Files
mercury/tests/tabling/loopcheck_no_loop.m
2018-07-08 23:20:52 +02:00

95 lines
2.1 KiB
Mathematica

%---------------------------------------------------------------------------%
% vim: ts=4 sw=4 et ft=mercury
%---------------------------------------------------------------------------%
%
% Check that loopcheck isn't overzealous.
:- module loopcheck_no_loop.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- pragma require_feature_set([memo]).
:- import_module int.
main(!IO) :-
sum(3, Sum3),
io.write_int(Sum3, !IO),
io.write_string("\n", !IO),
sum(2, Sum2),
io.write_int(Sum2, !IO),
io.write_string("\n", !IO),
( if semisum(3, Semisum3) then
io.write_int(Semisum3, !IO),
io.write_string("\n", !IO)
else
io.write_string("semisum(3) failed\n", !IO)
),
( if semisum(2, Semisum2) then
io.write_int(Semisum2, !IO),
io.write_string("\n", !IO)
else
io.write_string("semisum(2) failed\n", !IO)
),
( if semisum(-2, SemisumN2) then
io.write_int(SemisumN2, !IO),
io.write_string("\n", !IO)
else
io.write_string("semisum(-2) failed\n", !IO)
),
( if count(3) then
io.write_string("count(3) succeeded\n", !IO)
else
io.write_string("count(3) failed\n", !IO)
),
( if count(2) then
io.write_string("count(2) succeeded\n", !IO)
else
io.write_string("count(2) failed\n", !IO)
),
( if count(-2) then
io.write_string("count(-2) succeeded\n", !IO)
else
io.write_string("count(-2) failed\n", !IO)
).
:- pred sum(int::in, int::out) is det.
:- pragma loop_check(sum/2).
sum(N, SumN) :-
( if N = 0 then
SumN = 0
else
sum(N - 1, Sum1),
SumN = Sum1 + N
).
:- pred semisum(int::in, int::out) is semidet.
:- pragma loop_check(semisum/2).
semisum(N, SumN) :-
( if N < 0 then
fail
else if N = 0 then
SumN = 0
else
semisum(N - 1, Sum1),
SumN = Sum1 + N
).
:- pred count(int::in) is semidet.
:- pragma loop_check(count/1).
count(N) :-
( if N < 0 then
fail
else if N = 0 then
true
else
count(N - 1)
).