From 500dae272daabdb5e9272d3e54111aea5e109c3b Mon Sep 17 00:00:00 2001
From: Aleksander Sadikov <aleksander.sadikov@fri.uni-lj.si>
Date: Mon, 29 Feb 2016 20:56:12 +0100
Subject: Improved hints for ancestor/2. "Timeout results as False"
 ask_truthTO() function added.

---
 prolog/engine.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/prolog/engine.py b/prolog/engine.py
index b023c9e..cebadea 100644
--- a/prolog/engine.py
+++ b/prolog/engine.py
@@ -211,6 +211,30 @@ def ask_truth(engine, query, timeout=1):
         # no error, query failed
         return False
 
+def ask_truthTO(engine, query, timeout=1):
+    # Returns either True or False
+    # (Runtime) error is False!
+    # Timeout *is* handled:  returned as False
+
+    # Run the query.
+    try:
+        reply, output = ask(engine, query, timeout)
+    except socket.timeout as ex:
+        return False
+
+    if 'error' in map(itemgetter(0), output):
+        return False
+        # TODO: Tim, this doesn't really work. It just proceeds and returns as a runtime error.
+    answer, error, more = process_answer(reply)
+    if error:
+        # query caused a runtime error
+        return False
+    elif answer:
+        return True
+    else:
+        # no error, query failed
+        return False
+
 # reformats prolog's answer into a neater form
 def process_answer(reply):
         # When an engine is destroyed, a nested data object has the actual
-- 
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