From: Stefan Israelsson Tampe <stefan.itampe@gmail.com>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: guile-devel@gnu.org
Subject: Re: Enhancement to the syntax system?
Date: Tue, 3 Jul 2012 23:52:29 +0200 [thread overview]
Message-ID: <CAGua6m38DUYmntqwOvF+ZFGA7_c_=Mh8dpmzKBj-pp1Mk=F70A@mail.gmail.com> (raw)
In-Reply-To: <878vf0o7gs.fsf@gnu.org>
[-- Attachment #1: Type: text/plain, Size: 1291 bytes --]
You do not need gensyms if you try to mimic or implement my suggested #. .
On the
other hand when if you do this
(define (f stx) #`(let ((x 1)) #,stx))
and use this with
#`(let ((x 2)) #,(f #'x))
the resulting expanded code would produce 1 which is not what you want.
So in the racket matcher I wrote I needed to do
(with-syntax ((x (datum->syntax stx (gensym "x")))) #`(let ((x 2)) #,(f
#'x))))))
Hope that this makes things clear!
/Stefan
On Tue, Jul 3, 2012 at 11:33 PM, Ludovic Courtès <ludo@gnu.org> wrote:
> Hey!
>
> Stefan Israelsson Tampe <stefan.itampe@gmail.com> skribis:
>
> >> Stefan Israelsson Tampe <stefan.itampe@gmail.com> skribis:
> >>
> >> > Maybe this help to see what I'm after,
> >> >
> >> > #'(let ((x v)) #.(f #'x))
> >> >
> >> > <=>
> >> >
> >> > (let-syntax ((g (lambda (stx) (syntax-case stx ((_ x) (f #'x)))))
> >> > #'(let ((x v)) (g x))
>
> [...]
>
> > If you want to try another path using functions in stead of macros and
> > working hard with #, and #,@
> > you will for complex macros like a matcher need to gensym by hand or
> > destroy the readability of the
> > code. As illustrated by the simple example above.
>
> Hmm, the example above does not use gensym. What am I missing?
>
> Ludo’.
>
[-- Attachment #2: Type: text/html, Size: 1910 bytes --]
next prev parent reply other threads:[~2012-07-03 21:52 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-30 15:22 Enhancement to the syntax system? Stefan Israelsson Tampe
2012-07-02 19:28 ` Ludovic Courtès
2012-07-02 20:43 ` Stefan Israelsson Tampe
2012-07-02 22:41 ` Ludovic Courtès
2012-07-03 14:37 ` Stefan Israelsson Tampe
2012-07-03 21:33 ` Ludovic Courtès
2012-07-03 21:52 ` Stefan Israelsson Tampe [this message]
2012-07-04 7:47 ` Marijn
2012-07-04 8:04 ` Stefan Israelsson Tampe
2012-07-09 15:52 ` Ludovic Courtès
2012-07-09 17:40 ` Stefan Israelsson Tampe
2012-07-10 8:24 ` Ludovic Courtès
2012-07-10 13:35 ` Stefan Israelsson Tampe
2012-07-10 14:34 ` Marijn
2012-07-10 14:51 ` [racket-dev] " Eli Barzilay
[not found] ` <20476.16781.257276.194149-a5nvgYPMCZcx/1z6v04GWfZ8FUJU4vz8@public.gmane.org>
2012-07-10 15:03 ` Matthew Flatt
2012-07-10 15:26 ` [racket-dev] " Ludovic Courtès
2012-07-10 15:44 ` Stefan Israelsson Tampe
2012-07-10 17:47 ` Stefan Israelsson Tampe
2012-07-10 16:48 ` Eli Barzilay
2014-05-03 21:29 ` Marijn Schouten (hkBst)
2012-07-10 15:44 ` Ryan Culpepper
2012-07-10 15:22 ` Ludovic Courtès
2012-07-10 7:36 ` Stefan Israelsson Tampe
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
List information: https://www.gnu.org/software/guile/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAGua6m38DUYmntqwOvF+ZFGA7_c_=Mh8dpmzKBj-pp1Mk=F70A@mail.gmail.com' \
--to=stefan.itampe@gmail.com \
--cc=guile-devel@gnu.org \
--cc=ludo@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.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).