DSL EXPRESSION:
func f(var x, var y): var { var z = 3}


AST:
* statement block
    * function definition "f"
        * parameter list
            * parameter
                * parameter name "x"
                    * type declaration "var"
            * parameter
                * parameter name "y"
                    * type declaration "var"
        * statement block
            * assignment "="
                * local variable "z"
                    * type declaration "var"
                * int literal "3"
        * type declaration "var"

