lab task 3

implement main
    open core, console

class predicates
    isExists : (integer*, integer, boolean [out]).
    isSubset : (integer*, integer*, boolean [out]).

clauses
    isExists([], Element, false) :-
        !.
    isExists([X | Xs], Element, S) :-
        isExists(Xs, Element, S2),
        if X = Element then
            S = true
        else
            S = S2
        end if.

    isSubset([], Set, true) :-
        !.
    isSubset([X | Xs], Set, S) :-
        isSubset(Xs, Set, S2),
        isExists(Set, X, A),
        if A = true and S2 = true then
            S = true
        else
            S = false
        end if.
        %write(X, " ", A).

    run() :-
        init(),
        L = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13],
        L1 = [3, 4, 5, 6, 7, 8, 9, 10],
        isSubset(L, L1, A),
        write(A, "Конец. Нажмите любую клавишу "),
        _ = readchar().

end implement main

goal
    mainExe::run(main::run).