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From: quiroz@cs.rochester.edu (Cesar Quiroz)
Newsgroups: comp.emacs
Subject: Re: hooks in Gnumacs
Message-ID: <2445@sol.ARPA>
Date: Sun, 20-Sep-87 17:48:38 EDT
Article-I.D.: sol.2445
Posted: Sun Sep 20 17:48:38 1987
Date-Received: Sun, 20-Sep-87 23:36:14 EDT
References: <280@hrc63.co.uk> <28500017@ccvaxa>
Reply-To: quiroz@ROCHESTER.UUCP (Cesar Quiroz)
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 26
Keywords: advice flavors hooks O-O
Summary: Generalized user-defined hooks = advise facilities | O-O methods

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From article <28500017@ccvaxa> (aglew@ccvaxa.UUCP):
: ... instead of every package using a slightly different name for
:its pre and post hooks, have no hooks at all, but let the user be
:able to add them dynamically, in a standard way.
Looks like a useful idea.  Other Lisps (Interlisp, for one) have
well evolved `advising' facilities, that permit not only pre- and
post- customized activity, but also around- activity.  The user
retains ultimate control and can do useful things not thought of by
the original writer.

For instance, take the old newline-and-reindent (or whatever it was
called).  It could have been just an around-advice of indent-line,
that called the internal function twice.  (Details might be a little
out of synch with reality, please just get the big picture.)
Byrne's code could be used as a starting point.  (Getting the advice
to the right place is a simple macro, controlling how different
pieces of advice interact takes a bit more effort, storing and
retrieving the advice might be harder...  Hmm, going beyond the
simple seems to require something like flavor composition.)


-- 
Cesar Augusto  Quiroz Gonzalez
Department of Computer Science     {allegra|seismo}!rochester!quiroz
University of Rochester            or
Rochester,  NY 14627               quiroz@cs.rochester.edu