Override functionality needs to be completed

These aspects of the override functionality need to be completed:

 * Ability to specify how the given function is overridden.
   * Replace the original version.
   * Wrap the original version.
   * Chained before the original version.
   * Chained after the original version.
 * Complete the functionality to inject an override.
 * Complete the functionality to remove an override.

Other aspects:

 * Solid error handling.
   * Should be possible to place overrides and wrap them for
     error handling.  Perhaps with the option to restore the
     original version if an override errors, or to remove
     just that override whether it restores the original version
     or leaves a sequence of others.
   * If the error handling is there to ensure the override works
     it might be removal after the first call.  Although perhaps
     it is better that it remains permanently.
 * Duration.
   * An override might be present for N calls.
   * An override might be present for a period of time.

Original issue reported on code.google.com by richard.m.tew@gmail.com on 28 Dec 2006 at 4:27

fritzo / livecoding

Override functionality needs to be completed #2