#xyzzy lisp なバッファの *buffer-package* を保存時に設定とか

gistfile1.lisp

;;;;; set *buffer-package*

(defparameter *lisp-mode-family* '(lisp-mode lisp-interaction-mode)
  "lisp-mode な感じのメジャーモードたち（あちこちで定義してる気がする...）")

(defun find-buffer-package-from-magic-comment ()
  "-*- ... package: PACKAGE -*- を拾ってくる"
  (cdr (assoc "package" (ed::find-file-scan-params) :test #'string-equal)))

(defun set-buffer-package (&optional (package (find-buffer-package-from-magic-comment)))
  "lisp-mode などで参照するバッファ毎の現在のパッケージをセットする。"
  (interactive "sPackage: "
    :default0 (or (find-buffer-package-from-magic-comment)
                  *buffer-package*))
  (check-type package string)
  (setf *buffer-package* package))

(defun set-buffer-package-on-save ()
  "lisp-mode 等で、-*- .. Package: PACKAGE -*- があればセットする。
*after-save-buffer-hook* 等から実行する用。"
  (when (member buffer-mode *lisp-mode-family*)
    (let ((package (find-buffer-package-from-magic-comment)))
      (when package
        (setf *buffer-package* package)))))

(add-hook '*after-save-buffer-hook* 'set-buffer-package-on-save)