I want to make a helper macro for writing match-extensions. I have something like this:

(define-match-expander my-expander
  (? (stx)
    (let* ([dat (cdr (syntax-e stx))]
           [var1 (car dat))]
           [var2 (cadr dat)])
      ;transformer goes here )))

So I wanted a macro that will do this let binding. I've started with something like this:

(define-syntax-rule (define-my-expander (id vars ...) body)
  (define-match-expander id
    (? (stx)
      (match-let ([(vars ...) (cdr (syntax-e stx))])
        body))))

but match-let isn't defined in transformation time.

First question would be is there any other way of doing this (making this expanders, I mean)? Maybe there is already something similar in plt-scheme that I'm not aware of, or I'm doing it wrong in some way.

Regardless of answer on the first question, if I ever want to bound list of variables to list of values inside of a macro, how should I do it?

EDIT: In combination with Eli's answer macro now looks like this:

(define-syntax-rule (define-my-expander (id vars ...) body)
  (define-match-expander id
    (? (stx)
      (syntax-case stx ()
        [(_ vars ...)
         body]))))