From bc40d810afbcde332730d50ed490deb432689db1 Mon Sep 17 00:00:00 2001
From: Aleksander Sadikov <aleksander.sadikov@fri.uni-lj.si>
Date: Sun, 28 Feb 2016 22:14:02 +0100
Subject: sister/2 and brother/2 hints improved.

---
 prolog/problems/family_relations/brother_2/common.py | 9 +++++++--
 prolog/problems/family_relations/brother_2/sl.py     | 6 ++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

(limited to 'prolog/problems/family_relations/brother_2')

diff --git a/prolog/problems/family_relations/brother_2/common.py b/prolog/problems/family_relations/brother_2/common.py
index c49489e..7f61744 100644
--- a/prolog/problems/family_relations/brother_2/common.py
+++ b/prolog/problems/family_relations/brother_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 = [
@@ -73,10 +74,14 @@ def hint(code, aux_code):
             return [{'id': 'common_parent_needed'}]
 
         # Y can be of any gender, incl. female
-        if prolog.engine.ask_one(engine_id,
-            'brother(_, Y), female(Y)') == 'false':
+        if prolog.engine.ask_truth(engine_id, 'brother(_, Y)') and \
+           prolog.engine.ask_one(engine_id, 'brother(_, Y), female(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
         if prolog.util.Token('NEQ', '\==') not in tokens and prolog.engine.ask_truth(engine_id,
             'setof(X, (member(X, [william, alessandro, andrew]), brother(X, X)), L), length(L, 3)'):
diff --git a/prolog/problems/family_relations/brother_2/sl.py b/prolog/problems/family_relations/brother_2/sl.py
index 2d170aa..f8eba49 100644
--- a/prolog/problems/family_relations/brother_2/sl.py
+++ b/prolog/problems/family_relations/brother_2/sl.py
@@ -44,6 +44,11 @@ Na primer: <code>X \== Y</code></p>
 
     'y_can_be_of_any_gender': '''\
 <p><code>Y</code> je pravzaprav lahko poljubnega spola.</p>
+''',
+
+    'nm_instead_of_neq': '''\
+<p>Uporabi raje operator \== namesto operatorja \=. Prvi preveri, da dva objekta nista enaka,
+drugi pa ju poskusi unificirati (narediti enaka).</p>
 ''',
 
     'common_parent_needed': '''\
@@ -57,6 +62,7 @@ Na primer: <code>X \== Y</code></p>
 da spremenljivki, ki ju primerjaš, še nimata določene vrednosti in sta zato različni.
 Prolog ne preverja, če kasneje morda postaneta enaki, ampak samo kakšni sta v trenutku,
 ko naleti na primerjavo.</p>
+<p>Morda pa preprosto preverjaš napačni spremenljivki?</p>
 ''',
 
 }
-- 
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