From 913007d3f60d86c3f4e11733153233434da8607f Mon Sep 17 00:00:00 2001
From: Aleksander Sadikov <aleksander.sadikov@fri.uni-lj.si>
Date: Wed, 9 Mar 2016 19:48:21 +0100
Subject: Hints for del/3 updated.

---
 prolog/problems/lists/del_3/common.py | 6 ++++++
 prolog/problems/lists/del_3/sl.py     | 4 ++++
 2 files changed, 10 insertions(+)

(limited to 'prolog')

diff --git a/prolog/problems/lists/del_3/common.py b/prolog/problems/lists/del_3/common.py
index f3dfcb2..c984fef 100644
--- a/prolog/problems/lists/del_3/common.py
+++ b/prolog/problems/lists/del_3/common.py
@@ -27,6 +27,7 @@ hint_type = {
     'final_hint': Hint('final_hint'),
     'del_from_empty_list_success': Hint('del_from_empty_list_success'),
     'lost_heads': Hint('lost_heads'),
+    'recursive_case': Hint('recursive_case'),
 }
 
 test_cases = [
@@ -97,6 +98,11 @@ def hint(code, aux_code):
         # L=[H|T] at the end of the rule; this can be detected with test cases and can be wrong (in some sense)
         # TODO: implement it, and provide a good explanation (might be hard)
 
+        # base case works, the recursive doesn't (but it doesn't timeout)
+        # this may be left as the last, most generic hint
+        if not prolog.engine.ask_truth(engine_id, 'del(qQ, [qa,qb,qQ,qc], [qa,qb,qc])'):
+            return [{'id': 'recursive_case'}]
+
 
     except socket.timeout as ex:
         return [{'id': 'timeout'}]
diff --git a/prolog/problems/lists/del_3/sl.py b/prolog/problems/lists/del_3/sl.py
index 5fa8e17..0875fe0 100644
--- a/prolog/problems/lists/del_3/sl.py
+++ b/prolog/problems/lists/del_3/sl.py
@@ -46,6 +46,10 @@ implicitno že kar v argumentih predikata (glavi stavka).</p>
 
     'base_case': '''\
 <p>Si pomislil na robni pogoj? Kaj je najbolj enostaven primer, kateri element v seznamu najlažje zbrišeš?</p>
+''',
+
+    'recursive_case': '''\
+<p>Robni primer deluje. Kaj pa rekurzivni, splošni, primer?</p>
 ''',
 
     'predicate_always_false': '''\
-- 
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