def test_assert_retract():
e = get_engine("g(b, b).")
assert_true("g(B, B).", e)
assert_true("assert(g(c, d)).", e)
assert_true("assert(g(a, b)).", e)
assert_true("assert(g(a, b)).", e) # assert the same rule multiple times
assert_true("g(B, B).", e)
assert_true("g(a, b).", e)
assert_true("g(c, d).", e)
assert_true("retract(g(B, B)).", e)
assert_false("g(B, B).", e)
assert_true("retract(g(a, b)).", e)
assert_true("g(a, b).", e)
assert_true("retract(g(a, b)).", e)
assert_false("retract(g(a, b)).", e)
assert_false("g(a, b).", e)
assert_true("g(c, d).", e)
e = get_engine("""
g(b, b).
f(X) :- g(X, b).
f(a).
""")
assert_true("f(b).", e)
assert_true("f(a).", e)
assert_true("retract(f(X) :- g(X, Y)), Y == b.", e)
assert_false("f(b).", e)
assert_true("f(a).", e)
prolog_raises("permission_error(X, Y, Z)", "retract(atom(X))")
def test_assert_retract():
e = get_engine("g(b, b).")
assert_true("g(B, B).", e)
assert_true("assert(g(c, d)).", e)
assert_true("assert(g(a, b)).", e)
assert_true("assert(g(a, b)).", e) # assert the same rule multiple times
assert_true("g(B, B).", e)
assert_true("g(a, b).", e)
assert_true("g(c, d).", e)
assert_true("retract(g(B, B)).", e)
assert_false("g(B, B).", e)
assert_true("retract(g(a, b)).", e)
assert_true("g(a, b).", e)
assert_true("retract(g(a, b)).", e)
assert_false("retract(g(a, b)).", e)
assert_false("g(a, b).", e)
assert_true("g(c, d).", e)
e = get_engine("""
g(b, b).
f(X) :- g(X, b).
f(a).
""")
assert_true("f(b).", e)
assert_true("f(a).", e)
assert_true("retract(f(X) :- g(X, Y)), Y == b.", e)
assert_false("f(b).", e)
assert_true("f(a).", e)
prolog_raises("permission_error(X, Y, Z)", "retract(atom(X))")
def test_exception():
e = get_engine("""
f(0).
f(X) :- X>0, X0 is X - 1, throw(continue(X0)).
g(X) :- catch(f(X), continue(X0), g(X0)).""")
query = Callable.build("g", [Number(100)])
e.run_query(query, e.modulewrapper.user_module, CheckContinuation(e))
def test_cut():
e = get_engine("""
f(0).
f(X) :- X>0, X0 is X - 1, !, f(X0).
f(_).""")
query = Callable.build("f", [Number(100)])
e.run_query(query, e.modulewrapper.user_module, CheckContinuation(e))
def test_serialize():
e = get_engine("""
serialise :- serialise([65, 66, 76, 69, 32, 87, 65, 83, 32, 32, 73, 32, 83, 65, 87, 32, 69, 76, 66, 65],_).
serialise(L,R) :-
pairlists(L,R,A),
arrange(A,T),
numbered(T,1,_).
pairlists([X|L],[Y|R],[pair(X,Y)|A]) :- pairlists(L,R,A).
pairlists([],[],[]).
arrange([X|L],tree(T1,X,T2)) :-
split(L,X,L1,L2),
arrange(L1,T1),
arrange(L2,T2).
arrange([],void).
split([X|L],X,L1,L2) :- !, split(L,X,L1,L2).
split([X|L],Y,[X|L1],L2) :- before(X,Y), !, split(L,Y,L1,L2).
split([X|L],Y,L1,[X|L2]) :- before(Y,X), !, split(L,Y,L1,L2).
split([],_,[],[]).
before(pair(X1,_),pair(X2,_)) :- X1 < X2.
numbered(tree(T1,pair(_,N1),T2),N0,N) :-
numbered(T1,N0,N1),
N2 is N1+1,
numbered(T2,N2,N).
numbered(void,N,N).
""")
query = Callable.build("serialise")
e.run_query(query, e.modulewrapper.user_module, CheckContinuation(e))
def test_recurse_with_if():
e = get_engine("""
equal(0, 0). equal(X, X).
f(X) :- equal(X, 0) -> true ; Y is X - 1, f(Y).
