From ee50df2225a974857e74d5ecb7c5f503e1c6b18a Mon Sep 17 00:00:00 2001
From: Aleksander Sadikov <sasha@fri.uni-lj.si>
Date: Thu, 10 Sep 2015 20:39:02 +0200
Subject: Hints for mother, father, brother, and sister added.

---
 .../problems/family_relations/sister_2/common.py   | 92 +++++++++++++++++++++-
 prolog/problems/family_relations/sister_2/sl.py    | 11 ++-
 2 files changed, 98 insertions(+), 5 deletions(-)

(limited to 'prolog/problems/family_relations/sister_2')

diff --git a/prolog/problems/family_relations/sister_2/common.py b/prolog/problems/family_relations/sister_2/common.py
index 96ff47d..e18a092 100644
--- a/prolog/problems/family_relations/sister_2/common.py
+++ b/prolog/problems/family_relations/sister_2/common.py
@@ -15,6 +15,7 @@ sister(X, Y) :-
 '''
 
 import prolog.engine
+import prolog.util
 import server.problems
 
 def test(session, program):
@@ -46,7 +47,94 @@ def test(session, program):
 
     return n_correct, len(queries)
 
+def general_hint():
+    pass
+
 def hint(session, program):
-    if '\=' not in program and '\==' not in program:
-        return [{'id': 'x_y_must_be_different'}]
+    # how do I know which general hints were already shown?
+    # how do I know enough time has elapsed for general hints to be shown?
+    # how do I know whether the hint button was pressed?
+    # should we have another hint button which appears in hint window (like more...)
+    #   when a hint is available after testing the current version of the program
+    #   and this button triggers code-specific hints (i.e. non-general ones)
+
+    # one way to do hints is to use a hierarchy of hints...
+    # similar to how some rule-based systems work
+    # the trigger-testing could be easier that way as well
+    # what I have in mind is:
+    # e.g. when I test if X is sister to itself, I've already done other trigger-tests
+    # and I don't need to do them again
+
+    # first general hints (triggered by the hint button)
+    # do we do it like this? this button triggers general hints only?
+    # not sure this is ok.. discuss with others (include Janez)
+
+    # if hbutton.pressed:
+        # trigger generalhint(#buttonpress)
+
+    # code-specific hints next
+
+    # tokenize (and similar) only if *needed* for a given exercise
+    # to reduce server processor load
+    tokens = prolog.util.tokenize(program)
+
+    # start the engine to unit-test triggers for hints
+    code = program + '\n' + server.problems.load_facts('prolog', facts).facts
+    engine_id = None
+    try:
+        engine_id, output = prolog.engine.create(code=code, timeout=1.0)
+        if not engine_id:
+            raise Exception('Prolog engine failed to create.')
+
+        # X must be female
+        if prolog.engine.ask_truth(engine_id, 'male(X), sister(X, _)'):
+            return [{'id': 'x_must_be_female'}]
+
+        # X and Y must have a common parent
+        if prolog.engine.ask_truth(engine_id,
+            'sister(X, Y), \+ (parent(P, X), parent(P, Y))'):
+            return [{'id': 'common_parent_needed'}]
+
+        # Y can be of any gender, incl. male
+        # 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':
+            return [{'id': 'Y_can_be_of_any_gender'}]
+
+        # X and Y must be different
+        # this is the last code-specific hint (when everything else doesn't trigger anymore)
+        ans = prolog.engine.ask_one(engine_id,
+            'setof(X, (member(X, [sally, nevia, vanessa]), sister(X, X)), L), length(L, N).')
+        if ans.get('N') == '3':
+            return [{'id': 'x_y_must_be_different'}]
+
+        # last hints are connected with programming style
+        # here, this means detecting such code:
+        # parent(P1, X), parent(P2, Y), P1 == P2 (or P1 = P2)
+        # I guess program tokens can be used for this
+        # do we require that the program is correct for this?
+        # or is it enough that this is after ALL code-specific hints AND it has to trigger?
+
+        # regular expressions, anyone?
+
+        # QUESTION to discuss:
+        # where do AI hints come into play?
+        # only after all code-specific and non stylistic hints are exhausted?
+        # or randomly before? or?
+
+        # QUESTION to discuss:
+        # I suggest hint triggers (if code-based or also token-based?)
+        # are used as CLASSES of unit tests
+        # although.. this makes random counterexamples harder to implement
+        # (does it?)
+
+    except socket.timeout as ex:
+        pass
+
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
     return None
diff --git a/prolog/problems/family_relations/sister_2/sl.py b/prolog/problems/family_relations/sister_2/sl.py
index c867567..5965bda 100644
--- a/prolog/problems/family_relations/sister_2/sl.py
+++ b/prolog/problems/family_relations/sister_2/sl.py
@@ -13,15 +13,20 @@ description = '''\
 
 hint = {
     'general_hint_1': '''\
-<p>Show Fig. #1 here.</p>
+<p><img src="Sister-1.png" /></p>
 ''',
 
     'general_hint_2': '''\
-<p>Show Fig. #2 here.</p>
+<p><img src="Sister-2.png" /></p>
 ''',
 
     'general_hint_3': '''\
-<p>Show Fig. #3 here.</p>
+<p><img src="Sister-2.png" /></p>
+<pre>
+parent(P, X)
+parent(P, Y)
+female(X)
+</pre>
 ''',
 
     'x_y_must_be_different': '''\
-- 
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