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% vim: ts=4 sw=4 et ft=mercury
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:- module gcf.
:- interface.
:- import_module io.

:- pred main(io__state::di, io__state::uo) is cc_multi.

:- implementation.

:- import_module int.
:- import_module maybe.

main -->
    {
        a(X),
        X > 15
    ->
        R = yes(X)
    ;
        R = no
    },
    io__write(R),
    io__nl.

:- pred a(int::out) is nondet.
:- pred g(int::out) is multi.
:- pred c(int::in, int::out) is nondet.
:- pred f(int::in) is semidet.

a(X) :-
    g(Y),
    c(Y, X),
    f(X).

g(1).
g(2).
g(3).
g(4).

c(2, 10).
c(2, 11).
c(2, 12).
c(3, 20).

f(X) :-
    X > 10.