Replace prolog.engine.ask_all with check_answers

When testing a program we can stop searching for new solutions after we
have received a wrong one.

1 files changed, 20 insertions, 23 deletions

diff --git a/prolog/engine.py b/prolog/engine.py
index 50582c8..eca0826 100644
--- a/prolog/engine.py
+++ b/prolog/engine.py
@@ -6,7 +6,6 @@ import http.client
 import json
 from operator import itemgetter
 import re
-import socket
 import time
 import urllib
 
@@ -112,46 +111,45 @@ def pretty_vars(data):
         result += [strip_html(b) for b in data['residuals']]
     return ',\n'.join(result) if result else 'true'
 
-# Run [query] in the pengine with id [engine] and return the list of answers
-# found within [timeout] seconds. If a timeout occurs before the query is done,
-# 'timed out' is appended as the last answer.
-def ask_all(engine, query, timeout=10):
-    # Returns a tuple ((bindings, constraints), error, more?) for one answer.
+# Run [query] in pengine with ID [engine] and check whether all solutions
+# specified by [answers] (a list of binding dictionaries) are returned. This
+# function succeeds if [query] finds each solution in [answers] at least once
+# within [timeout] seconds, and fails when it finds any other solution.
+def check_answers(engine, query, answers, timeout=10):
+    seen = []
     start = time.monotonic()
-    answers, messages = [], []
     try:
         # Run the query.
         reply, output = ask(engine, query, timeout)
-        messages += output
-        if 'error' in map(itemgetter(0), output):
-            return answers, messages
         answer, error, more = process_answer(reply)
         if answer:
-            answers.append(answer)
-        if error:
-            messages.append(error)
+            bindings, constraints = answer
+            if bindings not in answers:
+                return False
+            if bindings not in seen:
+                seen.append(bindings)
 
         # Continue while there are more potential answers and time remaining.
         while more:
             real_timeout = timeout - (time.monotonic()-start)
             if real_timeout <= 0:
-                raise socket.timeout()
+                break
             reply, output = next(engine, timeout=real_timeout)
-            messages += output
             answer, error, more = process_answer(reply)
             if answer:
-                answers.append(answer)
-            if error:
-                messages.append(error)
-    except socket.timeout as ex:
-        answers.append('timed out')
-    return answers, messages
+                bindings, constraints = answer
+                if bindings not in answers:
+                    return False
+                if bindings not in seen:
+                    seen.append(bindings)
+    except:
+        pass
+    return len(seen) == len(answers)
 
 # Run [query] in the pengine with id [engine] and return the first answer only
 # found within [timeout] seconds.
 # used for quick hint debugging by Sasha
 def ask_one(engine, query, timeout=1):
-    # quicker than ask_all as there could be many hint-triggering tests
     # Returns either an error message, true, false, timeout (see below), or bindings
     # Timeout is "returned" as an unhandled exception -- deliberately so
 
@@ -175,7 +173,6 @@ def ask_one(engine, query, timeout=1):
         return 'false'
 
 def ask_truth(engine, query, timeout=1):
-    # quicker than ask_all as there could be many hint-triggering tests
     # Returns either True or False
     # (Runtime) error is False!
     # Timeout is an unhandled exception -- deliberately so