adding cache_eval to the Evaluation object

mmatera · mmatera · commit ceecb4b3c0b7 · 2021-06-29T18:45:59.000-03:00
diff --git a/mathics/core/evaluation.py b/mathics/core/evaluation.py
@@ -264,6 +264,8 @@ def __init__(
         # Necesary to handle OneIdentity on
         # lhs in assignment
         self.ignore_oneidentity = False
+        self.cache_eval = {}
+
 
     def parse(self, query):
         "Parse a single expression and print the messages."
