Adds support to custom operator's message in case of a match

src/operators/operator.h

@@ -50,6 +50,8 @@ class Operator {
     virtual bool evaluate(Transaction *transaction, const std::string &str);
     static Operator *instantiate(std::string op);
 
+    std::string m_match_message;
+
  protected:
     bool debug(Transaction *transaction, int x, std::string a);
 };