Table of Contents

Writing an emacs lisp command

(defun transpose-windows ()
 "transpose current-window and next-window"
 (setq buffer-1 (buffer-name))
 (message "jumping to other window")
 (setq buffer-2 (buffer-name))       
 (switch-to-buffer (buffer-1))
 (other-window -1)
 (switch-to-buffer (buffer-2)))
(setq cur-buffer (buffer-name))

writing commands incrementally

Emacs has many great features to help yoy write functions. For instance you can evaluate functions and variable write in the emacs editing buffer by typing:

C-x C-e

after the variable name or after the closing parenthesis of a function. And the results will be echoed in the mini-buffer.

For instance you could type the following into a buffer, and then type C-x C-e after, to evaluate.

  • Next Incremental Step
    Start with a simple command to save the current buffer's name in a variable and then jump to other window and write both that variable and the current buffer's name ```cl (defun jmp-print-buffer () "jump to next-window and swap to current buffer" (interactive) (setq buffer1 (buffer-name)) (message "buffer1 is %s" buffer1) (other-window 1) (message "buffer1 was %s" buffer1) (message "buffer-name is %s" buffer-name)) ```

    Next, write a function to save buffer name, jump to other-window and switch buffers to that buffer.

    ```cl (defun jmp-swap () "jump to next-window and swap to current buffer" (interactive) (setq buffer-1 (buffer-name)) (message "buffer-1 is %s" buffer-1) (other-window -1) (switch-to-buffer buffer-1) (message "buffer-1 is %s" buffer-1) (message "buffer-name is %s" buffer-name)) ```

This works!!

Now, its time to finish the program!


(defun transpose-windows () 
 "Swap buffer in current window with next window."
 (setq buffer1 (buffer-name))
 (other-window 1)
 (setq buffer2 (buffer-name))
 ;;(message "current buffer was %s" buffer1)
 ;;(message "current buffer now: %s" (buffer-name))
 ;;(message "oh yes! will switch to %s" buffer2)
 (switch-to-buffer buffer1)
 (other-window -1)
 (switch-to-buffer buffer2))