Nothing, of course. I just find the macros that give you a "modified environment" to run some code short and sweet. with-temp-buffer is another example: a macr

Nothing, of course. I just find the macros that give you a "modified environment" to run some code short and sweet. with-temp-buffer is another example: a macro that bridges the functions for "string manipulation" and the ones for "buffer manipulation", since you start writing stuff this way: (defun replace-in-string (str from to) (with-temp-buffer (insert str) (beginning-of-file) ;;; Here you can use all your normal text editing commands (replace-regexp from to nil t) (buffer-string))) Lots of dirty manipulation, but from outside its a pure function, and doesn't change the editor state in any way after it runs.