%---------------------------------------------------------------------------%
% vim: ts=4 sw=4 et ft=mercury
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%
% This is a test of the code that extends closures.

:- module closure_extension.

:- interface.

:- import_module io.

:- pred main(io::di, io::uo) is det.

:- implementation.

:- import_module list.

main(!IO) :-
    A_1 = append_4([1]),
    call(A_1, [7], [8], [9], R_1_7_8_9),
    io.write_line(R_1_7_8_9, !IO),

    A_1_2 = ho_call_append_3(A_1, [2]),
    call(A_1_2, [8], [9], R_1_2_8_9),
    io.write_line(R_1_2_8_9, !IO),

    A_1_2_3 = ho_call_append_2(A_1_2, [3]),
    call(A_1_2_3, [9], R_1_2_3_9),
    io.write_line(R_1_2_3_9, !IO),

    A_1_2_3_4 = ho_call_append_1(A_1_2_3, [4]),
    call(A_1_2_3_4, R_1_2_3_4),
    io.write_line(R_1_2_3_4, !IO),

    A_12 = append_4([1], [2]),
    call(A_12, [8], [9], R_12_8_9),
    io.write_line(R_12_8_9, !IO),

    A_12_3 = ho_call_append_2(A_12, [3]),
    call(A_12_3, [9], R_12_3_9),
    io.write_line(R_12_3_9, !IO),

    A_12_3_4 = ho_call_append_1(A_12_3, [4]),
    call(A_12_3_4, R_12_3_4),
    io.write_line(R_12_3_4, !IO),

    A_12_34 = ho_call_append_2(A_12, [3], [4]),
    call(A_12_34, R_12_34),
    io.write_line(R_12_34, !IO),

    A_1_234 = ho_call_append_3(A_1, [2], [3], [4]),
    call(A_1_234, R_1_234),
    io.write_line(R_1_234, !IO),

    A_123 = append_4([1], [2], [3]),
    call(A_123, [9], R_123_9),
    io.write_line(R_123_9, !IO),

    A_123_4 = ho_call_append_1(A_123, [4]),
    call(A_123_4, R_123_4),
    io.write_line(R_123_4, !IO),

    A_1234 = append_4([1], [2], [3], [4]),
    call(A_1234, R_1234),
    io.write_line(R_1234, !IO),

    ho_call_append_3(A_1, [7], [8], [9], H_1_7_8_9),
    io.write_line(H_1_7_8_9, !IO),

    ho_call_append_2(A_1_2, [8], [9], H_1_2_8_9),
    io.write_line(H_1_2_8_9, !IO),

    ho_call_append_1(A_1_2_3, [9], H_1_2_3_9),
    io.write_line(H_1_2_3_9, !IO),

    ho_call_append_0(A_1_2_3_4, H_1_2_3_4),
    io.write_line(H_1_2_3_4, !IO),

    ho_call_append_2(A_12, [8], [9], H_12_8_9),
    io.write_line(H_12_8_9, !IO),

    ho_call_append_1(A_12_3, [9], H_12_3_9),
    io.write_line(H_12_3_9, !IO),

    ho_call_append_0(A_12_3_4, H_12_3_4),
    io.write_line(H_12_3_4, !IO),

    ho_call_append_0(A_12_34, H_12_34),
    io.write_line(H_12_34, !IO),

    ho_call_append_0(A_1_234, H_1_234),
    io.write_line(H_1_234, !IO),

    ho_call_append_1(A_123, [9], H_123_9),
    io.write_line(H_123_9, !IO),

    ho_call_append_0(A_123_4, H_123_4),
    io.write_line(H_123_4, !IO),

    ho_call_append_0(A_1234, H_1234),
    io.write_line(H_1234, !IO).

:- pred ho_call_append_0(pred(list(T)), list(T)).
:- mode ho_call_append_0(pred(out) is det, out) is det.

ho_call_append_0(P0, R) :-
    P0(R).

:- pred ho_call_append_1(pred(list(T), list(T)), list(T), list(T)).
:- mode ho_call_append_1(pred(in, out) is det, in, out) is det.

ho_call_append_1(P0, Z, R) :-
    P0(Z, R).

:- pred ho_call_append_2(pred(list(T), list(T), list(T)),
    list(T), list(T), list(T)).
:- mode ho_call_append_2(pred(in, in, out) is det, in, in, out) is det.

ho_call_append_2(P0, Y, Z, R) :-
    P0(Y, Z, R).

:- pred ho_call_append_3(pred(list(T), list(T), list(T), list(T)),
    list(T), list(T), list(T), list(T)).
:- mode ho_call_append_3(pred(in, in, in, out) is det, in, in, in, out) is det.

ho_call_append_3(P0, X, Y, Z, R) :-
    P0(X, Y, Z, R).

:- pred append_4(list(T)::in, list(T)::in, list(T)::in, list(T)::in,
    list(T)::out) is det.

append_4(A, B, C, D, ABCD) :-
    append(A, B, AB),
    append(AB, C, ABC),
    append(ABC, D, ABCD).