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:- module throw.
:- interface.
:- import_module io.
:- pred main(io__state, io__state).
:- mode main(di, uo) is cc_multi.

:- implementation.

:- import_module exception.
:- import_module int.

main -->
    { try(p, X) },
    io__write(X),
    io__nl,
    { try(q, Y) },
    io__write(Y),
    io__nl.

:- pred p(int::out) is cc_nondet.

p(X) :-
    a(A),
    b(A, X),
    X < 0.

:- pred a(int::out) is multi.

a(2).
a(3).

:- pred b(int::in, int::out) is multi.

b(A, B) :-
    (
        B = A * 3
    ;
        B = A * 4
    ),
    (
        B > 10
    ->
        throw("Too big")
    ;
        true
    ).

:- pred q(int::out) is semidet.

q(1) :-
    not (
        a2(A),
        not (
            b2(A, 0)
        ),
        A < 0
    ).

:- pred a2(int::out) is multi.

a2(2).
a2(3).

:- pred b2(int::in, int::out) is multi.

b2(A, B) :-
    (
        B = A * 3
    ;
        B = A * 4
    ),
    (
        B > 10
    ->
        throw("Too big")
    ;
        true
    ).