create-scratch-buffer.el

(defmacro create-scratch-buffer (name &optional comment body)
  "Create a new custom scratch buffer. The name should be a valid major mode name without -mode suffix.
The body should be lambda block or a symbol of function that be invoked after a scratch buffer created. nil is accepted to turn it off."
  `(defun ,(intern (concat "scratch-" name))
       ()
     (interactive)
     (let ((bufname (concat "*scratch-" ,name "*")))
       (if (buffer-live-p (get-buffer bufname))
           (switch-to-buffer bufname)
         (with-current-buffer (get-buffer-create bufname)
           (setq buffer-read-only nil)
           (when ,comment
             (insert-string (concat ,comment "\n\n")))
           (,(intern (concat name "-mode")))
           (when ,body
             (funcall ,body))
           (delete-other-windows)
           (switch-to-buffer bufname))))))


;;; Examples

;; scratch-sql
;; C-c C-c to send a last line to *SQL* buffer.
(setenv "MYSQL_PS1" "")
(create-scratch-buffer
 "sql"
 "-- This buffer is for notes you don't want to save, and for SQL evaluation.
-- If you want to create a file, visit that file with C-x C-f,
-- then enter the text in that file's own buffer."
 '(lambda ()
    (sql-product-interactive
     (completing-read
      "Product: "
      '(ansi db2 informix ingres interbase linter microsoft mysql oracle postgres solid sqlite sybase)))))

;; scratch-lisp
(setq inferior-lisp-program "clisp")
(create-scratch-buffer
 "lisp"
 ";; This buffer is for notes you don't want to save, and for Common Lisp evaluation.
;; If you want to create a file, visit that file with C-x C-f,
;; then enter the text in that file's own buffer."
 #'slime)