Re: Non-standard DOS VGA Font single quote

[Alan Mackenzie <acm@muc.de>]

Hello, Eli and Ryan.

In article <mailman.14211.1504339157.21957.help-gnu-emacs@gnu.org> you wrote:
>> From: rjd <3246251196ryan@gmail.com>
>> Date: Fri, 1 Sep 2017 21:24:46 +0100

>> In general, single quotes work fine even in emacs, but for some
>> reason in *Help* buffers they look different. This also applies when
>> I compile something in shell and I get an error message

> In help buffers and error messages, Emacs attempts to use Unicode
> curly quotes on terminals that support these characters.

Surely, what we need is a customisation variable, by which the user can
chose to enable this character substitution if he wants it.

>> Anyway, I have attached the images of Perfect DOS VGA and Moder DOS
>> 437 (the latter being an okay font, but I much prefer perfect).

> What version of Emacs is that?  Emacs on MS-DOS should display these
> quotes as ASCII characters 'like this'.  For some reason, it sounds
> like Emacs thinks your terminal supports the Unicode curly quote
> characters, so it tries to display them.

> What does this produce inside Emacs:

>   M-: (char-displayable-p #x2018) RET

> ?

I think char-displayable-p is too unreliable to use for this purpose.
It doesn't work on a Linux tty, and would appear not to work on R's
terminal either.

-- 
Alan Mackenzie (Nuremberg, Germany).