You can do function calls in a form of BNF.

declare_stmt    ::= "DECLARE" ("SUB" alnum+ | "FUNCTION" alnum+ suffix)


                    "(" func_arg ("," func_arg)* ")"


func_arg        ::= dim_expr | alpha alnum+ suffix


dim_expr        ::= alpha alnum+ ("(" dimensions ")")? "AS" typename


alnum           ::= alpha | [0-9]


alpha           ::= [A-Za-z]


suffix          ::= "%" | "!" | "&" | "#" | "$"


typename        ::= "INTEGER" | "LONG" | "SINGLE" | "DOUBLE" | "STRING"

No, that's not complete, nor is it even halfway correct. I simply did it to show how amazingly annoying it would be to do it. With the way QB is structured, it is rather difficult to do. Oh, and did I mention that I didn't even think about spacing between tokens, never mind the whole bit where you can separate things onto multiple lines using the underscore at the end of a line (assuming you're not in the interpreter)?

QB's grammar is a mess, no matter how clean it appears to be. I'd recommend that you not waste your time unless you seriously have nothing better to do.