From: Michael Heerdegen <michael_heerdegen@web.de>
To: Alan Mackenzie <acm@muc.de>
Cc: Eli Zaretskii <eliz@gnu.org>,
Stephen Berman <stephen.berman@gmx.net>,
Oleh Krehel <ohwoeowho@gmail.com>,
Stefan Monnier <monnier@iro.umontreal.ca>,
Emacs Development <emacs-devel@gnu.org>
Subject: Re: pcase docstring tweaks
Date: Tue, 27 Oct 2015 15:54:23 +0100 [thread overview]
Message-ID: <87bnbkicps.fsf@web.de> (raw)
In-Reply-To: <87h9lf95qn.fsf_-_@web.de> (Michael Heerdegen's message of "Sun, 25 Oct 2015 02:00:48 +0200")
Hello,
Stefan, ok to install this?
And as I said before: anyone is invited to bike shedding ;-)
> Let's continue with the `pcase' docstring. I think it's already quite
> good. Here is a patch emphasizing that EXP is actually evaluated (I
> think that is not evident) and some more or less cosmetic changes. Is
> it clear then?
>
>
> *** /tmp/ediff17164yyt 2015-10-25 01:54:53.175155728 +0200
> --- /home/micha/software/emacs/lisp/emacs-lisp/pcase.el 2015-10-25 00:35:23.999856799 +0200
> ***************
> *** 107,113 ****
>
> ;;;###autoload
> (defmacro pcase (exp &rest cases)
> ! "Perform ML-style pattern matching on EXP.
> CASES is a list of elements of the form (PATTERN CODE...).
>
> Patterns can take the following forms:
> --- 107,113 ----
>
> ;;;###autoload
> (defmacro pcase (exp &rest cases)
> ! "Eval EXP and perform ML-style pattern matching on that value.
> CASES is a list of elements of the form (PATTERN CODE...).
>
> Patterns can take the following forms:
> ***************
> *** 115,123 ****
> SYMBOL matches anything and binds it to SYMBOL.
> (or PAT...) matches if any of the patterns matches.
> (and PAT...) matches if all the patterns match.
> ! \\='VAL matches if the object is `equal' to VAL
> ATOM is a shorthand for \\='ATOM.
> ! ATOM can be a keyword, an integer, or a string.
> (pred FUN) matches if FUN applied to the object returns non-nil.
> (guard BOOLEXP) matches if BOOLEXP evaluates to non-nil.
> (let PAT EXP) matches if EXP matches PAT.
> --- 115,123 ----
> SYMBOL matches anything and binds it to SYMBOL.
> (or PAT...) matches if any of the patterns matches.
> (and PAT...) matches if all the patterns match.
> ! \\='VAL matches if the object is `equal' to VAL.
> ATOM is a shorthand for \\='ATOM.
> ! when ATOM is a keyword, an integer, or a string.
> (pred FUN) matches if FUN applied to the object returns non-nil.
> (guard BOOLEXP) matches if BOOLEXP evaluates to non-nil.
> (let PAT EXP) matches if EXP matches PAT.
> ***************
> *** 131,141 ****
> which is the value being matched.
> So a FUN of the form SYMBOL is equivalent to one of the form (FUN).
> FUN can refer to variables bound earlier in the pattern.
> - FUN is assumed to be pure, i.e. it can be dropped if its result is not used,
> - and two identical calls can be merged into one.
> E.g. you can match pairs where the cdr is larger than the car with a pattern
> like \\=`(,a . ,(pred (< a))) or, with more checks:
> \\=`(,(and a (pred numberp)) . ,(and (pred numberp) (pred (< a))))
>
> Additional patterns can be defined via `pcase-defmacro'.
> Currently, the following patterns are provided this way:"
> --- 131,141 ----
> which is the value being matched.
> So a FUN of the form SYMBOL is equivalent to one of the form (FUN).
> FUN can refer to variables bound earlier in the pattern.
> E.g. you can match pairs where the cdr is larger than the car with a pattern
> like \\=`(,a . ,(pred (< a))) or, with more checks:
> \\=`(,(and a (pred numberp)) . ,(and (pred numberp) (pred (< a))))
> + FUN is assumed to be pure, i.e. it can be dropped if its result is not used,
> + and two identical calls can be merged into one.
>
> Additional patterns can be defined via `pcase-defmacro'.
> Currently, the following patterns are provided this way:"
Thanks,
Michael.
next prev parent reply other threads:[~2015-10-27 14:54 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 ` Michael Heerdegen [this message]
2015-10-27 18:57 ` pcase docstring tweaks 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
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