From: "Pascal J. Bourguignon" <pjb@informatimago.com>
To: help-gnu-emacs@gnu.org
Subject: Re: plists, alists, and hashtables
Date: Thu, 06 Aug 2015 22:00:34 +0200 [thread overview]
Message-ID: <87lhdombkt.fsf@kuiper.lan.informatimago.com> (raw)
In-Reply-To: mailman.7890.1438888393.904.help-gnu-emacs@gnu.org
Stefan Monnier <monnier@iro.umontreal.ca> writes:
> More specifically, I highly doubt that a special «k1 v1 k2 v2 ...»
> syntax for hash-tables would make much difference compared to
> (hash-table k1 v1 k2 v2 ...) which you can get today with a very simple
> `hash-table' macro. I mean, you'd still have to say (gethash k m),
> whereas you'd probably want something like m.k, etc...
> For better or for worse, Elisp is not Python.
I would like that while elisp lacks reader macros, you can still do a
lot of things (with a pinch of kludgery) with macros.
For example, you could write something like:
(with-my-syntax
(let ((h «k1 v1 k2 v2 k3 v3»))
h.k4:=44
print (list h.k1 h.k2)))
Notice that the lisp reader will read as symbols things that you'd wish
to be separate tokens:
(flatten '(with-my-syntax
(let ((h «k1 v1 k2 v2 k3 v3»))
h.k4:=44
print (list h.k1 h.k2))))
--> (with-my-syntax let h «k1 v1 k2 v2 k3 v3» h\.k4:=44 print list h\.k1
h\.k2)
Nonethelss, your with-my-syntax macro can parse those symbols, and
reconstitute a normal sexp:
(macroexpand ' (with-my-syntax
(let ((h «k1 v1 k2 v2 k3 v3»))
h.k4:=44
print (list h.k1 h.k2))))
--> (let ((h (hash-table 'k1 'v1 'k2 'v2 'k3 'v3)))
(setf (gethash 'k4 h) 44)
(print (list (gethash 'k1 h) (gethash 'k2 h))))
So you can still be happy.
The only constraint is that you cannot have an unbalanced sexp in the
body of your macro (parentheses, double-quote strings, vector brackets,
etc).
--
__Pascal Bourguignon__ http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk
next prev parent reply other threads:[~2015-08-06 20:00 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-31 21:42 How to iterate over properties in a plist? Marcin Borkowski
2015-07-31 22:18 ` Stefan Monnier
2015-07-31 22:29 ` Marcin Borkowski
2015-07-31 22:42 ` Dmitry Gutov
2015-08-01 13:34 ` Michael Heerdegen
[not found] ` <mailman.7705.1438381807.904.help-gnu-emacs@gnu.org>
2015-07-31 23:33 ` Pascal J. Bourguignon
2015-08-01 22:49 ` Stefan Monnier
[not found] ` <mailman.7750.1438469396.904.help-gnu-emacs@gnu.org>
2015-08-04 10:15 ` plists, alists, and hashtables (was: How to iterate over properties in a plist?) Ted Zlatanov
2015-08-04 10:29 ` Nicolas Petton
[not found] ` <mailman.7809.1438684158.904.help-gnu-emacs@gnu.org>
2015-08-04 11:23 ` plists, alists, and hashtables Ted Zlatanov
2015-08-05 4:36 ` plists, alists, and hashtables (was: How to iterate over properties in a plist?) Rusi
2015-08-05 6:12 ` plists, alists, and hashtables Pascal J. Bourguignon
2015-08-05 9:47 ` Ted Zlatanov
2015-08-05 12:20 ` Rusi
2015-08-06 19:16 ` Stefan Monnier
[not found] ` <mailman.7892.1438888819.904.help-gnu-emacs@gnu.org>
2015-08-07 16:33 ` Rusi
2015-08-05 17:24 ` Pascal J. Bourguignon
2015-08-05 18:31 ` Ted Zlatanov
2015-08-05 19:30 ` Barry Margolin
2015-08-05 19:40 ` Robert Thorpe
2015-08-05 21:11 ` Pascal J. Bourguignon
2015-08-06 15:17 ` Ted Zlatanov
2015-08-06 18:46 ` Pascal J. Bourguignon
2015-08-06 20:19 ` Drew Adams
2015-08-06 21:08 ` Ted Zlatanov
2015-08-07 0:23 ` Pascal J. Bourguignon
2015-08-06 19:35 ` Stefan Monnier
2015-08-05 13:48 ` Drew Adams
2015-08-06 19:12 ` Stefan Monnier
[not found] ` <mailman.7890.1438888393.904.help-gnu-emacs@gnu.org>
2015-08-06 20:00 ` Pascal J. Bourguignon [this message]
2015-08-06 20:57 ` Ted Zlatanov
2015-08-06 21:10 ` Drew Adams
[not found] ` <mailman.7902.1438895429.904.help-gnu-emacs@gnu.org>
2015-08-06 21:15 ` Ted Zlatanov
2015-08-06 21:31 ` Stefan Monnier
2015-08-07 1:53 ` Ted Zlatanov
2015-08-07 7:34 ` Pascal J. Bourguignon
2015-08-07 16:32 ` Stefan Monnier
[not found] ` <mailman.7941.1438965165.904.help-gnu-emacs@gnu.org>
2015-08-08 3:48 ` Pascal J. Bourguignon
2015-08-08 13:42 ` Stefan Monnier
2015-08-08 14:51 ` Rusi
2015-08-07 0:08 ` Pascal J. Bourguignon
2015-08-07 2:14 ` Ted Zlatanov
2015-08-07 7:53 ` Pascal J. Bourguignon
2015-08-07 11:21 ` Ted Zlatanov
2015-08-07 11:47 ` Pascal J. Bourguignon
2015-08-07 17:21 ` Ted Zlatanov
2015-08-07 19:21 ` Stefan Monnier
[not found] ` <mailman.7952.1438975314.904.help-gnu-emacs@gnu.org>
2015-08-08 3:52 ` Pascal J. Bourguignon
2015-08-07 16:35 ` Stefan Monnier
[not found] <mailman.7856.1438803631.904.help-gnu-emacs@gnu.org>
2015-08-05 20:08 ` Ted Zlatanov
2015-08-05 20:45 ` Stefan Monnier
2015-08-05 21:36 ` Drew Adams
2015-08-05 21:41 ` Pascal J. Bourguignon
[not found] ` <mailman.7860.1438807554.904.help-gnu-emacs@gnu.org>
2015-08-06 1:32 ` Ted Zlatanov
[not found] ` <mailman.7862.1438810623.904.help-gnu-emacs@gnu.org>
2015-08-06 1:36 ` Ted Zlatanov
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