1 files changed, 42 insertions, 1 deletions
diff --git a/prolog/problems/lists/conc_3/common.py b/prolog/problems/lists/conc_3/common.py
index 67f9481..ce81bbe 100644
--- a/prolog/problems/lists/conc_3/common.py
+++ b/prolog/problems/lists/conc_3/common.py
@@ -18,6 +18,15 @@ conc([H|T], L2, [H|L]) :-
   conc(T, L2, L).
 '''
 
+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'),
+    'timeout': Hint('timeout'),
+    'final_hint': Hint('final_hint'),
+}
+
 test_cases = [
     ('conc([j, b], [l], X)',
         [{'X': '[j, b, l]'}]),
@@ -46,8 +55,40 @@ def test(code, aux_code):
             prolog.engine.destroy(engine_id)
 
     hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_cases)}}]
+    if n_correct == len(test_cases):
+        hints += [{'id': 'final_hint'}]
     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'}]
+
+        # recursion is getting bigger and bigger
+
+
+        # missing/failed base case
+        if not prolog.engine.ask_truthTO(engine_id, 'memb(qq, [qq,_,_,_])'):
+            return [{'id': 'base_case'}]
+
+        # target predicate seems to always be false
+        if not prolog.engine.ask_truth(engine_id, 'memb(_, [_,_,_,_,_,_])'):
+            return [{'id': 'predicate_always_false'}]
+
+    except socket.timeout as ex:
+        return [{'id': 'timeout'}]
+
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
     return []