sister/2 and brother/2 hints improved.

1 files changed, 7 insertions, 2 deletions

diff --git a/prolog/problems/family_relations/sister_2/common.py b/prolog/problems/family_relations/sister_2/common.py
index 08f44b3..1bc9365 100644
--- a/prolog/problems/family_relations/sister_2/common.py
+++ b/prolog/problems/family_relations/sister_2/common.py
@@ -26,6 +26,7 @@ hint_type = {
     'y_can_be_of_any_gender': Hint('y_can_be_of_any_gender'),
     'x_y_must_be_different': Hint('x_y_must_be_different'),
     'neq_used_too_early': Hint('neq_used_too_early'),
+    'nm_instead_of_neq': Hint('nm_instead_of_neq'),
 }
 
 test_cases = [
@@ -102,10 +103,14 @@ def hint(code, aux_code):
         # as this is after previous hints, by this stage the code probably
         # does return some sensible results already
         # this is an example of using the ordering of hints for easier trigger checks
-        if prolog.engine.ask_one(engine_id,
-            'sister(_, Y), male(Y)') == 'false':
+        if prolog.engine.ask_truth(engine_id, 'sister(_, Y)') and \
+           prolog.engine.ask_one(engine_id, 'sister(_, Y), male(Y)') == 'false':
             return [{'id': 'y_can_be_of_any_gender'}]
 
+        # use of \= instead of \==
+        if prolog.util.Token('NEQ', '\=') in tokens:
+            return [{'id': 'nm_instead_of_neq'}]
+
         # X and Y must be different
         # this is the last code-specific hint (when everything else doesn't trigger anymore)
         if prolog.util.Token('NEQ', '\==') not in tokens and prolog.engine.ask_truth(engine_id,