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From: Neil Jerram <neil@ossau.uklinux.net>
Cc: tomas@fabula.de, guile-devel@gnu.org
Subject: Re: memoization and error messages
Date: 28 Nov 2002 19:34:11 +0000	[thread overview]
Message-ID: <m3ptspsd3g.fsf@laruns.ossau.uklinux.net> (raw)
In-Reply-To: <Pine.GSO.4.05.10211241703440.28618-100000@sallust.ida.ing.tu-bs.de>

>>>>> "Dirk" == Dirk Herrmann <dirk@sallust.ida.ing.tu-bs.de> writes:

    Dirk> On Sun, 24 Nov 2002 tomas@fabula.de wrote:
    >> That means that macros aren't anymore `first class objects'? What
    >> consequences does this have for meta-programming?

    Dirk> I don't know.  Can you be a little more specific about what you want to
    Dirk> accomplish that you can only accomplish with macros as first-class objects
    Dirk> (or rather said "accomplish cleanly")?  If so, please provide code
    Dirk> examples that show your approaches.

What about the uses of `macro?' in `fset' in
lang/elisp/internals/fset.scm - how does this code look with your
changes?  (My understanding is that it is no longer possible to pass
around a macro value in a variable - please correct me if that's wrong.)

    Dirk> [rambling on]
    Dirk> It may make sense to point out the following:  Separate in-advance
    Dirk> memoization brings the possibility to speed up evaluation, it allows to
    Dirk> store pre-compiled code and thus speed up loading time, and it is a great
    Dirk> way to clean up guile's internals and achieve better R5RS conformance.

Agreed, and it paves the way for various kinds of fuller compilation.

    Dirk> But, for those who depend on dynamic code expansion (i. e. re-expansion of
    Dirk> code whenever a macro changes) there is always eval.

I think you are probably right that eval is the way forward, so I'll
try to learn to like it :-)  However, I wonder if dynamic expansion
usages actually need local-eval rather than R5RS eval - which is
tricky because local-eval is in a grey area at the moment.
(i.e. Marius called it a `weird critter' :-)

To test this, I offer a challenge (to anyone, not just Dirk): given
define-macro (or defmacro) behaving as Dirk proposes, write a
define-non-memoizing-macro macro that can be used to define a macro
that is expanded every time its containing expression is evaluated.

        Neil



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      parent reply	other threads:[~2002-11-28 19:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-11-24 10:43 memoization and error messages Dirk Herrmann
2002-11-24 12:57 ` tomas
2002-11-24 16:49   ` Dirk Herrmann
2002-11-24 22:25     ` Daniel Skarda
2002-11-28 18:02       ` Dirk Herrmann
2002-12-02 20:45         ` Daniel Skarda
2002-12-03  0:09           ` Lynn Winebarger
2002-11-26 10:42     ` tomas
2002-11-28 19:34     ` Neil Jerram [this message]

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