sourcing environment

[Tak Ota]

Hello,

I use emacs at work for embedded software development.  When switching
gears frequently between different cross compilation environment it is
common practice to set/change environment variables by sourcing shell
scripts.

Like many seasoned emacs users once I start emacs I don't want to
discontinue that process however to change environment I need to kill
the current emacs and source shell script to change environment and
restart emacs again.  To alleviate this annoying inconvenience I now
use the following custom function to tweak the environment on the fly.

(defun source (script &optional shell)
  "Source the specified shell script.
Source the shell SCRIPT and import the environment into this emacs.
The optional SHELL specifies the shell other than the default `shell-file-name'"
  (interactive "fscript file: ")
  (if (null shell)
      (setq shell shell-file-name))
  (with-temp-buffer
    (call-process shell nil t nil "-c" (concat "source " script "; printenv"))
    (while (re-search-backward "^\\([^=]+\\)=\\(.*\\)$" nil t)
      (setenv (match-string 1) (match-string 2)))))

Has there been something equivalent to this already built into some
existing scripts?  I bet many people have encountered this need.
Please educate my ignorance.

-Tak

P.S.

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