how to create a macro in racket where a list becomes the args of said lambda? -

how go in doing define-syntax-rule accepts list arguments , list (or quote, in case single element) body of lambda? like:

    >(define (lambdarize '(x y z) '(+ x y z)))     #<procedure>     >(a 1 2 3)     6     >(define b (lambdarize '(x) 'x))     #<procedure>     >(b 1)     1 

i have played around define-syntax-rule , apply, since lambda seems macro , not procedure, have been stumped @ trying find it...

oh... , solution not use eval, pernicious...

update

thanks answer, ryan... pretty did it! =) problem eval no @ catching current scope... way can stuff

    (let ([a 1])         (begin             (defmethod add ((x integer?) (y integer?)) (+ x y a))             (add 1 2)     ) 

which fail miserably eval... academic example, think test correctness.

it's not possible create function formal parameters , body given run-time values (s-expressions) without using eval.

but based on answer greg's comment, can change defmethod macro avoid issue. current approach takes variables , body expression (program terms), converts them run-time values, wants reinterpret them program terms. instead, should combine program terms lambda-expression in macro, can pass value helper function:

(define-syntax-rule (defmethod name ((var predicate) ...) body)   (add-to-generic name                   (list predicate ...)                   (lambda (var ...) body))) 

if wanted keep variable names around (eg error messages), can quote them, separate lambda-expression:

(define-syntax-rule (defmethod name ((var predicate) ...) body)   (add-to-generic name                   (list predicate ...)                   '(var ...)                 ;; errors, debugging, etc                   (lambda (var ...) body)))