1 files changed, 117 insertions, 1 deletions
diff --git a/prolog/problems/family_relations/grandparent_2/common.py b/prolog/problems/family_relations/grandparent_2/common.py
index 1091d52..98e40fc 100644
--- a/prolog/problems/family_relations/grandparent_2/common.py
+++ b/prolog/problems/family_relations/grandparent_2/common.py
@@ -1,8 +1,14 @@
 # coding=utf-8
 
+import socket
+import prolog.engine
+import prolog.util
+from server.hints import Hint, HintSequence
+import server.problems
+
 id = 95
 group = 'family_relations'
-number = 2
+number = 30
 visible = True
 facts = 'family_relations'
 
@@ -11,3 +17,113 @@ grandparent(X, Y) :-
   parent(X, Z),
   parent(Z, Y).
 '''
+
+hint_type = {
+    'no_common_z': Hint('no_common_z'),
+    'gender_is_irrelevant': Hint('gender_is_irrelevant'),
+    'or_instead_of_and': Hint('or_instead_of_and'),
+    'x_must_be_parent': Hint('x_must_be_parent'),
+    'x_need_not_have_parent': Hint('x_need_not_have_parent'),
+    'y_must_have_parent': Hint('y_must_have_parent'),
+    'y_need_not_be_parent': Hint('y_need_not_be_parent'),
+}
+
+test_cases = [
+    # TODO
+]
+
+def test(program, solved_problems):
+    code = (program + '\n' +
+            server.problems.solutions_for_problems('prolog', solved_problems) + '\n' +
+            server.problems.load_facts('prolog', facts).facts)
+
+    engine_id = None
+    try:
+        engine_id, output = prolog.engine.create(code=code, timeout=1.0)
+        if not engine_id or 'error' in map(itemgetter(0), output):
+            # Engine creation failed, or syntax error in code.
+            return 0, len(test_cases)
+
+        n_correct = 0
+        for query, answers in test_cases:
+            # Limit inferences for each solution to curb unbounded recursion.
+            limited = 'call_with_inference_limit(({}), 100000, _)'.format(query)
+            if prolog.engine.check_answers(engine_id, query=limited, answers=answers, timeout=1.0):
+                n_correct += 1
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
+    passed = n_correct == len(test_cases)
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_cases)}}]
+    return passed, hints
+
+def hint(program, solved_problems):
+    tokens = prolog.util.tokenize(program)
+
+    code = (program + '\n' +
+            server.problems.solutions_for_problems('prolog', solved_problems) + '\n' +
+            server.problems.load_facts('prolog', facts).facts)
+
+    engine_id = None
+    try:
+        engine_id, output = prolog.engine.create(code=code, timeout=1.0)
+        if not engine_id:
+            raise Exception('Prolog engine failed to create.')
+
+        # TODO: generic hint for:
+        # TODO: parent(X, Z1), parent(Z2, Y), Z1 = Z2
+
+        # broken "link" mistake -- no common parent/child Z
+        # warning: due to speed considerations this (1024) is knowledge base dependent
+        # independent: findall(_, (parent(X, Z1), parent(Z2, Y)), L)
+        if prolog.engine.ask_truth(engine_id,
+            'findall(_, grandparent(X, Y), L), length(L, 1024)'):
+            return [{'id': 'no_common_z'}]
+
+        # gender testing is redundant
+        # this is not necessarily wrong, but worth mentioning anyway
+        targets = [prolog.util.Token('NAME', 'male'), prolog.util.Token('NAME', 'female')]
+        pos = [(t.pos, t.pos + len(t.val)) for t in tokens if t in targets]
+        if pos:
+            # TODO: resolve how highlighting info is communicated
+            return [{'id': 'gender_is_irrelevant', 'highlight': pos}]
+
+        # OR (;) instead of AND (,)
+        # this hint has to be before the next two
+        # as otherwise those two would always override it
+        # and not convey the same (amount of) help/information
+        # warning: due to speed considerations this (64) is knowledge base dependent
+        if prolog.util.Token('SEMI', ';') in tokens and prolog.engine.ask_truth(engine_id,
+            'findall(_, grandparent(X, Y), L), length(L, 64)'):
+            return [{'id': 'or_instead_of_and'}]
+
+        # X must be a parent
+        if prolog.engine.ask_truth(engine_id,
+            'grandparent(X, _), \+ parent(X, _)'):
+            return [{'id': 'x_must_be_parent'}]
+
+        # X does not necessarily need to have a parent
+        if prolog.engine.ask_one(engine_id,
+            'grandparent(X, _), \+ parent(_, X)') == 'false':
+            return [{'id': 'x_need_not_have_parent'}]
+
+        # Y must have a parent
+        if prolog.engine.ask_truth(engine_id,
+            'grandparent(_, Y), \+ parent(_, Y)'):
+            return [{'id': 'y_must_have_parent'}]
+
+        # Y does not necessarily need to be a parent
+        if prolog.engine.ask_one(engine_id,
+            'grandparent(_, Y), \+ parent(Y, _)') == 'false':
+            return [{'id': 'y_need_not_be_parent'}]
+
+    except socket.timeout as ex:
+        pass
+
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
+    return None
+