Improved hints for ancestor/2.

1 files changed, 8 insertions, 8 deletions

diff --git a/prolog/problems/family_relations/ancestor_2/common.py b/prolog/problems/family_relations/ancestor_2/common.py
index 3b70227..d2e4f76 100644
--- a/prolog/problems/family_relations/ancestor_2/common.py
+++ b/prolog/problems/family_relations/ancestor_2/common.py
@@ -89,23 +89,23 @@ def hint(code, aux_code):
             return [{'id': 'base_case'}]
 
         # ancestor to oneself
-        if prolog.engine.ask_truth(engine_id, 'ancestor(X, X)'):
+        if prolog.engine.ask_truthTO(engine_id, 'ancestor(X, X)'):
             return [{'id': 'ancestor_to_oneself'}]
 
-        # Y does not necessarily need to be a parent
-        if prolog.engine.ask_one(engine_id,
-            'ancestor(_, Y), \+ parent(Y, _)') == 'false':
-            return [{'id': 'descendant_need_not_be_parent'}]
-
         # descendant instead of ancestor (wrong direction)
         # warning: knowledge base dependent
-        if prolog.engine.ask_truth(engine_id,
+        if prolog.engine.ask_truthTO(engine_id,
             'findall(_, ancestor(william, X), L1), length(L1, 2), \
              findall(_, ancestor(X, william), L2), length(L2, 6)'):
             return [{'id': 'wrong_direction'}]
 
+        # Y does not necessarily need to be a parent
+        if prolog.engine.ask_one(engine_id,
+            'ancestor(_, Y), \+ parent(Y, _)') == 'false':
+            return [{'id': 'descendant_need_not_be_parent'}]
+
     except socket.timeout as ex:
-        return [{'id': 'base_case'}]
+        pass
 
     finally:
         if engine_id: