cl-user> (cat "/tmp/g.lisp")
(defun generate-val (obj key) `(jsown:val ,obj ,key))

(defmacro with-jsown-vals (obj vals &body body)
  "Provides the passed jsown values as local variables within the scope to be used."
  `(let ,(mapcar #'(lambda (key) (list (intern (string-upcase key)) (generate-val obj key))) vals)
     ,@body))

(pprint (macroexpand-1 '(with-jsown-vals *js* (list "b" "a") (format t "~A" a))))
; No value
cl-user> (load "/tmp/g.lisp")

(let ((list (jsown:val *js* list)) (b (jsown:val *js* "b")) (a (jsown:val *js* "a"))) (format t "~A" a))
#P"/private/tmp/g.lisp"
cl-user>