Run Python script with after-save-hook

Question

I wrote a Python script to parse an org file that I keep my tasks in, reformat those tasks, and save them to a taskpaper file so that I can easily view and process the tasks on my phone. The script works the way I want it to, but I have to rememeber to run it every time I want my tasks to 'sync'. I have been trying to use after-save-hook to run the script whenever I save changes to my org file, but I haven't been able to get it to work. I am new to Emacs, and don't know much about lisp. This is what I have come up with based mostly on the answer to this question.

(defun sync-to-taskpaper ()
  "Sync org file to taskpaper file for mobile access"
  (when (eq buffer-file-name "~/path/to/org/file.org")
    (shell-command "python3 ~/path/to/python/script.py")))

(add-hook 'after-save-hook #'sync-to-taskpaper)

I am not getting any error messages when I save the file, it just is not running my custom function. Is it possible to do it this way, and if so, what am I missing? Thank you for your help!

Answer 1

This is a mistake: (eq buffer-file-name "~/path/to/org/file.org").

Do not compare file names or any other strings using eq. See the Elisp manual, node Equality Predicates.

For strings, use string= or equal. For file names, use file-equal-p.

Here is another function that I also use to compare filenames, to see whether they reference the same file. It avoids accessing remote files when possible.

(defun same-file-p (file1 file2)
  "Return non-nil if FILE1 and FILE2 name the same file.
If either name is not absolute, then it is expanded relative to
`default-directory' for the test."
  (let ((remote1  (file-remote-p file1))
        (remote2  (file-remote-p file2)))
    (and (equal remote1 remote2)  (file-equal-p file1 file2))))