Run blocks of code in python interpreter using keybinding

run_block.el

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;; Highlight blocks and send to Python interpreter

(defun search-unique (marker)
  "Search for the first and only occurrence of MARKER.
Return the position if found, or nil if not found or multiple occurrences exist."
  (let ((first-pos nil)
        (count 0))
    (save-excursion
      (goto-char (point-min))
      (while (search-forward marker nil t)
        (setq count (1+ count))
        (when (= count 1)
          (setq first-pos (point)))))
    (if (= count 1)
        first-pos
      nil)))

(defun highlight-block (start-marker stop-marker)
  "Set the region between START-MARKER and STOP-MARKER, activate the mark,
and return the region boundaries as a cons cell (start . end)."
  (interactive "sStart marker: \nsStop marker: ")
  (let ((start-pos (save-excursion
                     (when-let ((pos (search-unique start-marker)))
                       (goto-char pos)
                       (beginning-of-line)
                       (point))))
        (end-pos (save-excursion
                   (when-let ((pos (search-unique stop-marker)))
                     (goto-char pos)
                     (end-of-line)
                     (point)))))
    (when (and start-pos end-pos)
      (push-mark start-pos)
      (goto-char end-pos)
      (activate-mark)
      (cons start-pos end-pos))))


(defun python-run-block (start-marker end-marker)
  "Highlight the block between START-MARKER and END-MARKER and send it to the Python shell."
  (interactive "sStart marker: \nsEnd marker: ")
  (let ((current-pos (point))
        (region (highlight-block start-marker end-marker)))  ; Save the current cursor position
    (if region
        (let ((start (car region))
              (end (cdr region)))
          (message "Region is set: %s to %s" start end)  ; Debugging message
          (python-shell-send-region start end)
          (deactivate-mark)  ; Deactivate the mark to remove highlighting
          (message "Sent region to Python shell"))
      (message "No region set"))
    (goto-char current-pos)))  ; Restore the cursor position

;; Define keybindings for different blocks
;;
;; Ex:
;;   # START_BLOCK_1
;;   print('hi')
;;   # END_BLOCK_1
;; C-c 1  ; run that block
(dolist (i (number-sequence 1 5))
  (define-key python-mode-map
    (kbd (format "C-c %d" i))
    `(lambda ()
       (interactive)
       (python-run-block
        ,(format "START_BLOCK_%d" i)
        ,(format "END_BLOCK_%d" i)))))

Example: https://x.com/neurallambda/status/1797040531182330087