From fa58ab7b297d1df467ac3a4b77397b3ca05325e9 Mon Sep 17 00:00:00 2001
From: Timotej Lazar <timotej.lazar@fri.uni-lj.si>
Date: Mon, 30 Nov 2015 15:19:22 +0100
Subject: Limit the number of inferences for Prolog queries

---
 prolog/engine.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'prolog/engine.py')

diff --git a/prolog/engine.py b/prolog/engine.py
index bd1fb1d..d61c43b 100644
--- a/prolog/engine.py
+++ b/prolog/engine.py
@@ -132,8 +132,11 @@ def check_answers(engine, query, answers, timeout=10):
 
     start = time.monotonic()
     try:
+        # Limit inferences for each solution to curb unbounded recursion.
+        limited = '''(call_with_inference_limit(({}), 100000, _ILR),
+                      _ILR \= inference_limit_exceeded)'''.format(query)
         # Run the query.
-        reply, output = ask(engine, query, timeout)
+        reply, output = ask(engine, limited, timeout)
         answer, error, more = process_answer(reply)
         if not check_answer(answer):
             return False
-- 
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