""")
query = Callable.build("f", [Number(100)])
e.run_query(query, e.modulewrapper.user_module, CheckContinuation(e))
def test_traceback_print():
e = get_engine("""
h(y).
g(a).
g(_) :- throw(foo).
f(X, Y) :-
g(X),
h(Y).
:- assert((h :- g(b), true)).
""")
error = get_uncaught_error("f(1, Y).", e)
s = error.format_traceback(e)
assert s == """\
Traceback (most recent call last):
File "<unknown>" lines 5-7 in user:f/2
f(X, Y) :-
g(X),
h(Y).
File "<unknown>" line 4 in user:g/1
g(_) :- throw(foo).
Unhandled exception: foo"""
error = get_uncaught_error("h.", e)
s = error.format_traceback(e)
assert s == """\
def test_copy_term_3():
assert_true("copy_term(a, a, []).")
assert_true("copy_term(X, Y, []), X \== Y.")
assert_false("put_attr(X, foor, bar), copy_term(X, Y, _), X == Y.")
assert_false("put_attr(X, foo, bar), copy_term(X, Y, Z), attvar(Y).")
assert_true("put_attr(X, foo, bar), copy_term(X, Y, Z), \+ attvar(Y).")
assert_true(
"put_attr(X, foo, bar), copy_term(X, Y, Z), Z == [put_attr(Y, foo, bar)], X \== Y."
)
assert_true(
"put_attr(X, foo, bar), put_attr(X, blar, blupp), copy_term(X, Y, Z), Z == [put_attr(Y, foo, bar), put_attr(Y, blar, blupp)], X \== Y."
)
e = get_engine("",
m="""
:- module(m, []).
attr_unify_hook(_, _).
""")
assert_true("put_attr(X, m, 1), X = a, copy_term(X, a, Z), Z == [].", e)
assert_true(
"put_attr(X, a, 1), put_attr(Y, b, 2), copy_term(f(X,Y), f(A, B), [put_attr(A, a, 1), put_attr(B, b, 2)]), Z \== f(X, Y)."
)
assert_true("put_attr(X, a, Y), copy_term(X, A, [put_attr(A, a, Y)]).")
assert_true("(put_attr(X, m, 1), fail; true), copy_term(X, A, []).")
assert_true(
"copy_term(X, A, []), put_attr(X, m, 1), copy_term(X, A, [put_attr(A, m, 1)])."
)
def test_term_attvars():
e = get_engine("",
m="""
:- module(m, []).
attr_unify_hook(_, _).
""")
assert_true("term_attvars(a, []).")
assert_true("term_attvars([], []).")
assert_false("term_attvars([], 1).")
assert_true("put_attr(X, m, 1), term_attvars(X, [X]).")
assert_true("term_attvars(X,Y), Y == [].")
assert_true("put_attr(X, m, 1), term_attvars(f(g(h(X)), X), [X]).")
assert_true(
"put_attr(X, m, 1), put_attr(Y, m, 2), term_attvars(f(X, Y), [X, Y]).")
assert_false(
"put_attr(X, m, 1), put_attr(Y, m, 2), X = Y, term_attvars(f(X, Y), [X, Y]).",
e)
assert_true(
"put_attr(X, m, 1), put_attr(Y, m, 2), X = Y, term_attvars(f(X, Y), [X]).",
e)
assert_true(
"put_attr(X, m, 1), put_attr(Y, m, 2), X = Y, term_attvars(f(X, Y), [Y]).",
e)
assert_true("put_attr(X, m, 1), term_attvars(f(A, X, B, X), [X]).")
assert_true("put_attr(X, m, 1), Y = X, term_attvars(f(X, Y), [Y]).")
assert_true("put_attr(X, m, 1), Y = X, term_attvars(f(X, Y), [X]).")
assert_true("term_attvars(X, []), put_attr(X, m, 1).")
assert_true(
"put_attr(X, m , 1), term_attvars(X, [X]), del_attr(X, m), term_attvars(X, [])."
)
assert_true("put_attr(X, m, Y), term_variables(X, L), L == [X].")
def test_run_hook_once():
e = get_engine("",
m="""
:- module(m, []).
attr_unify_hook(Attr, Value) :-
assert(user:f(Value)).
""")
assert_true("put_attr(X, m, 1), X = a, X = a.", e)
assert_true("findall(Y, f(Y), [a]).", e)
assert_true("abolish(f/1).", e) # clear the database
assert_true(
"""
put_attr(X, m, 1), put_attr(Y, m, 2),
X = a, (X = a, fail; Y = b),
findall(A, f(A), [a, b]).
