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

[G. Branden Robinson]

At 2019-02-20T20:06:17+0100, Ingo Schwarze wrote:
> Hi,
> 
> after reviewing all feedback, i come to the conclusion that there is no
> consensus for the change:
> 
> OPPOSED:  Mike Bianchi, Tadziu Hoffmann
> SCEPTICAL:  Ralph Corderoy
> NO EXPLICIT PREFERENCE STATED:  Doug McIlroy, Werner Lemberg
> APPEAR TO NOT OBJECT:  Dave Kemper, Jason McIntyre
> IN FAVOUR:  Anthony Bentley, Bertrand Garrigues, Colin Watson,
>             Ingo Schwarze, Jeff Conrad, Ted Unangst
> 
> I think that established behaviour can be changed if there is
> consensus.  I also think that established behaviour can be changed
> if there is an overwhelming majority together with strong technical
> reasons or very significant benefit from the change.

I'm sorry for the late arrival.  I've moved and taken a new job.

The Savannah ticket[1] says:

"If i remember correctly, some time ago, people went through error
messages and manual pages and changed single-quoted strings where the
opening quote was an "accent grave" to the normal ASCII U+0027
APOSTROPHE-QUOTE because rendering single quotes like `this' was
considered an anachronism from the mechanical typewriter era."

I'm one of those people, and I particularly did it for diagnostic
messages.  The GNU Coding Standards no longer prescribe using
"symmetric" quotation marks drawn from valid ASCII code points, for the
very good reason that they don't exist in modern fonts.

My view is as follows:

1.  I would not mess with the ASCII device because `this' is sometimes a
reasonable way to get symmetric quotes on an _actual_ ASCII output
device.  I wouldn't _recommend_ it as it's not forward-compatible.  It's
fine for roff input just as it is in TeX, even if it looks a little
funny in document maintenance on fancy modern systems.  Were the issue
important enough, we could have separate ascii_60_is_oq and
ascii_60_is_ga devices (or whatever we ended up naming them).  In my
opinion the ambiguity deliberately baked into ASCII in the 1960s was
unfortunate, and doubly so because both Knuth and the *roff progenitors
decided on DWIM semantics for ` and ', building heavily on that
ambiguity.  Cf. `foo' and `bar', \('a and \'a, speaking in *roff first
and then TeX, respectively, in each pair.

(I grant that the ASCII [ASA, ANSI] committee had a hard job.  The
temptation must have been great to placate partisans by mapping multiple
semantics onto each glyph to inflate the encoding's "coverage".  Douglas
Kerr has some interesting anecdotes about Bell yielding to the ASCII
then-future by replacing the 5-pointed star and diamond lozenge symbols
on their then-innovative touch-tone phone keypads with the mysterious
"asterisk" and "octatherp/octotherp/octothorpe" symbols.[2][3])

2.  I _would_ change the latin1 device because there is no rational
defense of 0x60 ` as an opening quote in Latin-1 (a.k.a. ISO 8859-1).
In Latin-1 (and I think all the other ISO Latin alphabets, including
ISO 8859-15), 0x60 is the GRAVE ACCENT and is never[4] mirror-symmetric
with 0x27 ' APOSTROPHE but is instead mirror-symmetric with 0xB4 ´ ACUTE
ACCENT.

On truly ASCII output devices, 0x60 GRAVE ACCENT _might_ be a
directional single quotation mark that pairs with 0x27; it therefore
makes sense to map \[oq] to 0x60.  It consequently makes sense to have
\[cq] and \[aq] map to the same glyph, 0x27 APOSTROPHE.

On a Latin-1, Windows-1252, or Unicode device, the foregoing WILL NOT
be true.  Latin-1 lacks directional quotation marks altogether, and the
other two encodings have dedicated code points for them, respecting 0x60
in its sole role as a spacing grave accent diacritic.  On none of these
will 0x27 APOSTROPHE be a copy of 0xB4 ACUTE ACCENT.

So I move to proceed with the patch to devlatin1.  We can then see who
claims to be defending the honor of the 7-bit ASCII tradition when
they've actually been using something else the whole time.

[1] https://savannah.gnu.org/bugs/index.php?55616

[2] http://dougkerr.net/Pumpkin/articles/Octatherp-octotherp.pdf

[3] I'm sure glad Kerr's preferred "octatherp" never gained traction.
Sounds to me like medical school slang for the 8 different ways to
contract herpes.

[4] Yup, I'm saying "never".  I defy the reader to come up with a
counterexample (without creating one) and I'd be interested to see it.

Regards,
Branden

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