From: "Maciek Godek" <pstrychuj@gmail.com>
To: "Kjetil S. Matheussen" <k.s.matheussen@notam02.no>
Cc: guile-user@gnu.org
Subject: Re: References/locations
Date: Fri, 15 Aug 2008 12:14:05 +0200 [thread overview]
Message-ID: <e2ceda030808150314s1be777b5qea6a6923d406e00c@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0808082021001.5443@ttleush>
Kjetil:
> Well, here's a relatively clean way, I think:
>
> (define-macro (location name)
> (define new-val (gensym))
> `(lambda (,new-val)
> (set! ,name ,new-val)))
>
> (define old-set! set!)
>
> (define-macro (set! a b)
> `(if (procedure? ,a) ;; Needs a better check.
> (,a ,b)
> (old-set! ,a ,b)))
>
>
> guile> (define x 10)
> guile> (define y (location x))
> guile> (set! y 20)
> guile> x
> 20
> guile>
I just realized that this is only a partial solution.
Continuing the above example,
guile> y
#<procedure #f (#syntmp-\ g1336-76}#)>
I don't know how to solve it: the problem is that
you actually can't bind a function call to a variable.
But even without it, the line
(define old-set! set!)
breaks:
ERROR: invalid syntax set!
I've been thinking of implementing this "location" stuff
as a smob, but you've got the point that it is (probably)
impossible to implement the location system without
redefining set! and define.
Regards
M.
next prev parent reply other threads:[~2008-08-15 10:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cmu-lmtpd-5833-1218211546-4@mail-imap1.uio.no>
2008-08-08 18:34 ` References/locations Kjetil S. Matheussen
2008-08-10 23:00 ` References/locations Maciek Godek
2008-08-15 10:14 ` Maciek Godek [this message]
2008-08-15 13:55 ` References/locations Clinton Ebadi
2008-08-18 8:09 ` References/locations Maciek Godek
2008-08-18 16:15 ` References/locations Clinton Ebadi
2008-08-08 1:50 References/locations Maciek Godek
2008-08-10 7:51 ` References/locations Stephen Compall
2008-08-15 9:35 ` References/locations Maciek Godek
[not found] ` <e2ceda030808141732r524fc0cehb8ae7c6007550ea6@mail.gmail.com>
[not found] ` <m2wsihltfv.fsf@member.fsf.org>
[not found] ` <e2ceda030808200441q52d9858bv63323055e0f6308a@mail.gmail.com>
2008-08-21 5:05 ` References/locations Stephen Compall
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