WIP: add a Val struct as an input/output when calling a function

src/env.h

@@ -145,6 +145,10 @@ struct Stack
 
 struct Env
 {
+	// a result consists of a string and a boolean value
+	// output stream
+	pt::Stream & out; // OLD INTERFACE a reference to res.stream
+
 	// table of parameters
 	// the table can be empty
 	std::vector<Val> & params;
@@ -156,9 +160,6 @@ struct Env
 	// old interface but still available
 	//
 
-	// a result consists of a string and a boolean value
-	// output stream
-	pt::Stream & out; // OLD INTERFACE a reference to res.stream
 	// return value from a user's function (default false if not set directly by the function)
 	//bool res;