You'll be wanting to look at defadvice in Common Lisp and elisp, then, which let you attach code to the entry and exit of a function. Python has decorators, as

You'll be wanting to look at defadvice in Common Lisp and elisp, then, which let you attach code to the entry and exit of a function. Python has decorators, as well, which are similar, but the entire purpose of defadvice is to do exactly what you're talking about.