From: pjb@informatimago.com (Pascal J. Bourguignon)
To: help-gnu-emacs@gnu.org
Subject: Re: What is the best way to navigate #ifdef and #endif in C program
Date: Fri, 06 Aug 2010 01:46:26 +0200 [thread overview]
Message-ID: <87zkx0vd0t.fsf@kuiper.lan.informatimago.com> (raw)
In-Reply-To: i3f9co$gss$1@news.eternal-september.org
Peter Keller <psilord@cs.wisc.edu> writes:
> In comp.lang.lisp Elena <egarrulo@gmail.com> wrote:
>> On 4 Ago, 17:09, Peter Keller <psil...@cs.wisc.edu> wrote:
>>> Specifically:http://letoverlambda.com/index.cl/guest/chap5.html#sec_4
>>>
>>> Would show you how to write a macro such that it adds Scheme's tail call
>>> optimized "named let" into Common Lisp. ?This goes beyond the concept
>>> of syntactic sugar and enters the domain of pure code transformation.
>>
>> Indeed, code transformation is what sets CL's macros apart. However,
>> TCO is much more than that. Read here:
>>
>> http://stackoverflow.com/questions/2181852/tail-call-elimination-in-clojure
>
> After reading that, I assert that I don't know how to take base CL
> and make it tail recursive since redefining things like defun and
> whatnot lead to package lock errors. Even things like define-compiler-macro
> can't redefine any of the CL macros or functions.
>
> One probably could have success if they created forms like defun-tco,
> labels-tco, flet-tco, etc which kept track of their code expansions
> and rewrote them to be tco. But at that point you've implemented a
> tco enforced lisp dialect on top of CL.
It is almost trivial to provide a package (possibly even named
"COMMON-LISP") which is like the "COMMON-LISP" package, but that is
not the implementation's "COMMON-LISP" package.
See for example:
http://www.informatimago.com/develop/lisp/small-cl-pgms/ibcl/
The trick is in defining a defpackage form such as:
(defmacro defpackage (name &rest options)
`(cl:defpackage ,name
,@(mapcar
(lambda (option)
(if (listp option)
(case (first option)
((:use)
(substitute "IBCL" "COMMON-LISP"
(substitute "IBCL" "CL" option)))
((:shadowing-import-from :import-from)
(if (member (string (second option))
'("CL" "COMMON-LISP")
:test (function string=))
(list* (first option)
"IBCL"
(cddr option))
option))
(otherwise option))))
options)))
where you substitute the "COMMON-LISP" package for your own. (You
also need to define your own reader and loader, but these components
are available too).
--
__Pascal Bourguignon__ http://www.informatimago.com/
next prev parent reply other threads:[~2010-08-05 23:46 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-03 0:31 What is the best way to navigate #ifdef and #endif in C program Daniel (Youngwhan)
2010-08-04 4:45 ` [OT] " Fren Zeee
2010-08-04 10:27 ` Pascal J. Bourguignon
2010-08-04 10:38 ` Alessio Stalla
2010-08-04 11:57 ` Pascal J. Bourguignon
2010-08-04 14:37 ` Elena
2010-08-04 14:59 ` Arzobispo Andante
2010-08-04 15:09 ` Peter Keller
2010-08-04 15:35 ` Peter Keller
2010-08-05 19:04 ` Elena
2010-08-05 21:10 ` Peter Keller
2010-08-05 23:46 ` Pascal J. Bourguignon [this message]
[not found] ` <8c27aoFij2U1@mid.individual.net>
2010-08-06 11:17 ` Elena
2010-08-06 13:55 ` Pascal J. Bourguignon
2010-08-04 16:20 ` Elena
2010-08-04 16:23 ` Elena
2010-08-05 18:00 ` Emmy Noether
2010-08-06 4:59 ` [OT] " Aaron W. Hsu
2010-08-05 17:30 ` Johan Bockgård
2010-08-06 17:03 ` Alan Mackenzie
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87zkx0vd0t.fsf@kuiper.lan.informatimago.com \
--to=pjb@informatimago.com \
--cc=help-gnu-emacs@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.