is, including typos):
Write a Prolog program to solve the following logistics problem:
Packages must be transported from and to locations inside the six cities named city1, city2, city3, city4, city5, and city6) using trucks, and between those citiesusing airplanes.
Each city has two locations:
city1 has locations city11 and city12, city2 has locations city21 and city22, city3 has locations city31 and city32, city4 has locations city41 and city42, city5 has locations city51 and city52, andcity6 has locations city61 and city62.
Initially, package1 is located at city21, package2 is located at city12, package3 is located in city11, package4 is located in city11, package5 is located in city42, and package6 is located in city31.
The aim is to move package1 to city21, package2 to city62, package3 to city61, package4 to city32, package5 to city62, and package6 to city12.
In each city, at the locations city11, city21, city31, city41, city51, and city61, there's a truck to transport packages to other locations within the city. There are moreover two airplanes, named plane1 and plane2, located at the airport of city1 at location11 and at the airport of city2 at location22. The airports of the other cities have the locations location32 in city3, location42 in city4, location52 in city5, and location62 in city6.
To move packages, a sequence of actions as follows must be performed until the packages have reached their destination.
The action load_truck will place a package in a truck at a given location.
The action unload_truck will unload a package from a truck at a given location.
The action fly_airplane will fly an airplane from one airport to another.
The action unload_airplane will unload a package from an airplane at a given location.
The action load_airplane will load an airplane with a package at a given location.
RESPONSE:
% State facts
% Initial state of the packages
package(package1, city21).
package(package2, city12).
package(package3, city11).
package(package4, city11).
package(package5, city42).
package(package6, city31).
% Initial state of the trucks
truck(city11, city11).
truck(city21, city21).
truck(city31, city31).
truck(city41, city41).
truck(city51, city51).
truck(city61, city61).
% Initial state of the airplanes
airplane(plane1, city11).
airplane(plane2, city22).
% Action clauses
% load_truck :- load a package into a truck at a given location
load_truck :-
% If the given location is valid for loading a truck
location(Loc, City),
package(Pkg, Loc),
truck(T, Loc),
% Remove the package from its current location
retract(package(Pkg, Loc)),
% Add the package to the truck
assertz(package(Pkg, T)),
% Assert the new state
assertz(truck(T, Loc)).
% unload_truck :- unload a package from a truck at a given location
unload_truck :-
% If the given location is valid for unloading a truck
location(Loc, City),
package(Pkg, T),
truck(T, Loc),
% Remove the package from the truck
retract(package(Pkg, T)),
% Add the package to its destination location
assertz(package(Pkg, Loc)),
% Assert the new state
assertz(truck(T, Loc)).
% fly_airplane :- fly an airplane from one airport to another
fly_airplane :-
% If the airplane is at a valid airport
airplane(plane, Loc),
% If there is a valid destination airport
airport(Dest, DestCity),
% Remove the airplane from its current location
retract(airplane(plane, Loc)),
% Add the airplane to the destination airport
assertz(airplane(plane, Dest)).
% unload_airplane :- unload a package from an airplane at a given location
unload_airplane :-
% If the given location is valid for unloading an airplane
location(Loc, City),
package(Pkg, A),
airplane(plane, A),
% Remove the package from the airplane
retract(package(Pkg, A)),
% Add the package to its destination location
assertz(package(Pkg, Loc)),
% Assert the new state
assertz(airplane(plane, Loc)).
% load_airplane :- load a package into an airplane at a given location
load_airplane :-
% If the given location is valid for loading an airplane
location(Loc, City),
package(Pkg, Loc),
airplane(plane, A),
% Remove the package from its current location
retract(package(Pkg, Loc)),
% Add the package to the airplane
assertz(package(Pkg, A)),
% Assert the new state
assertz(airplane(plane, Loc)).
% Target state
target :-
package(package1, city22),
package(package2, city62),
package(package3, city61),
package(package4, city32),
package(package5, city62),
package(package6, city12).
% Main predicate to solve the problem
solve :- ...
% BOGUS MAIN AND HELPER CLAUSES OMITTED