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49 lines
1.1 KiB
Mathematica
49 lines
1.1 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ts=4 sw=4 et ft=mercury
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%---------------------------------------------------------------------------%
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:- module ambiguous_method_2.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is det.
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:- implementation.
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:- import_module list.
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main(!IO) :-
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( if test(intcoll([0]), 1) then
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io.write_string("yes\n", !IO)
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else
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io.write_string("no\n", !IO)
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),
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( if e = intcoll([1]) then
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io.write_string("yes\n", !IO)
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else
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io.write_string("no\n", !IO)
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).
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:- typeclass foo(T) where [].
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:- instance foo(int) where [].
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:- typeclass coll(C, E) <= foo(E) where [
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func e = C,
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func i(C, E) = C,
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pred m(E::in, C::in) is semidet
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].
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:- type intcoll
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---> intcoll(list(int)).
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:- instance coll(intcoll, int) where [
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(e = intcoll([])),
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(i(intcoll(Ns), N) = intcoll([N | Ns])),
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m(N, intcoll([N | _])),
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m(N, intcoll([_ | Ns])) :- m(N, intcoll(Ns))
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].
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:- pred test(C::in, E::in) is semidet <= coll(C, E).
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test(C, E) :-
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m(E, i(C, E)).
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