Hello again.. I decided to go for Spirit to solve my problem (replacing $variable in string), and I made my own grammar to parse the string.. Now the problems that I have to face with and have no idea how to solve them: 1st) there should be keywords in the grammar/scanner class from some vector <string> which is outside the scanner class that scanner should look for (to be used with definition).. I have no idea what would be the right way to pass/give/read them from scanner class 2nd) when I find a match with scanner class I call [function(self.matched)].. How to pass 2 arguments or more? For instance I will have to pass 3 arguments from $random(1,2,3) + variable name.. so call_some_func("random", 1, 2, 3); How should I solve that? Maybe any example available? Thanks a lot for help Kind regards