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Re: Clarify `pcase' `rx' pattern doc
From: |
Michael Heerdegen |
Subject: |
Re: Clarify `pcase' `rx' pattern doc |
Date: |
Wed, 13 Jun 2018 09:59:33 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) |
Andreas Schwab <address@hidden> writes:
> On Jun 13 2018, Michael Heerdegen <address@hidden> wrote:
>
> > diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
> > index 85e74f28ef..fa2a0898d6 100644
> > --- a/lisp/emacs-lisp/rx.el
> > +++ b/lisp/emacs-lisp/rx.el
> > @@ -1183,24 +1183,25 @@ rx
> >
> >
> > (pcase-defmacro rx (&rest regexps)
> > - "Build a `pcase' pattern matching `rx' regexps.
> > -The REGEXPS are interpreted as by `rx'. The pattern matches if
> > -the regular expression so constructed matches EXPVAL, as if
> > -by `string-match'.
> > + "`pcase' pattern matching strings using `rx' REGEXPS.
>
> This sentence no verb. At least it should start with a capitalized
> word.
I can arrange that. There is a verb, but it is elided ;-) It is
arguable if it is not a sentence, I guess.
> What's wrong with the original version?
I found some things confusing; and some information is also missing:
The original version says "build a pcase pattern". This text appears in
C-h f pcase, where it sounds strange.
It says it matches rx regexps, I find it more concrete to say it matches
strings using rx regexps. It doesn't say that it raises an error if
matched against something that is not a string.
The `let' part doc speaks of a FORM where it means an rx regexp.
The `backref' part fails to say that it also accepts a positive integer
as argument, and what "backreference" actually means (is it a reference
to a pattern or to a match?).
Michael.
Re: Clarify `pcase' `rx' pattern doc, Michael Heerdegen, 2018/06/18