nadvice

This package lets you add behavior (which we call "piece of advice") to
existing functions, like the old `advice.el' package, but with much fewer
bells and whistles.  It comes in 2 parts:

- The first part lets you add/remove functions, similarly to
  add/remove-hook, from any "place" (i.e. as accepted by `setf') that
  holds a function.
  This part provides mainly 2 macros: `add-function' and `remove-function'.

- The second part provides `advice-add' and `advice-remove' which are
  refined version of the previous macros specially tailored for the case
  where the place that we want to modify is a `symbol-function'.