From: Stefan Monnier <monnier@iro.umontreal.ca>
To: "Mattias Engdegård" <mattiase@acm.org>
Cc: Emacs developers <emacs-devel@gnu.org>
Subject: Re: master ea93326: Add `union' and `intersection' to rx (bug#37849)
Date: Fri, 13 Dec 2019 12:13:19 -0500 [thread overview]
Message-ID: <jwvo8wcrw43.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <719A6AF3-9624-422A-B6E6-FC942623B5C5@acm.org> ("Mattias \=\?windows-1252\?Q\?Engdeg\=E5rd\=22's\?\= message of "Fri, 13 Dec 2019 18:03:14 +0100")
> An interesting suggestion, but exactly how would that model work? Consider:
>
> (rx-define ident-chars (any "a-z0-9"))
> (rx-define op-chars (any "+*/" ?-)
>
> To form the union of the two, 'any' needs to be allowed inside 'union':
>
> (any (union ident-chars op-chars))
Indeed to avoid this, we'd have to do something like
(rx-define-charset ident-chars "a-z0-9")
(rx-define-charset op-chars (union "+*/" ?-))
and then
... (any (union ident-chars op-chars)) ...
Is it worth the trouble?
> Speaking of 'or', we still haven't figured out what to do about regexp-opt
> in rx. Currently, the answer is something like
> (eval (regexp-opt STRINGS)), which isn't ideal.
We could try and automatically determine inside `or` when regexp-opt can
be used. That doesn't sound like much fun, tho.
Stefan
next prev parent reply other threads:[~2019-12-13 17:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191210213842.5388.30110@vcs0.savannah.gnu.org>
[not found] ` <20191210213843.EB6A520A23@vcs0.savannah.gnu.org>
2019-12-10 21:52 ` master ea93326: Add `union' and `intersection' to rx (bug#37849) Stefan Monnier
2019-12-11 11:17 ` Mattias Engdegård
2019-12-11 15:10 ` Stefan Monnier
2019-12-12 22:48 ` Mattias Engdegård
2019-12-13 13:55 ` Stefan Monnier
2019-12-13 17:03 ` Mattias Engdegård
2019-12-13 17:13 ` Stefan Monnier [this message]
2019-12-13 17:43 ` Mattias Engdegård
2019-12-13 23:03 ` Stefan Monnier
2019-12-15 11:08 ` Mattias Engdegård
2019-12-15 14:53 ` Stefan Monnier
2019-12-15 19:23 ` Mattias Engdegård
2019-12-15 20:04 ` Stefan Monnier
2019-12-15 20:42 ` Stefan Monnier
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