""", e)
assert_true("abolish(f/1).", e)
assert_true(
"""
put_attr(X, m, 1), put_attr(Y, m, 2),
(f(X, b) = f(a, a); Y = b),
findall(A, f(A), [b]).
""", e)
assert_true("abolish(f/1).", e)
assert_true(
"""
put_attr(X, m, 1), (X = a, fail; true),
findall(Z, f(Z), [a]).
""", e)
def test_traceback_print():
e = get_engine("""
h(y).
g(a).
g(_) :- throw(foo).
f(X, Y) :-
g(X),
h(Y).
:- assert((h :- g(b), true)).
""")
error = get_uncaught_error("f(1, Y).", e)
s = error.format_traceback(e)
assert s == """\
Traceback (most recent call last):
File "<unknown>" lines 5-7 in user:f/2
f(X, Y) :-
g(X),
h(Y).
File "<unknown>" line 4 in user:g/1
g(_) :- throw(foo).
Unhandled exception: foo"""
error = get_uncaught_error("h.", e)
s = error.format_traceback(e)
assert s == """\
def test_hook_not_defined():
e = get_engine("",
m = """
:- module(m2, []).
""")
prolog_raises("existence_error(A, B)", "put_attr(X, bla, blub), X = 1")
prolog_raises("existence_error(A, B)", "put_attr(X, m, blub), X = 1", e)
def test_integration_efficient_bools():
e = get_engine("",
swi_bool_pred = """
:- module(swi_bool_pred, [negate/2]).
negate(X, Y) :-
( nonvar(X) -> negate3(X, Y)
; nonvar(Y) -> negate3(Y, X)
; get_attr(X, swi_bool_pred, OtherX) -> Y = OtherX, X \== Y, put_attr(Y, swi_bool_pred, X)
; get_attr(Y, swi_bool_pred, OtherY) -> X = OtherY, X \== Y, put_attr(X, swi_bool_pred, Y)
; X \== Y, put_attr(Y, swi_bool_pred, X), put_attr(X, swi_bool_pred, Y)
).
negate3(pred_true, pred_false).
negate3(pred_false, pred_true).
attr_unify_hook(Other, Value) :-
(var(Value) -> (get_attr(Value, swi_bool_pred, Other2)
-> Other = Other2, Value \== Other
; put_attr(Value, swi_bool_pred, Other)
)
; negate3(Value, Other)).
""")
assert_true("swi_bool_pred:negate(X,Y), swi_bool_pred:negate(Y,Z), X==Z, Z=pred_true, X==pred_true, Y==pred_false.", e)
assert_true("swi_bool_pred:negate(X,Y), swi_bool_pred:negate(Y,Z), X==Z, Z=pred_true, X==pred_true, Y==pred_false.", e)
assert_true("swi_bool_pred:negate(X,Y), swi_bool_pred:negate(X2,Y2), X=X2, Y==Y2, Y=pred_false, X2==pred_true.", e)
assert_true("swi_bool_pred:negate(X,Y), swi_bool_pred:negate(X,Z), Y==Z, Z=pred_true, X==pred_false.", e)
assert_true("swi_bool_pred:negate(X,Y), swi_bool_pred:negate(Y,Z), \+ swi_bool_pred:negate(Z,X).", e)
assert_true("swi_bool_pred:negate(X,Y), swi_bool_pred:negate(Y,Z), swi_bool_pred:negate(Z,X2), \+ X2=X.", e)
assert_true("swi_bool_pred:negate(X,Y), swi_bool_pred:negate(Y,Z), X2=X, \+ swi_bool_pred:negate(Z,X2).", e)
assert_false("swi_bool_pred:negate(X,X).", e)
def test_cut():
e = get_engine("""
f(0).
f(X) :- Y is X - 1, !, f(Y).
f(X) :- Y is X - 2, !, f(Y).
""")
assert_true("f(20).", e)
def test_trivial():
e = get_engine("""
f(a).
""")
t, vars = get_query_and_vars("f(X).")
e.run_query_in_current(t)
assert vars['X'].dereference(None).name()== "a"
def test_trivial():
e = get_engine("""
f(a).
