On Fri, 12 Apr 2002  16:22:57 +0900, Hal E. Fulton wrote:
[snip]
> > I know the problem you want to solve.  I'm considering something like
> > CLOS's method combination, or Emacs's defadvice for the matter.
> 
> OK, I am glad it is a sensible idea...
> 
> I know nothing of CLOS or of this defadvice thing, however.
> 
> If anyone wishes to enlighten me, I would like to learn.

defadvice is Aspect Oriented Programming, like aspectr (RAA). What you
described is the before-part of an advice function (or aspect, if you
will)

From advice.el:

;; @ Introduction:
;; ===============
;; This package implements a full-fledged Lisp-style advice mechanism
;; for Emacs Lisp. Advice is a clean and efficient way to modify the 
;; behavior of Emacs Lisp functions without having to keep  personal
;; modified copies of such functions around. A great number of such 
;; modifications can be achieved by treating the original function as a 
;; black box and specifying a different execution environment for it 
;; with a piece of advice. Think of a piece of advice as a kind of fancy
;; hook that you can attach to any function/macro/subr.

;; @ Highlights:
;; =============
;; - Clean definition of multiple, named before/around/after advices
;;   for functions, macros, subrs and special forms
;; - Full control over the arguments an advised function will receive,
;;   the binding environment in which it will be executed, as well as the
;;   value it will return.
;; - Allows re/definition of interactive behavior for functions and subrs
;; - Every piece of advice can have its documentation string which will be 
;;   combined with the original documentation of the advised function at
;;   call-time of `documentation' for proper command-key substitution.
;; - The execution of every piece of advice can be protected against error
;;   and non-local exits in preceding code or advices.
;; - Simple argument access either by name, or, more portable but as
;;   efficient, via access macros
;; - Allows the specification of a different argument list for the advised
;;   version of a function.
;; - Advised functions can be byte-compiled either at file-compile time
;;   (see preactivation) or activation time.
;; - Separation of advice definition and activation
;; - Forward advice is possible, that is
;;   as yet undefined or autoload functions can be advised without having to
;;   preload the file in which they are defined. 
;; - Forward redefinition is possible because around advice can be used to
;;   completely redefine a function.
;; - A caching mechanism for advised definition provides for cheap deactivation
;;   and reactivation of advised functions.
;; - Preactivation allows efficient construction and compilation of advised
;;   definitions at file compile time without giving up the flexibility of
;;   the advice mechanism.
;; - En/disablement mechanism allows the use of  different "views" of advised
;;   functions depending on what pieces of advice are currently en/disabled
;; - Provides manipulation mechanisms for sets of advised functions via 
;;   regular expressions that match advice names


regards,
Michel