Additional improvements to hints for mother, father, grandparent, sister, and brother problems.

1 files changed, 4 insertions, 4 deletions

diff --git a/prolog/problems/family_relations/father_2/common.py b/prolog/problems/family_relations/father_2/common.py
index 11f0742..31109c9 100644
--- a/prolog/problems/family_relations/father_2/common.py
+++ b/prolog/problems/family_relations/father_2/common.py
@@ -67,6 +67,10 @@ def hint(code, aux_code):
     try:
         engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0)
 
+        # target predicate seems to always be false
+        if not prolog.engine.ask_truth(engine_id, 'father(_, _)'):
+            return [{'id': 'predicate_always_false'}]
+
         # OR (;) instead of AND (,)
         # this hint has to be before the next two
         # as otherwise those two would always override it
@@ -102,10 +106,6 @@ def hint(code, aux_code):
            prolog.engine.ask_one(engine_id, 'father(_, Y), \+ parent(Y, _)') == 'false':
             return [{'id': 'y_need_not_be_parent'}]
 
-        # target predicate seems to always be false
-        if prolog.engine.ask_one(engine_id, 'father(_, _)') == 'false':
-            return [{'id': 'predicate_always_false'}]
-
     except socket.timeout as ex:
         pass