""")
t, vars = get_query_and_vars("f(X).")
e.run_query_in_current(t)
assert vars['X'].dereference(None).name() == "a"
def test_run_hook_once():
e = get_engine("",
m = """
:- module(m, []).
attr_unify_hook(Attr, Value) :-
assert(user:f(Value)).
""")
assert_true("put_attr(X, m, 1), X = a, X = a.", e)
assert_true("findall(Y, f(Y), [a]).", e)
assert_true("abolish(f/1).", e) # clear the database
assert_true("""
put_attr(X, m, 1), put_attr(Y, m, 2),
X = a, (X = a, fail; Y = b),
findall(A, f(A), [a, b]).
""", e)
assert_true("abolish(f/1).", e)
assert_true("""
put_attr(X, m, 1), put_attr(Y, m, 2),
(f(X, b) = f(a, a); Y = b),
findall(A, f(A), [b]).
""", e)
assert_true("abolish(f/1).", e)
assert_true("""
put_attr(X, m, 1), (X = a, fail; true),
findall(Z, f(Z), [a]).
""", e)
def test_or_and_call_with_cut():
e = get_engine("""
f :- (!, fail); true.
g :- (call(!), fail); true.
""")
assert_false("f.", e)
assert_true("g.", e)
def test_block():
e = get_engine("""
:- block f('?', '-', '?'), f('-', '-', '?').
:- block g('?').
:- block h('-', '-', '-', '?'), h('-', '-', '?', '?'), h('-', '?', '?', '?').
f(A, B, C) :-
C = 10.
g(_) :-
assert(gg(1)).
h(A, B, C, D) :-
D is A + B + C.
""", load_system=True)
assert_false("f(X, Y, Z), Z == 10.", e)
assert_false("f(a, X, Z), Z == 10.", e)
assert_true("f(a, b, Z), Z == 10.", e)
assert_true("f(a, X, Z), \+ Z == 10, X = 5, Z == 10.", e)
assert_true("f(A, B, Z), \+ Z == 10, A = a, \+ Z == 10, B = b, Z == 10.", e)
assert_true("f(a, X, Z), (X = 1, fail; true), var(Z).", e)
prolog_raises("existence_error(_, _)", "g(5), gg(1)", e)
prolog_raises("existence_error(_, _)", "g(X), gg(1)", e)
assert_true("h(A, B, C, D), var(D), C = 5, var(D), B = 5, var(D), A = 5, D == 15.", e)
prolog_raises("instantiation_error", "h(5, B, C, D)", e)
prolog_raises("instantiation_error", "h(5, 1, C, D)", e)
assert_true("h(1, 2, 3, 6).", e)
assert_true("h(A, B, C, D), var(D), B = 5, var(D), C = 5, var(D), A = 5, D == 15.", e)
def test_or_and_call_with_cut():
e = get_engine("""
f :- (!, fail); true.
g :- (call(!), fail); true.
""")
assert_false("f.", e)
assert_true("g.", e)
def test_or_with_cut():
e = get_engine("""
f(X) :- ((X = 1, !); X = 2), X = 2.
g(X) :- ((X = 1, !); X = 2), X = 1.
""")
assert_false("f(X).", e)
assert_true("g(X).", e)
def test_or_with_cut():
e = get_engine("""
f(X) :- ((X = 1, !); X = 2), X = 2.
g(X) :- ((X = 1, !); X = 2), X = 1.
""")
assert_false("f(X).", e)
assert_true("g(X).", e)
def test_cut():
e = get_engine("""
f(0).
f(X) :- Y is X - 1, !, f(Y).
f(X) :- Y is X - 2, !, f(Y).
""")
assert_true("f(20).", e)
def test_retract_logical_update_view():
e = get_engine("""
p :- retract(p :- true), fail.
p :- true.
""")
assert_true("p.", e)
assert_false("p.", e)
def test_retract_logical_update_view():
e = get_engine("""
p :- retract(p :- true), fail.
p :- true.
""")
assert_true("p.", e)
assert_false("p.", e)
def test_numeral():
e = get_engine("""
num(0).
num(succ(X)) :- num(X).
add(X, 0, X).
add(X, succ(Y), Z) :- add(succ(X), Y, Z).
mul(X, 0, 0).
mul(X, succ(0), X).
mul(X, succ(Y), Z) :- mul(X, Y, A), add(A, X, Z).
factorial(0, succ(0)).
factorial(succ(X), Y) :- factorial(X, Z), mul(Z, succ(X), Y).
