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* Closure?
@ 2008-07-11 14:48 Maciek Godek
  2008-07-11 15:01 ` Closure? Ludovic Courtès
  2008-07-12 22:57 ` Closure? Neil Jerram
  0 siblings, 2 replies; 20+ messages in thread
From: Maciek Godek @ 2008-07-11 14:48 UTC (permalink / raw)
  To: guile-user

Hi folks,

I've been wondering if there's any way to recall
(or get inside) an environment of a closure (= to
directly access variables bound to a closure)

And here's what I mean exactly:

(define ++ (let ((c 0)) (lambda()(set! c (1+ c))c)))
; we now have a closure
(procedure-environment ++)
;-> ((c . 0) #<eval-closure 7f6d672efa80>)
(++)
;-> 1
; Now I would like to be able to do the following:
(with (procedure-environment ++) (set! c 20))
; the c variable in closure ++ is set to 20
(define -- (with (procedure-environment ++)
        (lambda()(set! c (1- c)) c)))

; here we have a new function bound to the same closure
(--)
;-> 19

Is there any way to achieve this in guile?
(it is especially important for me to make it
efficiently doable from C). I've tried some
funny combinations of eval and procedure-environment,
but they didn't work out.

Additionaly, it would be nice to see the possibility
of explicit definitions of environments, like:

(define env (make-closure (a . 1)(b . 2))
(with env (define c 3))

so that we could define the aforementioned
counter as:
(define counter-env (make-closure (c . 0)))
(define ++ (with counter-env (lambda()(set! c (1+ c))c)))
and so forth.

By the way, the let special form could then be
defined using this make-environment function
(define-macro (let bindings body)
  (with (make-closure* bindings) body))

(I've suffixed the name with asterisk as some
transformations between the let bindings and
make-closure bindings are required to make it
work properly)

Hope I'm not reinventing the wheel here; it
would be nice to be able to use guile in such
way, though (and to make sure that it is
efficient from the C level as well). It
would also make scheme oop more intuitive,
as method names could be hidden inside a closure
and so it would allow the following syntax:

(with object (method args))

which corresponds to the famous dot syntax
known from many oo-languages like c++ or python:

object.method(args)

Would it be difficult to implement such
functionality in guile? (if there's none implemented yet
-- I didn't find anything in the documentation)

tia4i
(thanks in advance for implementation :)
Maciek Godek




^ permalink raw reply	[flat|nested] 20+ messages in thread
[parent not found: <cmu-lmtpd-26382-1215792454-10@mail-imap1.uio.no>]
[parent not found: <cmu-lmtpd-15105-1216051603-3@mail-imap1.uio.no>]

end of thread, other threads:[~2008-07-16 16:42 UTC | newest]

Thread overview: 20+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-07-11 14:48 Closure? Maciek Godek
2008-07-11 15:01 ` Closure? Ludovic Courtès
2008-07-11 15:32   ` Closure? Maciek Godek
2008-07-12 22:57 ` Closure? Neil Jerram
2008-07-13  6:57   ` Closure? Maciek Godek
2008-07-13 22:56     ` Closure? Neil Jerram
2008-07-14  1:15       ` Closure? Maciek Godek
     [not found] <cmu-lmtpd-26382-1215792454-10@mail-imap1.uio.no>
2008-07-11 17:42 ` Closure? Kjetil S. Matheussen
2008-07-11 17:47   ` Closure? Kjetil S. Matheussen
2008-07-11 20:54     ` Closure? Maciek Godek
2008-07-12 11:47       ` Closure? Kjetil S. Matheussen
2008-07-13  6:59         ` Closure? Maciek Godek
2008-07-12 22:43     ` Closure? Neil Jerram
2008-07-15  7:59       ` Closure? Ludovic Courtès
2008-07-15  9:11         ` Closure? Andy Wingo
2008-07-16 16:42           ` Closure? Ludovic Courtès
     [not found] <cmu-lmtpd-15105-1216051603-3@mail-imap1.uio.no>
2008-07-14 16:30 ` Closure? Kjetil S. Matheussen
2008-07-14 21:14   ` Closure? Maciek Godek
     [not found]   ` <e2ceda030807141414i5acef7d1h37d12d14e01cc1d@mail.gmail.com>
2008-07-14 21:41     ` Closure? Kjetil S. Matheussen
2008-07-14 22:46       ` Closure? Maciek Godek

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