From: Artur Malabarba <bruce.connor.am@gmail.com>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: emacs-devel <emacs-devel@gnu.org>
Subject: Re: pcase-dolist
Date: Wed, 8 Jul 2015 20:44:17 +0100 [thread overview]
Message-ID: <CAAdUY-JsnrUMUuMR4Dccn0OAUe6K4i_iQa0Nc7Q+javsxzkhAw@mail.gmail.com> (raw)
In-Reply-To: <87y4iqh7x0.fsf@web.de>
>> > Anyway, an idea that came to my mind more than once: `when-let',
>> > `if-let' should really be `pcase-when-let' , `pcase-if-let'. They
>> > would be much more useful than the plain versions I think.
>>
>> Yes, feel free to change them that way.
>
> Though, just changing them would break existing code (the current
> versions are about boolean values, the pcase versions would be about
> pattern matching).
>
> For example, now
>
> (if-let ((a (ignore))) a 17) ==> 17,
>
> but
>
> (pcase-if-let ((a (ignore))) a 17) ==> nil.
Only if you make them like this. The idea of `(if-let ((a expr))
body)' is that evaluate `expr' and, if it is non-nil, bind it to a and
run `body'. This doesn't exclude the possibility of `a' being a pcase
pattern. Just make sure that the the check for nil expr is done as a
separate thing, before the pattern matching.
If you implement pcase-if-let the way you suggest above, isn't that
just the same as pcase?
next prev parent reply other threads:[~2015-07-08 19:44 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-08 12:20 pcase-dolist Michael Heerdegen
2015-07-08 13:54 ` pcase-dolist Stefan Monnier
2015-07-08 17:32 ` pcase-dolist Michael Heerdegen
2015-07-08 18:26 ` pcase-dolist Tassilo Horn
2015-07-08 21:27 ` pcase-dolist Stefan Monnier
2015-07-09 6:05 ` pcase-dolist Tassilo Horn
2015-07-09 9:55 ` pcase-dolist Thierry Volpiatto
2015-07-09 10:17 ` pcase-dolist Tassilo Horn
2015-07-09 12:19 ` pcase-dolist Thierry Volpiatto
2015-07-09 13:34 ` pcase-dolist Tassilo Horn
2015-07-09 13:40 ` pcase-dolist Thierry Volpiatto
2015-07-09 19:26 ` pcase-dolist Stefan Monnier
2015-07-09 20:27 ` pcase-dolist Michael Heerdegen
2015-07-10 18:51 ` pcase-dolist Stefan Monnier
2015-10-12 11:27 ` pcase-setq (was: pcase-dolist) Michael Heerdegen
2015-10-12 11:54 ` pcase-setq Michael Heerdegen
2015-10-12 12:01 ` pcase-setq (was: pcase-dolist) Nicolas Petton
2015-10-12 12:36 ` pcase-setq Michael Heerdegen
2015-10-12 12:49 ` Semantic of pcase `seq' and `map' patterns (was: pcase-setq) Michael Heerdegen
2015-10-12 13:41 ` Semantic of pcase `seq' and `map' patterns Michael Heerdegen
2015-10-12 13:55 ` Nicolas Petton
2015-10-12 14:02 ` Michael Heerdegen
2015-10-17 12:21 ` Michael Heerdegen
2015-10-17 13:31 ` Nicolas Petton
2015-10-12 13:50 ` Semantic of pcase `seq' and `map' patterns (was: pcase-setq) Nicolas Petton
2015-10-13 0:59 ` pcase-setq Stefan Monnier
2015-10-13 13:52 ` pcase-setq Michael Heerdegen
2015-10-13 14:02 ` pcase-setq Michael Heerdegen
2015-10-13 15:52 ` pcase-setq Michael Heerdegen
[not found] ` <jwvfv1eboo8.fsf-monnier+emacs@gnu.org>
[not found] ` <87d1wh36as.fsf@web.de>
2015-10-14 15:49 ` pcase-setq Stefan Monnier
2015-07-10 14:44 ` pcase-dolist Tassilo Horn
2015-07-10 19:04 ` pcase-dolist Stefan Monnier
2015-07-08 19:44 ` Artur Malabarba [this message]
2015-07-08 20:50 ` pcase-dolist Michael Heerdegen
-- strict thread matches above, loose matches on Subject: below --
2014-07-11 10:35 pcase-dolist Sebastian Wiesner
2014-07-11 13:47 ` pcase-dolist Stefan Monnier
2014-07-11 13:50 ` pcase-dolist Sebastian Wiesner
2014-07-11 14:14 ` pcase-dolist Stefan Monnier
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