Re: [groff] [patch] modernize -T ascii rendering of opening single quote

[Ingo Schwarze]

Hi,

Ingo Schwarze wrote on Wed, Feb 20, 2019 at 08:06:17PM +0100:

> So i think it is best that i do not commit my patch, do not change
> the behaviour of the mandoc toolkit either, close the bugtracker
> ticket as WONTFIX in a few days,

Done.

> and instead consider whether the
> mandoc_char(7) manual or the "ASCII Output" section in the mandoc(1)
> manual should instead explain why the ASCII output device renders
> single quotes as 0x60/0x27 - which, as the thread has extensively
> demonstrated, is no longer obvious even for some experienced computer
> users nowadays.

Done, too, see the addition to the mandoc(1) "ASCII output" chapter
in the patch below.

Do we want something similar in the groff documentation?

If so, the logical place where it would have to go would be grotty(1),
right?  Even though that does not have a section specifically about
-T ascii so far nor anything about the representation of individual
characters...

Yours,
  Ingo


Log Message:
-----------
Explain the ASCII rendering of single quotes because that repeatedly
caused confusion in the past.  People plainly do not expect that 
there are limits to the compatibility between Unicode and ASCII,
but there are.

The information belongs here and not into mandoc_char(7) because
it explains how the specific output device (-T ascii) works and
because it has nothing to do with the question of how characters
are represented on the input side.

Modified Files:
--------------
    mandoc:
        mandoc.1

Revision Data
-------------
Index: mandoc.1
===================================================================
RCS file: /home/cvs/mandoc/mandoc/mandoc.1,v
retrieving revision 1.236
retrieving revision 1.237
diff -Lmandoc.1 -Lmandoc.1 -u -p -r1.236 -r1.237
--- mandoc.1
+++ mandoc.1
@@ -267,6 +267,17 @@ instead.
 The special characters documented in
 .Xr mandoc_char 7
 are rendered best-effort in an ASCII equivalent.
+In particular, opening and closing
+.Sq single quotes
+are represented as characters number 0x60 and 0x27, respectively,
+which agrees with all ASCII standards from 1965 to the latest
+revision (2012) and which matches the traditional way in which
+.Xr roff 7
+formatters represent single quotes in ASCII output.
+This correct ASCII rendering may look strange with modern
+Unicode-compatible fonts because contrary to ASCII, Unicode uses
+the code point U+0060 for the grave accent only, never for an opening
+quote.
 .Pp
 The following
 .Fl O