elisp python-on-region

python-on-region.el

(defvar
  python-on-region-template
  "#! /usr/bin/env python3\nimport sys\nfor line in sys.stdin:\n    sys.stdout.write(line$$)\n"
  "The template to use for python-on-region. $$ indicates the point.")

(defun python-on-region--run ()
  (interactive)
  (save-buffer)
  (delete-window)
  (switch-to-buffer python-on-region--buffer)
  (chmod python-on-region--file (logior (file-modes python-on-region--file) #o111))
  (if (region-active-p)
    (shell-command-on-region (region-beginning) (region-end) python-on-region--file (current-buffer) 'no-mark)
    (shell-command-on-region 0 -1 python-on-region--file (current-buffer) 'no-mark)))

(defun python-on-region ()
  "Run a python script on the current region."
  (interactive)
  (setq python-on-region--buffer (current-buffer))
  (setq python-on-region--file (make-temp-file "" nil ".py" python-on-region-template))

  (split-window-sensibly)
  (other-window 1)
  (find-file python-on-region--file)
  (local-set-key (kbd "C-c C-c") 'python-on-region--run)
  (replace-string "$$" ""))