Set PATH properly in macOS

[li-yiyang]

If starting from Lem.app on macOS, the PATH may not complete so uiop:launch-program or uiop:run-program would not work (if rely on homebrew). The following function can help extract correct PATH information and set it if needed.

(defun env-path ()
  "Return the PATH environment variable value. 

For macOS, it should be composed from: 
+ /etc/paths
+ /etc/paths.d/*

For linux, it should be $PATH variable directly. "
  #+darwin
  (with-output-to-string (stream)
    (flet ((read-f (f)
             (with-open-file (path f) 
               (loop :for line := (read-line path nil :eof)
                     :until (eq line :eof)
                     :do (write-string line stream)
                     :do (write-char   #\:  stream)))))
      (loop :for f :in (uiop:directory-files #P"/etc/paths.d/")
            :do (read-f f))
      (read-f #P"/etc/paths")))
  #+linux
  (uiop:getenv "PATH")
  #-(or darwin linux)
  "")

;;; PATH should be injected properly

#+darwin
(add-hook *after-init-hook* (lambda () (setf (uiop:getenv "PATH") (env-path))))

Other solutions:

• use open -a Lem.app from terminal
• Emacs (emacs-plus) inject PATH in .plist as Application configuration

[cianoc]

Nice!

This would be useful as a pull request I think.

[li-yiyang]

A PR (#1866) had been created.

But i think its API should be polished. The new implemented API exec-path is copied from Emacs.