2 files changed, 30 insertions, 0 deletions
diff --git a/prolog/problems/lists_advanced/shiftleft_2/common.py b/prolog/problems/lists_advanced/shiftleft_2/common.py
index 77b66ca..2225bdd 100644
--- a/prolog/problems/lists_advanced/shiftleft_2/common.py
+++ b/prolog/problems/lists_advanced/shiftleft_2/common.py
@@ -23,6 +23,9 @@ hint_type = {
     'eq_instead_of_equ': Hint('eq_instead_of_equ'),
     'predicate_always_false': Hint('predicate_always_false'),
     'timeout': Hint('timeout'),
+    'conc_arg_not_list': Hint('conc_arg_not_list'),
+    'arbitrary_result': Hint('arbitrary_result'),
+    'tail_must_be_list': Hint('tail_must_be_list'),
 }
 
 test_cases = [
@@ -67,6 +70,21 @@ def hint(code, aux_code):
             return [{'id': 'eq_instead_of_equ_markup', 'start': m[0], 'end': m[1]} for m in marks] + \
                    [{'id': 'eq_instead_of_equ'}]
 
+        # arbitrary result
+        if prolog.engine.ask_truthTO(engine_id,
+                'shiftleft([27, 81, 243], granddad(Q, q))'):
+            return [{'id': 'arbitrary_result'}]
+
+        # conc/3 argument not a list
+        if prolog.engine.ask_truthTO(engine_id,
+                'shiftleft([9, 3, 1, 27, 81, 243], [3, 1, 27, 81, 243 | 9])'):
+            return [{'id': 'conc_arg_not_list'}]
+
+        # tail must be list
+        if prolog.engine.ask_truthTO(engine_id,
+                'shiftleft([27, 9, 3, 1, 81, 243], [[9, 3, 1, 81, 243] | 27])'):
+            return [{'id': 'tail_must_be_list'}]
+
         # target predicate seems to always be false
         if not prolog.engine.ask_truthTO(engine_id, 'shiftleft(_, _)'):
             return [{'id': 'predicate_always_false'}]
diff --git a/prolog/problems/lists_advanced/shiftleft_2/sl.py b/prolog/problems/lists_advanced/shiftleft_2/sl.py
index fc41e3c..ec55c4e 100644
--- a/prolog/problems/lists_advanced/shiftleft_2/sl.py
+++ b/prolog/problems/lists_advanced/shiftleft_2/sl.py
@@ -33,4 +33,16 @@ da je <code>X</code> hkrati starš in sestra od <code>Y</code> ali kaj podobno z
 <p>Je morda na delu potencialno neskončna rekurzija? Kako se bo ustavila?</p>
 <p>Morda pa je kriv tudi manjkajoč, neustrezen ali preprosto nekompatibilen (s splošnim primerom) robni pogoj?</p>
 ''',
+
+    'conc_arg_not_list': '''\
+<p>conc_arg_not_list</p>
+''',
+
+    'arbitrary_result': '''\
+<p>arbitrary_result</p>
+''',
+
+    'tail_must_be_list': '''\
+<p>tail_must_be_list</p>
+''',
 }