From ceb333844fd9e76e1de9bcbdba748f57bc603591 Mon Sep 17 00:00:00 2001
From: Ingo Schwarze <schwarze@openbsd.org>
Date: Wed, 2 Sep 2015 15:38:35 +0000
Subject: Recommend an unambiguous escape for minus signs instead of \-.

Historically, \- was used in troff for three cases: flags/pathnames,
en dashes, and minus signs. mandoc_char(7) currently recommends it
for minus signs, recommends \(en for en dashes, and doesn't mention
flags/pathnames.

In the old days, nroff rendered \- as ASCII '-', and troff rendered
it as en dash/minus (which were visually indistinguishable).

In Unicode, en dashes and minus signs are semantically distinct and
encoded differently (U+2013 for en dash, U+2212 for minus), and
often rendered differently too. Meanwhile ASCII '-' has been renamed
"hyphen-minus" and fonts typically render it closest to a hyphen, not
a minus.

There is very little consistency across roff implementations and output
formats for what Unicode character \- corresponds to. So at least for
minus signs, change the recommendation to the unambiguous \(mi escape.

from bentley@, ok jmc@ (after reams of discussion)
---
 mandoc_char.7 | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

(limited to 'mandoc_char.7')

diff --git a/mandoc_char.7 b/mandoc_char.7
index 474fba20..d272080f 100644
--- a/mandoc_char.7
+++ b/mandoc_char.7
@@ -1,4 +1,4 @@
-.\"	$Id: mandoc_char.7,v 1.62 2015/03/30 16:06:14 schwarze Exp $
+.\"	$Id: mandoc_char.7,v 1.63 2015/09/02 15:38:35 schwarze Exp $
 .\"
 .\" Copyright (c) 2003 Jason McIntyre <jmc@openbsd.org>
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -16,7 +16,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: March 30 2015 $
+.Dd $Mdocdate: September 2 2015 $
 .Dt MANDOC_CHAR 7
 .Os
 .Sh NAME
@@ -49,7 +49,7 @@ names; instead, provide ASCII transcriptions of the names.
 .Ss Dashes and Hyphens
 In typography there are different types of dashes of various width:
 the hyphen (-),
-the minus sign (\-),
+the minus sign (\(mi),
 the en-dash (\(en),
 and the em-dash (\(em).
 .Pp
@@ -64,10 +64,10 @@ lorry-driver
 .Pp
 The mathematical minus sign is used for negative numbers or subtraction.
 It should be written as
-.Sq \e- :
+.Sq \e(mi :
 .Bd -unfilled -offset indent
-a = 3 \e- 1;
-b = \e-2;
+a = 3 \e(mi 1;
+b = \e(mi2;
 .Ed
 .Pp
 The en-dash is used to separate the two elements of a range,
@@ -720,7 +720,7 @@ In
 .Fl T Ns Cm ascii ,
 the
 \e(ss, \e(nm, \e(nb, \e(nc, \e(ib, \e(ip, \e(pp, \e[sum], \e[product],
-\e[coproduct], \e(gr, \e(\-h, and \e(a. special characters render
+\e[coproduct], \e(gr, \e(-h, and \e(a. special characters render
 differently between mandoc and groff.
 .It
 In
-- 
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