From c50452d81b08d54b734f1da73b736bfbc2997215 Mon Sep 17 00:00:00 2001
From: Aleksander Sadikov <sasha@fri.uni-lj.si>
Date: Tue, 22 Sep 2015 17:57:04 +0200
Subject: New problems with hints for famrel section added.

This practically completes famrel section without some details.
---
 .../problems/family_relations/cousin_2/common.py   | 95 ++++++++++++++++++++++
 1 file changed, 95 insertions(+)

(limited to 'prolog/problems/family_relations/cousin_2/common.py')

diff --git a/prolog/problems/family_relations/cousin_2/common.py b/prolog/problems/family_relations/cousin_2/common.py
index 7cd6392..d95babd 100644
--- a/prolog/problems/family_relations/cousin_2/common.py
+++ b/prolog/problems/family_relations/cousin_2/common.py
@@ -26,3 +26,98 @@ cousin(X, Y) :-
     ;
     sister99(PX, PY) ).
 '''
+
+hint_type = {
+    'gender_is_irrelevant': Hint('gender_is_irrelevant'),
+    'precedence_fail': Hint('precedence_fail'),
+    'cousin_vs_sibling': Hint('cousin_vs_sibling'),
+    'cousin_to_oneself': Hint('cousin_to_oneself'),
+    'cousin_need_not_be_parent': Hint('cousin_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.')
+
+        # 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}]
+
+        # precedence fail (AND block vs OR block)
+        # case in point: parent(PX, X), parent(PY, Y), brother(PX, PY) ; sister(PX, PY)
+        #  or this case: parent(PX, X), parent(PY, Y), sister(PX, PY) ; brother(PX, PY)
+        # warning: knowledge base dependent
+        if prolog.util.Token('SEMI', ';') in tokens and prolog.engine.ask_truth(engine_id,
+            'findall(_, cousin(X, Y), L), (length(L, 14) ; length(L, 16))'):
+            return [{'id', 'precedence_fail'}]
+
+        # cousin should not be brother or sister
+        # common parent, probably solved via grandparent
+        if prolog.engine.ask_truth(engine_id,
+            'cousin(X, Y), (brother(X, Y) ; sister(X, Y))'):
+            return [{'id', 'cousin_vs_sibling'}]
+
+        # cousin to him/herself
+        # just common grandparent is not enough
+        if prolog.engine.ask_truth(engine_id, 'cousin(X, X)'):
+            return [{'id', 'cousin_to_oneself'}]
+
+
+        # X (or Y) does not necessarily need to be a parent
+        # cousin is a symmetrical relation, so X and Y are covered by this
+        if prolog.engine.ask_one(engine_id,
+            'cousin(X, _), \+ parent(X, _)') == 'false':
+            return [{'id': 'cousin_need_not_be_parent'}]
+
+    except socket.timeout as ex:
+        pass
+
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
+    return None
+
-- 
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