From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Newsgroups: gmane.emacs.help Subject: Re: The correspondence of the command-name and its key-sequence. Date: Mon, 11 Jan 2021 10:51:55 +0100 Message-ID: <20210111095155.GB23284@tuxteam.de> References: <62acbe7b-18f5-4b76-9f05-265218a58db7@default> <87mtxiecxq.fsf@omarpolo.com> <87h7nqe8gb.fsf@omarpolo.com> <87im83q3z5.fsf@omarpolo.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="cvVnyQ+4j833TQvp" Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="13685"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/1.5.21 (2010-09-15) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Jan 11 10:52:54 2021 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kytsb-0003RK-70 for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 11 Jan 2021 10:52:53 +0100 Original-Received: from localhost ([::1]:55022 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kytsY-0000FR-6c for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 11 Jan 2021 04:52:51 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:52386) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kytrx-0000DT-6r for help-gnu-emacs@gnu.org; Mon, 11 Jan 2021 04:52:13 -0500 Original-Received: from mail.tuxteam.de ([5.199.139.25]:52124) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.90_1) (envelope-from ) id 1kytrq-0002H2-Eh for help-gnu-emacs@gnu.org; Mon, 11 Jan 2021 04:52:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tuxteam.de; s=mail; h=From:In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:To:Date; bh=5ArHp0CRYwZSFqUhZfeCt+iZPHGYY4e95x7fmpd0wps=; b=o3/JqhNZn+ygS12tFMBkmCs1vjivWCNC0DwYLSbeSbtMnJ1kWAI0Vc4Ty6cEV7WhcoV1EEcx1bTIdY2+BW7KO7MN0FWeAB7WKgU3Nd0o8QIP6MpEu0I4hwohmP3zZyMz/BNYR+Hmr2r+11OnivX0uFcSaV53brYI6AITnokMJ9/lWuysKFoK03EUUIL+5yBFYfxl13glyY3eACDSeWb5b2gIk7pOtkBs56mhMdfynKjB0YX6U2c131ZxyDK0gLV2jxSZsVhfOrM4TAfale/FByX/pFylQPP4QrmpMjD4akmDmtw182eahe00KbpBdOkbKGDonf5OdS7aHPDbptqSgg==; Original-Received: from tomas by mail.tuxteam.de with local (Exim 4.80) (envelope-from ) id 1kytrf-0006WE-9Y for help-gnu-emacs@gnu.org; Mon, 11 Jan 2021 10:51:55 +0100 Content-Disposition: inline In-Reply-To: <87im83q3z5.fsf@omarpolo.com> Received-SPF: pass client-ip=5.199.139.25; envelope-from=tomas@tuxteam.de; helo=mail.tuxteam.de X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:127182 Archived-At: --cvVnyQ+4j833TQvp Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jan 11, 2021 at 09:20:46AM +0100, Omar Polo wrote: >=20 > Hongyi Zhao writes: >=20 > > On Sat, Jan 9, 2021 at 6:00 PM Omar Polo wrote: > > [...] > > > > Why the \ has two forms in the ascii document as shown below: > > > > $ man ascii | grep -F '\\' > > 034 28 1C FS (file separator) 134 92 5C = \ '\\' > > > > As you can see, the document gives two forms of it: > > > > \ '\\' >=20 > I guess, but it's only a guess, that's because \ is used for escaping > chars. The man page quoted above confirms your guess. Let me quote some relevant lines (elisions marked with [...]): man ASCII: | DESCRIPTION | ASCII is the American Standard Code for Information Interchange. | It is a 7-bit code. Many 8-bit codes (e.g., ISO 8859-1) contain ASCII | as their lower half. The international counterpart of | ASCII is known as ISO 646-IRV. |=20 | The following table contains the 128 ASCII characters. |=20 | C program '\X' escapes are noted. |=20 | Oct Dec Hex Char Oct Dec Hex Char | =E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94= =80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80= =E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2= =94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94= =80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80= =E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2= =94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94= =80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80= =E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80=E2=94=80 | 000 0 00 NUL '\0' (null character) 100 64 40 @ | 001 1 01 SOH (start of heading) 101 65 41 A | 002 2 02 STX (start of text) 102 66 42 B | [...] | 032 26 1A SUB (substitute) 132 90 5A Z | 033 27 1B ESC (escape) 133 91 5B [ | 034 28 1C FS (file separator) 134 92 5C \ '\\' | 035 29 1D GS (group separator) 135 93 5D ] The relevant bit is the phrase above "C program '\X' escapes are noted". Background is that, for C character and string literal notation, an "escape convention" is used: whenever you want to write a non-printable character, you use a so-called "escape character" followed by something else. For example, for a newline character, you say '\n', the escape being the '\'. Now what do you do when trying to represent the escape character itself? You just double it, like so: '\\'. For lots of background, history, and the different conventions in use, the Wikipedia page [1] is, as often, a great resource. Cheers [1] https://en.wikipedia.org/wiki/Escape_character - t --cvVnyQ+4j833TQvp Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAl/8H7sACgkQBcgs9XrR2kauEQCfTOHsjkFu1MHZ9wxydPcgKKkT 32MAniE6CnqOb/ni4wVWR32WKw9IeiMd =03dU -----END PGP SIGNATURE----- --cvVnyQ+4j833TQvp--