From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: ludo@gnu.org (Ludovic =?iso-8859-1?Q?Court=E8s?=) Newsgroups: gmane.lisp.guile.user Subject: Re: Getting a type of a variable Date: Sun, 20 Jul 2008 22:48:42 +0200 Message-ID: <87abgcl1sl.fsf@gnu.org> References: NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1216586959 17042 80.91.229.12 (20 Jul 2008 20:49:19 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 20 Jul 2008 20:49:19 +0000 (UTC) To: guile-user@gnu.org Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Sun Jul 20 22:50:08 2008 Return-path: Envelope-to: guile-user@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1KKfqr-0005hy-Ud for guile-user@m.gmane.org; Sun, 20 Jul 2008 22:49:54 +0200 Original-Received: from localhost ([127.0.0.1]:37242 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KKfpy-00056B-SQ for guile-user@m.gmane.org; Sun, 20 Jul 2008 16:48:58 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KKfpu-00055e-8W for guile-user@gnu.org; Sun, 20 Jul 2008 16:48:54 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KKfps-00055G-IF for guile-user@gnu.org; Sun, 20 Jul 2008 16:48:53 -0400 Original-Received: from [199.232.76.173] (port=59853 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KKfps-00055C-FN for guile-user@gnu.org; Sun, 20 Jul 2008 16:48:52 -0400 Original-Received: from main.gmane.org ([80.91.229.2]:45228 helo=ciao.gmane.org) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1KKfps-00018g-5B for guile-user@gnu.org; Sun, 20 Jul 2008 16:48:52 -0400 Original-Received: from list by ciao.gmane.org with local (Exim 4.43) id 1KKfpq-0003qD-0k for guile-user@gnu.org; Sun, 20 Jul 2008 20:48:50 +0000 Original-Received: from reverse-83.fdn.fr ([80.67.176.83]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 20 Jul 2008 20:48:50 +0000 Original-Received: from ludo by reverse-83.fdn.fr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 20 Jul 2008 20:48:50 +0000 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 22 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: reverse-83.fdn.fr X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 3 Thermidor an 216 de la =?iso-8859-1?Q?R=E9volution?= X-PGP-Key-ID: 0xEA52ECF4 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 821D 815D 902A 7EAB 5CEE D120 7FBA 3D4F EB1F 5364 X-OS: i686-pc-linux-gnu User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) Cancel-Lock: sha1:A78duoHNf4T4jec+xN8zgMXK5Kk= X-detected-kernel: by monty-python.gnu.org: Linux 2.6, seldom 2.4 (older, 4) X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-user-bounces+guile-user=m.gmane.org@gnu.org Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.user:6683 Archived-At: Hello, "Maciek Godek" writes: > The solution of my dreams is that it would turn out > that there's a function defined in the scm api: > scm_t_bits scm_get_type(SCM *var) > that returns a type tag and that there's a way to decipher > the contents of this return value, and that it is wisely > defined for all builtin types. If you are to dive into such low-level things, you could implement in Scheme type tag "deciphering". You'd use the `object-address' procedure, and then re-implement type tag encoding/decoding from "libguile/tags.h" at the Scheme level. That'd be an interesting exercise as the Scheme implementation would be readily understandable (compared to obscure C macros and informal comments). Otherwise, Andy's suggestion may be wiser. ;-) Thanks, Ludovic.