コマンドを実行することで変更される環境変数を取得する #xyzzy

gistfile1.cl

;; detect-environment-changes
;;   指定したコマンド実行後に変更された環境変数を取得する
;;
;; environment
;;   現在のプロセスの環境変数を取得する
;;
;; system
;;   指定したコマンドを実行し、実行結果と実行後の環境変数を取得する

(defconstant +boundary+ "--- pik --- pik --- pik --- pik ---")

(defun system (command args &key dump-env)
  (flet ((q (s)
           (if (string-matchp "[&<>()@^| ]" s)
               (format nil "\"~A\"" s)
             s)))
    (let ((cmd (format nil "\"~A ~{~A~^ ~}\"~@[ && echo ~*~A && set~]" (q command) (mapcar #'q args) dump-env +boundary+))
          (buf (get-buffer-create "*Pik Output*")))
      (erase-buffer buf)
      (unwind-protect
          (let ((status (save-window-excursion
                          (execute-shell-command cmd nil buf))))
            (with-set-buffer
              (set-buffer buf)
              (let ((output (buffer-substring (point-min)
                                              (if dump-env
                                                  (and (scan-buffer +boundary+ :tail nil)
                                                       (prog1
                                                           (point)
                                                         (forward-line)))
                                                (point-max))))
                    (env (when dump-env
                           (buffer-substring (point) (point-max)))))
                (values status output env))))
        (delete-buffer buf)))))

(defun parse-env (output)
  (mapcar #'(lambda (line)
              (let ((kv (split-string line #\= 2)))
                (cons (car kv) (cadr kv))))
          (split-string output #\LFD)))

(defun environment ()
  (multiple-value-bind (status output env)
      (system "set" nil)
    (parse-env output)))

(defun detect-environment-changes (cmd opts)
  (set-difference (multiple-value-bind (_ _ e)
                      (system cmd opts :dump-env t)
                    (parse-env e))
                  (environment)
                  :test 'equal))

gistfile2.cl

;; Usage
(detect-environment-changes
 (merge-pathnames "vsvars32.bat" (si:getenv "VS100COMNTOOLS"))
 nil)