From: Michael Heerdegen <michael_heerdegen@web.de>
To: Eli Zaretskii <eliz@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: Clarify `pcase' `rx' pattern doc
Date: Sat, 07 Jul 2018 15:36:04 +0200 [thread overview]
Message-ID: <8736wvf9rv.fsf@web.de> (raw)
In-Reply-To: <834lhbleol.fsf@gnu.org> (Eli Zaretskii's message of "Sat, 07 Jul 2018 09:53:30 +0300")
Eli Zaretskii <eliz@gnu.org> writes:
> > > + [...] If the target is not a string, signal an error.
> >
> > We want to change that, so I think you can drop that sentence.
>
> Shouldn't it be dropped when that change is committed?
Then we would break documented behavior then. What would be the gain?
> > But can we remove the sentence saying "Multiple occurrences of the
> > same VAR refer to the same submatch."? It's completely redundant
> > IMHO.
>
> Is it redundant even when VAR is not a submatch number, but a symbol?
I think so. A symbol VAR references the explicit binding created with
(let VAR ...), i.e. a submatch, just like in the number case.
> Btw, in this part:
>
> > + (let VAR SEXP...) creates a new explicitly numbered submatch
> > + that matches regular expressions SEXP, and
> > + binds the match to VAR.
>
> Does "explicitly numbered" mean that VAR must be a number? If it can
> be something else, perhaps "explicitly named" is better?
AFAIK, in `let' VAR must be a symbol, but it seems the submatch is also
numbered as side effect, e.g.
(pcase "Hala"
((rx "H" (let x "a") (regex ".*") (backref 1)) x))
==> "a"
In `backref' the argument can be a number or a symbol VAR. That's why I
would prefer a different argument name in the docstring, "REF" maybe. I
had done that in my suggested patch.
Michael.
next prev parent reply other threads:[~2018-07-07 13:36 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-13 3:52 Clarify `pcase' `rx' pattern doc Michael Heerdegen
2018-06-13 5:43 ` Michael Heerdegen
2018-06-13 7:33 ` Andreas Schwab
2018-06-13 7:59 ` Michael Heerdegen
2018-06-13 8:18 ` Michael Heerdegen
2018-06-13 12:29 ` Yuri Khan
2018-06-18 12:34 ` Michael Heerdegen
2018-06-18 14:11 ` Stefan Monnier
2018-06-18 14:58 ` Michael Heerdegen
2018-06-18 16:56 ` Eli Zaretskii
2018-06-18 17:22 ` Michael Heerdegen
2018-06-18 17:55 ` Eli Zaretskii
2018-06-21 11:13 ` Michael Heerdegen
2018-06-21 14:48 ` Eli Zaretskii
2018-06-21 15:13 ` Michael Heerdegen
2018-06-23 13:35 ` Eli Zaretskii
2018-07-06 17:57 ` Michael Heerdegen
2018-07-07 6:53 ` Eli Zaretskii
2018-07-07 13:36 ` Michael Heerdegen [this message]
2018-07-07 13:57 ` Eli Zaretskii
2018-07-07 14:35 ` Michael Heerdegen
2018-07-20 8:45 ` Eli Zaretskii
2018-07-20 22:56 ` Michael Heerdegen
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