adding support for tag in Throw/Catch

Author: mmatera

mathics/builtin/control.py

@@ -767,7 +767,11 @@ def apply3(self, expr, form, f, evaluation):
         except WLThrowInterrupt as e:
             # TODO: check that form match tag.
             # otherwise, re-raise the exception
-            return Expression(f, e.value)
+            match = Expression("MatchQ", e.tag, form).evaluate(evaluation)
+            if match.is_true():
+                return Expression(f, e.value)
+            else:
+                raise e
         return ret