<div class="h5"> </div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">I meant in the argument to `datum->syntax'... </blockquote></div> Ah, great, this is even better. I can't believe its so small in the end... For the sake of it, here is what we have now: #lang racket (provide define-syntax-rule/id) ;;; By Jon Rafkind (+ tweakings) ;; Like define-syntax-rule, but takes an additional ([id id-rename] ...) set ;; where the id can be used in body, ;; and each id in body is replaced by the result of the id-rename expression. (define-syntax (define-syntax-rule/id stx) � (syntax-case stx () �� [(_ (name arg ...) �� ([id id-rename] ...) �� body ...) �� #'(define-syntax (name stx2) �� (syntax-case stx2 () �� [(_ arg ...) ; This comes from above! �� ; We want the defined ids to have the same lexical scope as �� ; the defined macro itself. �� (with-syntax ([id (datum->syntax �� stx2 �� (string->symbol �� ; id-rename is an expression that comes from above. �� ; it will be replaced by its code in the first expansion �� ; (the first syntax-case), �� ; and this code will be executed in the second expansion. �� (let ([arg (syntax-e #'arg)] ...) �� id-rename)) �� stx2 stx2 stx2 �� )] �� ...) �� ; id is correctly bound in body here because �� ; body is replaced by the full expression (containing id) �� ; in this submacro (just like for id-rename). �� #'(begin body ...))])) �� ])) #| TESTS: |# ; use the macro stepper to see how it is expanded (define-syntax-rule/id (make-getter-setter xid1 xid2) � ([getter (format "get-~a-~a" xid1 xid2)] �� [setter (format "set-~a-~a" xid1 xid2)] �� [xchger (format "xch-~a-~a" xid1 xid2)]) � (define (getter) (values xid1 xid2)) � (define (setter v1 v2) (set! xid1 v1) (set! xid2 v2)) � (define (xchger) (setter xid2 xid1)) � ) (define x1 5) (define x2 6) (make-getter-setter x1 x2) (get-x1-x2) (set-x1-x2 10 11) (get-x1-x2) (xch-x1-x2) (get-x1-x2) ;|#