From 49a2f24a813ca250d1c1f31f9799661ff70615ed Mon Sep 17 00:00:00 2001
From: Aleksander Sadikov <aleksander.sadikov@fri.uni-lj.si>
Date: Mon, 29 Feb 2016 00:11:26 +0100
Subject: Additional improvements to hints for mother, father, grandparent,
 sister, and brother problems.

---
 prolog/problems/family_relations/brother_2/common.py | 13 +++++++++----
 prolog/problems/family_relations/brother_2/sl.py     | 12 +++++++++---
 2 files changed, 18 insertions(+), 7 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 7f61744..0ad74c3 100644
--- a/prolog/problems/family_relations/brother_2/common.py
+++ b/prolog/problems/family_relations/brother_2/common.py
@@ -26,7 +26,8 @@ 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'),
+    'neq+_instead_of_neq': Hint('neq+_instead_of_neq'),
+    'predicate_always_false': Hint('predicate_always_false'),
 }
 
 test_cases = [
@@ -78,9 +79,13 @@ def hint(code, aux_code):
            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'}]
+        # use of \= or =\= instead of \==
+        if prolog.util.Token('NEQU', '\=') in tokens or prolog.util.Token('NEQA', '=\=') in tokens:
+            return [{'id': 'neq+_instead_of_neq'}]
+
+        # target predicate seems to always be false
+        if prolog.engine.ask_one(engine_id, 'brother(_, _)') == 'false':
+            return [{'id': 'predicate_always_false'}]
 
         # X and Y must be different
         if prolog.util.Token('NEQ', '\==') not in tokens and prolog.engine.ask_truth(engine_id,
diff --git a/prolog/problems/family_relations/brother_2/sl.py b/prolog/problems/family_relations/brother_2/sl.py
index f8eba49..ed2d015 100644
--- a/prolog/problems/family_relations/brother_2/sl.py
+++ b/prolog/problems/family_relations/brother_2/sl.py
@@ -46,9 +46,10 @@ Na primer: <code>X \== Y</code></p>
 <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>
+    'neq+_instead_of_neq': '''\
+<p>Uporabi raje operator \== namesto operatorjev \= ali =\=. Prvi preveri, da oba operanda nista enaka,
+drugi (\=) ju poskusi unificirati (narediti enaka), tretji (=\=) pa je samo za aritmetično primerjanje
+in morata oba operanda biti takoj izračunljiva aritmetična izraza.</p>
 ''',
 
     'common_parent_needed': '''\
@@ -65,4 +66,9 @@ ko naleti na primerjavo.</p>
 <p>Morda pa preprosto preverjaš napačni spremenljivki?</p>
 ''',
 
+    'predicate_always_false': '''\
+<p>Vse kaže, da tvoj predikat vedno vrne "false". Si mu dal pravilno ime, si se morda pri imenu zatipkal?</p>
+<p>Če je ime pravilno, se morda splača preveriti tudi, če se nisi zatipkal kje drugje,
+je morda kakšna pika namesto vejice ali obratno, morda kakšna spremenljivka z malo začetnico?</p>
+''',
 }
-- 
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