 Or call a lambda.
;; (define-syntax standard-let
;;
;;   (syntax-rules ()
;;
;;     ((let ((var val) ...) body ...)
;;      ((lambda (var ...) body ...) val ...))))

(define-syntax let

  (syntax-rules ()

    ;; No bindings: use standard-let.
    ((let () body ...)
     (standard-let () body ...))
    ;; Or call a lambda.
    ;; ((lambda () body ...))

    ;; All standard bindings: use standard-let.
    ((let ((var val) ...) body ...)
     (standard-let ((var val) ...) body ...))
    ;; Or call a lambda.
