1 files changed, 99 insertions, 5 deletions

diff --git a/prolog/problems/sorting/pivoting_4/common.py b/prolog/problems/sorting/pivoting_4/common.py
index 17cf270..aeb430f 100644
--- a/prolog/problems/sorting/pivoting_4/common.py
+++ b/prolog/problems/sorting/pivoting_4/common.py
@@ -1,11 +1,11 @@
-# coding=utf-8
-
 from operator import itemgetter
+import socket
+
 import prolog.engine
-import server.problems
+from server.hints import Hint, HintPopup
 
 id = 124
-number = 31
+number = 50
 visible = False
 facts = None
 
@@ -19,6 +19,22 @@ pivoting(P, [H|T], S, [H|G]) :-
   pivoting(P, T, S, G).
 '''
 
+hint_type = {
+    'eq_instead_of_equ_markup': HintPopup('eq_instead_of_equ_markup'),
+    'eq_instead_of_equ': Hint('eq_instead_of_equ'),
+    'predicate_always_false': Hint('predicate_always_false'),
+    'base_case': Hint('base_case'),
+    'recursive_case': Hint('recursive_case'),
+    'timeout': Hint('timeout'),
+    '>_and_<_mixed_up': Hint('>_and_<_mixed_up'),
+    'duplicates_not_considered': Hint('duplicates_not_considered'),
+    'all_elements_in_either_S_or_G': Hint('all_elements_in_either_S_or_G'),
+    'arbitrary_solution': Hint('arbitrary_solution'),
+    'unprotected_branch': Hint('unprotected_branch'),
+    'forcing_result_onto_recursion': Hint('forcing_result_onto_recursion'),
+    'no_recursion_in_one_branch': Hint('no_recursion_in_one_branch'),
+}
+
 test_cases = [
     ('pivoting(5, [], A, B)',
         [{'A': '[]', 'B': '[]'}]),
@@ -50,5 +66,83 @@ def test(code, aux_code):
     return n_correct, len(test_cases), hints
 
 def hint(code, aux_code):
-    # TODO
+    tokens = prolog.util.tokenize(code)
+
+    try:
+        engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0)
+
+        # strict equality testing instead of simple matching
+        # this is usually (but not necessarily) wrong
+        targets = [prolog.util.Token('EQ', '==')]
+        marks = [(t.pos, t.pos + len(t.val)) for t in tokens if t in targets]
+        if marks:
+            return [{'id': 'eq_instead_of_equ_markup', 'start': m[0], 'end': m[1]} for m in marks] + \
+                   [{'id': 'eq_instead_of_equ'}]
+
+        if prolog.engine.ask_truthTO(engine_id, '''\
+                pivoting(4, [3, 5, 9, 6, 3, 7, 2], A, B),
+                msort(A, [5, 6, 7, 9]),
+                msort(B, [2, 3, 3])'''):
+            return [{'id': '>_and_<_mixed_up'}]
+
+        if prolog.engine.ask_truthTO(engine_id, '''\
+                pivoting(4, [2, 1, 3], [2, 1, 3], []),
+                pivoting(4, [3, 5, 9, 5, 2], [3 | yowza], [5 | brix])
+                ;
+                pivoting(4, [6, 5, 7], [], [6, 5, 7]),
+                pivoting(4, [3, 5, 9, 5, 2], [3 | yowza], [5 | brix])'''):
+            return [{'id': 'no_recursion_in_one_branch'}]
+
+        if prolog.engine.ask_truthTO(engine_id, '''\
+                pivoting(4, [3, 5, 9, 6, 3, 7, 2], [3, 3, 2], [5, 9, 6, 7]),
+                findall(q, pivoting(4, [3, 5, 9, 6, 3, 7, 2], _, _), [q, q | _])'''):
+            return [{'id': 'unprotected_branch'}]
+
+        if prolog.engine.ask_truthTO(engine_id, '''\
+                pivoting(4, [3, 5, 9, 5, 2], [3, 2], [5, 9, 5]),
+                \+ pivoting(4, [3, 5, 4, 5, 2], _, _)'''):
+            return [{'id': 'duplicates_not_considered'}]
+
+        if prolog.engine.ask_truthTO(engine_id, '''\
+                pivoting(4, [5, 3], _, [5|yowza])
+                ;
+                pivoting(4, [3, 5], [3|yowza], _)'''):
+            return [{'id': 'arbitrary_solution'}]
+
+        if prolog.engine.ask_truthTO(engine_id,
+                'pivoting(4, [3, 5, 9, 5, 2], S, G), (S = [] ; G = [])'):
+            return [{'id': 'all_elements_in_either_S_or_G'}]
+
+        if prolog.engine.ask_truthTO(engine_id, '''\
+                \+ pivoting(4, [3, 5], _, _),
+                (asserta(pivoting(4, [5], [3, 5], [yowza])),
+                 pivoting(4, [3, 5], [5], [yowza]),
+                 retract(pivoting(4, [5], [3, 5], [yowza]))
+                 ;
+                 asserta(pivoting(4, [3], [yowza], [5, 3])),
+                 pivoting(4, [5, 3], [yowza], [3]),
+                 retract(pivoting(4, [3], [yowza], [5, 3])))'''):
+            return [{'id': 'forcing_result_onto_recursion'}]
+
+        # missing/failed base case
+        if not prolog.engine.ask_truthTO(engine_id, 'pivoting(_, [], [], [])'):
+            return [{'id': 'base_case'}]
+
+        # target predicate seems to always be false
+        if not prolog.engine.ask_truthTO(engine_id, 'pivoting(_, _, _, _)'):
+            return [{'id': 'predicate_always_false'}]
+
+        # base case works, the recursive doesn't (but it doesn't timeout)
+        # this may be left as the last, most generic hint
+        if not prolog.engine.ask_truth(engine_id,
+                'pivoting(4, [2, 1, 8, 9, 3, 4, 2], [2, 1, 3, 4, 2], [8, 9])'):
+            return [{'id': 'recursive_case'}]
+
+    except socket.timeout as ex:
+        return [{'id': 'timeout'}]
+
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
     return []