elisp code for interactive programming in python

repl.el

  (defvar python-shell-send-code-step-on-function nil
    "If non-nil, step sending a function to the python interpreter.")

  (defun python-shell-step-after-defun ()
    (forward-paragraph)
    ;; when at last paragraph, don't step to beginning of "next" paragraph
    (unless (equal (line-number-at-pos (point))
                   (progn (forward-paragraph) (line-number-at-pos (point))))
      (backward-paragraph)
      (forward-line 1)))

  (defun python-shell-send-paragraph-and-step ()
    "Send current paragraph of code and move point to the beginning of next paragraph."
    (interactive)
    (save-excursion
      (let* ((beg (progn (forward-paragraph)
                         (backward-paragraph)
                         (unless (equal (line-number-at-pos) 1) 
                           (forward-line)) (point)))
             (end (progn (forward-paragraph) 
                         (unless (equal (line-number-at-pos (point))
                                        (line-number-at-pos (point-max)))
                           (forward-line -1))
                         (end-of-line)
                         (point)))
             (num-lines (1+ (- (line-number-at-pos end)
                               (line-number-at-pos beg)))))
        (python-shell-send-region beg end)
        (message (concat 
                  (format "Sent %d line%s "
                          num-lines
                          (if (equal num-lines 1) "" "s"))
                  (if (equal num-lines 1) 
                      (format "(line %d)" (line-number-at-pos end))
                    (format "(lines %d-%d)" 
                            (line-number-at-pos beg) 
                            (line-number-at-pos end)))
                  " to Python interpreter")
                 (line-number-at-pos beg)
                 (line-number-at-pos end))))
    (python-shell-step-after-defun))

  (defun python-current-defun ()
    "`python-info-current-defun' doesn't work when on a blank line, for some reason."
    (interactive)
    (save-excursion (forward-paragraph)
                    (backward-paragraph)
                    (forward-line)
                    (python-info-current-defun)))

  (defun python-shell-send-code-and-step (arg)
    "Send code at point dwim-style. With prefix arg, step afterwards to next chunk of code."
    (interactive "p")
    ;; xemacs doesn't have use-region-p
    (let ((python-shell-send-code-step-on-function
           (if (equal arg 4) t nil)))
      (unless (python-shell-get-process)
        (run-python))
      (cond ((use-region-p)
             (let ((end (region-end))
                   (beg (region-beginning)))
               (python-shell-send-region beg end)
               (message "Sent region between lines %d and %d to python interpreter"
                        (line-number-at-pos beg)
                        (line-number-at-pos end))
               (goto-char end)))
            ;; send function if in a function, else send block and iterate
            ((python-current-defun)
             (progn
               (python-shell-send-defun)
               (message "Sent '%s' function to python interpreter"
                        (propertize (python-current-defun) 'face
                                    '(:foreground "#66D9EF")))
               (when python-shell-send-code-step-on-function
                 (python-nav-end-of-defun)
                 (forward-line -1)
                 (python-shell-step-after-defun))))
            (t
             (python-shell-send-paragraph-and-step)))))