""")
def nstr(n):
if n == 0:
return "0"
return "succ(%s)" % nstr(n - 1)
e.run_query_in_current(parse_query_term("num(0)."))
e.run_query_in_current(parse_query_term("num(succ(0))."))
t, vars = get_query_and_vars("num(X).")
e.run_query_in_current(t)
assert vars['X'].dereference(None).num == 0
e.run_query_in_current(parse_query_term("add(0, 0, 0)."))
py.test.raises(UnificationFailed, e.run_query_in_current, parse_query_term("""
add(0, 0, succ(0))."""))
e.run_query_in_current(parse_query_term("add(succ(0), succ(0), succ(succ(0)))."))
e.run_query_in_current(parse_query_term("mul(succ(0), 0, 0)."))
e.run_query_in_current(parse_query_term("mul(succ(succ(0)), succ(0), succ(succ(0)))."))
e.run_query_in_current(parse_query_term("mul(succ(succ(0)), succ(succ(0)), succ(succ(succ(succ(0)))))."))
e.run_query_in_current(parse_query_term("factorial(0, succ(0))."))
e.run_query_in_current(parse_query_term("factorial(succ(0), succ(0))."))
e.run_query_in_current(parse_query_term("factorial(%s, %s)." % (nstr(5), nstr(120))))
def test_cut_with_throw():
e = get_engine("""
raise_if_var(X) :-
var(X), !, throw(unbound).
raise_if_var(X) :- X = a.
c(X, Y) :- catch((raise_if_var(X), Y = b), E, Y = a).
""")
assert_true("c(_, Y), Y == a.", e)
def test_fail():
e = get_engine("""
g(a).
f(X) :- g(X), fail.
f(a).
""")
heaps = collect_all(e, "f(X).")
assert len(heaps) == 1
def test_repeat():
assert_true("repeat, true.")
e = Engine()
assert_false("repeat, !, fail.")
# hard to test repeat differently
e = get_engine('f :- repeat, !, fail.')
assert_false('f.', e)
assert_true('f; true.', e)
def test_fail():
e = get_engine("""
g(a).
f(X) :- g(X), fail.
f(a).
""")
heaps = collect_all(e, "f(X).")
assert len(heaps) == 1
def test_repeat():
assert_true("repeat, true.")
e = Engine()
assert_false("repeat, !, fail.")
# hard to test repeat differently
e = get_engine('f :- repeat, !, fail.')
assert_false('f.', e)
assert_true('f; true.', e)
def test_cut_with_throw():
e = get_engine("""
raise_if_var(X) :-
var(X), !, throw(unbound).
raise_if_var(X) :- X = a.
c(X, Y) :- catch((raise_if_var(X), Y = b), E, Y = a).
""")
assert_true("c(_, Y), Y == a.", e)
def test_runstring():
e = get_engine("foo(a, c).")
e.runstring("""
:- op(450, xfy, foo).
a foo b.
b foo X :- a foo X.
""")
assert_true("foo(a, b).", e)
def test_runstring():
e = get_engine("foo(a, c).")
e.runstring("""
:- op(450, xfy, foo).
a foo b.
b foo X :- a foo X.
""")
assert_true("foo(a, b).", e)
def test_two_cuts():
e = get_engine("""
f(>, X) :- X > 0, !.
f(=, X) :- X = 0, !.
f(<, _).
""")
assert_true("f(X, 1), X = '>'.", e)
assert_true("f(X, 0), X = '='.", e)
assert_true("f(X, -1), X = '<'.", e)
def test_call_cut():
e = get_engine("""
f(X) :- call(X).
f(!).
""")
heaps = collect_all(e, "f(!).")
assert len(heaps) == 2
assert_true("call(((X = a; X = b), !, X = b)); X = c.")
assert_false("(((X = a; X = b), !, X = b)); X = c.")
def test_and_long():
e = get_engine("""
f(x). f(y). f(z).
g(a). g(b). g(c).
h(d). h(e). h(f).
f(X, Y, Z) :- f(X), g(Y), h(Z).
""")
heaps = collect_all(e, "f(X, Y, Z).")
assert len(heaps) == 27
def test_or():
assert_false("fail;fail.")
e = get_engine("""
f(X, Y) :-
( fail
; X \== Y
).
