mirror of
https://github.com/Mercury-Language/mercury.git
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113 lines
2.7 KiB
Mathematica
113 lines
2.7 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ts=4 sw=4 et ft=mercury
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%---------------------------------------------------------------------------%
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:- module func_trail_test.
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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 int.
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:- pragma promise_pure(main/2).
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main(!IO) :-
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( impure trail_test ->
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io.write_string("Success\n", !IO)
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;
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io.write_string("Failure\n", !IO)
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).
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:- impure pred trail_test is failure.
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trail_test :-
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small_int(I),
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impure trail_test_message("before", I, 0),
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impure enter(I),
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small_int(J),
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impure trail_test_message("inside", I, J),
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impure leave(I),
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impure trail_test_message("after", I, J),
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fail.
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:- pred small_int(int::out) is multi.
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small_int(1).
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small_int(2).
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small_int(3).
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:- impure pred trail_test_message(string::in, int::in, int::in) is det.
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:- impure pred enter(int::in) is det.
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:- impure pred leave(int::in) is det.
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:- pragma foreign_decl("C",
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"
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#include <stdio.h>
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#include ""mercury_trail.h""
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void enter_failing(int handle, MR_untrail_reason reason);
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void leave_failing(int handle, MR_untrail_reason reason);
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").
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:- pragma foreign_proc("C",
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trail_test_message(Prefix::in, I::in, J::in),
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[will_not_call_mercury, will_not_modify_trail],
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"
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printf(\"%s: %d %d\\n\", (char *)Prefix, (int)I, (int)J);
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").
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:- pragma foreign_code("C", "
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void enter_failing(int handle, MR_untrail_reason reason) {
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switch (reason) {
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case MR_exception:
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case MR_undo:
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case MR_retry:
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/* printf(""enter_failing: exception/undo/retry\n""); */
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printf(\"=> fail back inside: %d\\n\", handle);
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break;
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default:
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printf(\"enter_failing: default\\n\");
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break;
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}
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}
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void leave_failing(int handle, MR_untrail_reason reason) {
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switch (reason) {
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case MR_exception:
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case MR_undo:
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case MR_retry:
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/* printf(""leave_failing: exception/undo/retry\n""); */
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printf(\"<= fail back outside: %d\\n\", handle);
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break;
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case MR_commit:
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case MR_solve:
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printf(\"leave_failing: commit/solve\\n\");
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break;
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default:
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printf(\"leave_failing: default\\n\");
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/* we may need to do something if reason == MR_gc */
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break;
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}
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}
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").
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:- pragma foreign_proc("C",
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enter(I::in),
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[will_not_call_mercury, may_modify_trail],
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"
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printf(\">> enter (%d)\\n\", (int) I);
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MR_trail_function(leave_failing, (void *) I);
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").
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:- pragma foreign_proc("C",
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leave(I::in),
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[will_not_call_mercury, may_modify_trail],
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"
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printf(\"<< leave (%d)\\n\", (int) I);
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MR_trail_function(enter_failing, (void *) I);
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").
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