gistfile1.sls

(defun make-stat-env (params &optional env)
   (append
    (loop
    for var in params
    for j = 1 then (+ j 1)
    for num-env = (if (or (eq (first env) '&optional)
                          (eq (first env) '&rest)) nil (+ (or (second (first env)) -1) 1))
    collect (list var num-env j)
    )
    env))


(make-stat-env '(a b &optional c)) => ((A 0 1) (B 0 2) (&OPTIONAL 0 3) (C 0 4))