""")
assert_false("f(X,X).", e)
def test_and_long():
e = get_engine("""
f(x). f(y). f(z).
g(a). g(b). g(c).
h(d). h(e). h(f).
f(X, Y, Z) :- f(X), g(Y), h(Z).
""")
heaps = collect_all(e, "f(X, Y, Z).")
assert len(heaps) == 27
def test_assert_logical_update_view():
e = get_engine("""
g(a).
g(c) :- assertz(g(d)).
g(b).
""")
heaps = collect_all(e, "g(X).")
assert len(heaps) == 3
e = get_engine("""
p :- assertz(p), fail.
p :- fail.
""")
assert_false("p.", e)
e = get_engine("""
q :- fail.
q :- assertz(q), fail.
""")
assert_false("q.", e)
def test_assert_logical_update_view():
e = get_engine("""
g(a).
g(c) :- assertz(g(d)).
g(b).
""")
heaps = collect_all(e, "g(X).")
assert len(heaps) == 3
e = get_engine("""
p :- assertz(p), fail.
p :- fail.
""")
assert_false("p.", e)
e = get_engine("""
q :- fail.
q :- assertz(q), fail.
""")
assert_false("q.", e)
def test_or():
assert_false("fail;fail.")
e = get_engine("""
f(X, Y) :-
( fail
; X \== Y
).
""")
assert_false("f(X,X).", e)
def test_multiple_hooks_one_not_defined():
e = get_engine("",
m = """
:- module(m, []).
attr_unify_hook(_, _).
""")
prolog_raises("existence_error(_, _)", "put_attr(X, m, 1), put_attr(X, n, 2), X = a", e)
prolog_raises("existence_error(_, _)", "put_attr(X, m, 1), put_attr(Y, n, 2), X = a, Y = X", e)
prolog_raises("existence_error(_, _)", "put_attr(X, m, 1), put_attr(Y, n, 2), X = a, X = Y", e)
def test_findall():
assert_true("findall(X, (X = a; X = b; X = c), L), L == [a, b, c].")
assert_true("findall(X + Y, (X = 1; X = 2), [1+A, 2+B]), A \== B.")
e = get_engine("""
app([], X, X).
app([H | T1], T2, [H | T3]) :-
app(T1, T2, T3).
""")
assert_true("findall(X+Y, app(X, Y, [1, 2, 3]), L), L == [[]+[1, 2, 3], [1]+[2, 3], [1, 2]+[3], [1, 2, 3]+[]].", e)
def test_two_cuts():
e = get_engine("""
f(>, X) :- X > 0, !.
f(=, X) :- X = 0, !.
f(<, _).
""")
assert_true("f(X, 1), X = '>'.", e)
assert_true("f(X, 0), X = '='.", e)
assert_true("f(X, -1), X = '<'.", e)
def test_call_cut():
e = get_engine("""
f(X) :- call(X).
f(!).
""")
heaps = collect_all(e, "f(!).")
assert len(heaps) == 2
assert_true("call(((X = a; X = b), !, X = b)); X = c.")
assert_false("(((X = a; X = b), !, X = b)); X = c.")
def test_4_queens():
e = get_engine("""
queens(Vars) :-
Vars = [_A, _B, _C, _D],
safe(Vars),
perm([1,2,3,4], Vars).
safe([]).
safe([H|T]) :-
safe(T),
attack(H, 1, T).
attack(_, _, []).
attack(X, N, [H|T]) :-
when((nonvar(X), nonvar(H)), (not(X is H + N; X is H - N))),
N1 is N + 1,
attack(X, N1, T).
perm([1,2,3,4], [1,2,3,4]).
perm([1,2,3,4], [1,2,4,3]).
perm([1,2,3,4], [1,3,2,4]).
perm([1,2,3,4], [1,3,4,2]).
perm([1,2,3,4], [1,4,2,3]).
perm([1,2,3,4], [1,4,3,2]).
perm([1,2,3,4], [2,1,3,4]).
perm([1,2,3,4], [2,1,4,3]).
perm([1,2,3,4], [2,3,1,4]).
perm([1,2,3,4], [2,3,4,1]).
perm([1,2,3,4], [2,4,1,3]).
perm([1,2,3,4], [2,4,2,1]).
perm([1,2,3,4], [3,1,2,4]).
perm([1,2,3,4], [3,1,4,2]).
perm([1,2,3,4], [3,2,1,4]).
perm([1,2,3,4], [3,2,4,1]).
perm([1,2,3,4], [3,4,1,2]).
perm([1,2,3,4], [3,4,2,1]).
perm([1,2,3,4], [4,1,3,2]).
perm([1,2,3,4], [4,1,2,3]).
perm([1,2,3,4], [4,2,1,3]).
perm([1,2,3,4], [4,2,3,1]).
perm([1,2,3,4], [4,3,1,2]).
perm([1,2,3,4], [4,3,2,1]).
