From: Michael Heerdegen <michael_heerdegen@web.de>
To: Oleh Krehel <ohwoeowho@gmail.com>
Cc: Eli Zaretskii <eliz@gnu.org>, Emacs Development <emacs-devel@gnu.org>
Subject: Re: Question on pcase
Date: Mon, 26 Oct 2015 17:20:40 +0100 [thread overview]
Message-ID: <87fv0xd2jr.fsf@web.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:
> The reason I dislike `pcase' is not because I don't know how to use it
> (the basic rules are actually pretty simple), it's because I think it
> leads to code that's hard to understand, maintain and transform. I
> dislike the trivial `if-let' and `when-let' for the same reasons.
I like them because I think they make code easier to understand and
maintain.
> I generally dislike any custom macro that includes `if' or binds
> variables. This is because I can't reason about the code that uses these
> macros unless I know exactly what they do in terms of binding variables
> and selecting branches. These macros don't follow the substitution model
> for procedure application (SMPA) [1], which is a valuable debugging
> technique for me.
I wonder how you debug. With the built in debugger, with edebug,
something else? Knowing that would help understanding you problem.
> Maybe someone could explain the above, and also suggest the best way the
> create variable bindings from a pcase branch.
`macroexpand' is your only choice if you want to have semantically
equivalent code you can actually run. If arbitrary `pcase' forms could
be expanded to simpler code, well, we should rewrite `pcase' to expand
to this simpler code.
Michael.
next prev parent reply other threads:[~2015-10-26 16:20 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 [this message]
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
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