(define-syntax let-optionals*
  (syntax-rules ()
    ((_ ?args ((?var0 ?default0) ?more-bindings ...) ?body ...)
     (let ((tmp ?args))
       (let ((?var0 (if (null? tmp) ?default0 (car tmp))))
         (let-optionals* (if (null? tmp) '() (cdr tmp)) (?more-bindings ...)
           ?body ...))))
    ((_ ?args (?rest) ?body ...)
     (let ((?rest ?args))
       ?body ...))))