""",
load_system=True)
assert_true("queens([2, 4, 1, 3]).", e)
assert_true("queens([3, 1, 4, 2]).", e)
assert_false("queens([4, 2, 1, 3]).", e)
assert_true("queens(X), X == [2, 4, 1, 3].", e)
assert_true("queens(X), X == [3, 1, 4, 2].", e)
assert_false("queens(X), X == [4, 2, 1, 3].", e)
assert_true("findall(X, queens(X), L), L == [[2, 4, 1, 3], [3, 1, 4, 2]].",
e)
def test_assert_retract_colon():
e = get_engine("""
:(1, 2, 3).
:(a).
""")
assert_true(":(1, 2, 3), :(a).", e)
assert_true("assert(:(a, b, c, d)).", e)
assert_true(":(a, b, c, d).", e)
assert_true("retract(:(a, b, c, d)).", e)
prolog_raises("existence_error(_, _)", ":(a, b, c, d)", e)
def test_abolish_colon():
e = get_engine("""
:(a).
:(1, 2, 3).
""")
assert_true("abolish(:/1).", e)
prolog_raises("existence_error(_, _)", ":(a)", e)
assert_true(":(1, 2, 3).", e)
assert_true("abolish(:/3).", e)
prolog_raises("existence_error(_, _)", ":(1, 2, 3)", e)
def test_cut2():
e = get_engine("""
g(a).
g(b).
h(a, x).
h(a, y).
f(X, Y) :- g(X), !, !, !, !, !, h(X, Y).
""")
heaps = collect_all(e, "f(X, Y).")
assert len(heaps) == 2
def test_call():
e = get_engine("g(b, b).")
assert_true("call(g(X, X)).", e)
assert_true("X =.. [g, b, b], call(X).", e)
e = get_engine("""
g(X) :- call(f(X)).
g(a).
g(b).
f(X) :- !, h(X).
f(a).
f(b).
h(X) :- fail.
withcut(X) :- call(!), fail.
withcut(a).
""")
heaps = collect_all(e, "g(X).")
assert len(heaps) == 2
assert_true("withcut(a).", e)
assert_true("call((!, true)).")
def test_cut2():
e = get_engine("""
g(a).
g(b).
h(a, x).
h(a, y).
f(X, Y) :- g(X), !, !, !, !, !, h(X, Y).
""")
heaps = collect_all(e, "f(X, Y).")
assert len(heaps) == 2
def test_backtrack_to_same_choice_point():
e = get_engine("""
a(a).
b(b).
start(Z) :- Z = X, f(X, b), X == b, Z == b.
f(X, Y) :- a(Y).
f(X, Y) :- X = a, a(Y).
f(X, Y) :- X = b, b(Y).
""")
assert_true("start(Z).", e)
def test_indexing2():
e = get_engine("""
mother(o, j).
mother(o, m).
mother(o, b).
sibling(X, Y) :- mother(Z, X), mother(Z, Y).
""")
heaps = collect_all(e, "sibling(m, X).")
assert len(heaps) == 3
def test_call():
e = get_engine("g(b, b).")
assert_true("call(g(X, X)).", e)
assert_true("X =.. [g, b, b], call(X).", e)
e = get_engine("""
g(X) :- call(f(X)).
g(a).
g(b).
f(X) :- !, h(X).
f(a).
f(b).
h(X) :- fail.
withcut(X) :- call(!), fail.
withcut(a).
""")
heaps = collect_all(e, "g(X).")
assert len(heaps) == 2
assert_true("withcut(a).", e)
assert_true("call((!, true)).")
def test_abolish_colon():
e = get_engine("""
:(a).
:(1, 2, 3).
""")
assert_true("abolish(:/1).", e)
prolog_raises("existence_error(_, _)", ":(a)", e)
assert_true(":(1, 2, 3).", e)
assert_true("abolish(:/3).", e)
prolog_raises("existence_error(_, _)", ":(1, 2, 3)", e)