From: Andreas Schwab <schwab@suse.de>
To: Oleh Krehel <ohwoeowho@gmail.com>
Cc: Michael Heerdegen <michael_heerdegen@web.de>,
Eli Zaretskii <eliz@gnu.org>,
Emacs Development <emacs-devel@gnu.org>
Subject: Re: Question on pcase
Date: Mon, 26 Oct 2015 17:35:40 +0100 [thread overview]
Message-ID: <mvmd1w1h9k3.fsf@hawking.suse.de> (raw)
In-Reply-To: <87io5tzkt8.fsf@gmail.com> (Oleh Krehel's message of "Mon, 26 Oct 2015 16:55:15 +0100")
Oleh Krehel <ohwoeowho@gmail.com> writes:
> But the code that binds the variables, e.g. (setq thing x) will likely
> be hard to implement. For instance, look at this example with macroexpand:
>
> (setq test '(1 . 2))
> (pcase test
> (`(,foo . ,baz)
> (cons baz foo)))
> ;; =>
> ;; (2 . 1)
>
> (macroexpand '(pcase test
> (`(,foo . ,baz)
> (cons baz foo))))
> ;; =>
> ;; (if (consp test)
> ;; (let* ((x (car test))
> ;; (x (cdr test)))
> ;; (let ((baz x)
> ;; (foo x))
> ;; (cons baz foo)))
> ;; nil)
>
> The macroexpanded code returns (2 . 2) when evaluated. This I don't
> understand.
Try binding print-gensym and print-circle to non-nil while the form is
printed.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
prev parent reply other threads:[~2015-10-26 16:35 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-22 14:46 Question on pcase Oleh Krehel
2015-10-22 21:19 ` Michael Heerdegen
2015-10-23 6:30 ` Eli Zaretskii
2015-10-23 11:58 ` Oleh Krehel
2015-10-23 12:23 ` Michael Heerdegen
2015-10-23 12:42 ` Oleh Krehel
2015-10-23 13:07 ` Michael Heerdegen
2015-10-23 13:26 ` Oleh Krehel
2015-10-23 13:59 ` Michael Heerdegen
2015-10-27 23:50 ` Johan Bockgård
2015-10-30 1:33 ` Michael Heerdegen
2015-10-23 14:23 ` Michael Heerdegen
2015-10-23 12:17 ` Michael Heerdegen
2015-10-23 12:22 ` Oleh Krehel
2015-10-23 13:26 ` Eli Zaretskii
2015-10-23 14:14 ` Michael Heerdegen
2015-10-23 14:41 ` Eli Zaretskii
2015-10-23 18:38 ` Michael Heerdegen
2015-10-23 18:43 ` Eli Zaretskii
2015-10-23 19:59 ` Przemysław Wojnowski
2015-10-23 21:01 ` Michael Heerdegen
2015-10-23 20:23 ` Przemysław Wojnowski
2015-10-23 20:39 ` Michael Heerdegen
2015-10-24 11:37 ` Przemysław Wojnowski
2015-10-24 9:01 ` Alan Mackenzie
2015-10-24 12:58 ` Stephen Berman
2015-10-24 17:47 ` Alan Mackenzie
2015-10-24 19:10 ` Stephen Berman
2015-10-24 19:28 ` Alan Mackenzie
2015-10-25 0:00 ` pcase docstring tweaks (was: Question on pcase) Michael Heerdegen
2015-10-27 14:54 ` pcase docstring tweaks Michael Heerdegen
2015-10-27 18:57 ` Stefan Monnier
2015-10-27 20:14 ` Michael Heerdegen
2015-10-28 3:15 ` Richard Stallman
2015-10-28 17:08 ` Michael Heerdegen
2015-10-24 17:00 ` Question on pcase Drew Adams
2015-10-24 17:22 ` Alan Mackenzie
2015-10-24 17:36 ` Drew Adams
2015-10-24 20:03 ` Johan Bockgård
2015-10-24 23:11 ` Michael Heerdegen
2015-10-26 15:55 ` Oleh Krehel
2015-10-26 16:07 ` Michael Heerdegen
2015-10-27 8:42 ` Oleh Krehel
2015-10-26 16:20 ` Michael Heerdegen
2015-10-27 8:42 ` Oleh Krehel
2015-10-27 14:27 ` Michael Heerdegen
2015-10-27 14:47 ` Michael Heerdegen
2015-10-28 18:05 ` Michael Heerdegen
2015-10-29 9:44 ` Oleh Krehel
2015-10-30 1:11 ` Michael Heerdegen
2015-10-26 16:35 ` Andreas Schwab [this message]
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