(set-exec-path-from-shell-PATH)

  (fwoar/source "~/.zshrc")

(defun fwoar/source (filename)
  "Update environment variables from a shell source file."
  (interactive "fSource file: ")
  (message "Sourcing environment from `%s'..." filename)
  (with-temp-buffer
    (shell-command (format "diff -u <(true; export) <(source %s; export)" filename) '(4))
    (let ((envvar-re "\\([^=[:space:]]+\\)=\\(.*\\)$"))
      ;; Remove environment variables
      (while (search-forward-regexp (concat "^-" envvar-re) nil t)
        (let ((var (match-string 1)))
          (message "%s" (prin1-to-string `(setenv ,var nil)))
          (setenv var nil)
          ))
      ;; Update environment variables
      (goto-char (point-min))
      (while (search-forward-regexp (concat "^+" envvar-re) nil t)
        (let ((var (match-string 1))
              (value (string-trim (match-string 2) "'" "'")))
          (message "%s" (prin1-to-string `(setenv ,var ,value)))
          (setenv var value)
          ))))
  (message "Sourcing environment from `%s'... done." filename))

                                     ("melpa" . 2)
                                     ("nongnu" . 3)))

                                     ("nongnu" . 2)
                                     ("melpa" . 3)))