Re: Another issue in Groff documentation section 5.1.9 Input Encodings - phrasing

[G. Branden Robinson]

At 2024-03-08T04:07:25+0000, ropers wrote:
> Groff documentation section 5.1.9 Input Encodings
> <https://www.gnu.org/software/groff/manual/groff.html#Input-Encodings>
> contains this paragraph:
> 
> > Because a Euro glyph was not historically defined in PostScript
> > fonts, groff comes with a font called freeeuro.pfa that provides the
> > Euro in several styles. Standard PostScript fonts contain the glyphs
> > from Latin-5 and Latin-9 that Latin-1 lacks, so these encodings are
> > supported for the ps and pdf output devices as groff ships, while
> > Latin-2 is not.
> 
> That seems a little ambiguous.  I'm not actually sure if I understand
> what the author really meant by "while Latin-2 is not [supported]".
> Did they mean to say only Latin-2 really needs that freeeuro.pfa
> anymore for lack of support in standard PS fonts?   Did they mean the
> exact opposite, i.e. Latin-2 won't work with that font but the others
> will?  Did they mean PS/PDF output is completely broken for Latin-2?
> It's a little unclear given the context and given the way that is put.
> Also, the author's intent with the "as groff ships" clause could be
> clearer.

This is a fair criticism.

What it is trying to say (I'm...75% confident?) is that because the
old-school PostScript fonts groff supported 25+ years ago[1] (and that
shipped in printers, so they mattered to a lot of users) didn't
(always?) have full coverage of the ISO Latin-2 character set, so groff
couldn't be relied upon to produce satisfactory output for input that
required the relevant glyphs.

However, my current understanding is that _if_ you use (have installed,
and configure groff to employ) appropriately featureful replacement
fonts, like the notorious URW fonts our "configure" script goes hunting
for, you can render "Latin-2" documents in PostScript and PDF all day
long.  (They won't really be encoded in Latin-2, at least in the PDF
case--I don't know what PostScript does.)

In general, our Texinfo manual is not parameterized in groff
configuration options.  I've recently landed a change to make it easier
to do so, but the only really goal I have for that is to stop sticking
the 'g' prefix on the names of groff commands for platforms where it
won't be used, which is...most of them.

I'm a little leery of further conditionalizing or complicating text in
our Texinfo manual for this purpose.

I suspect a superior solution to that _and_ to recasting this paragraph
would be a more complete discussion of font availability, font
description files, and what glyphs renderings these enable.

It's one of the few areas of our Texinfo manual ("Using Symbols") I have
not yet heavily revised; this is mainly because the internals of glyph
resolution in GNU troff are complex and a person, it would seem, needs a
strong command of formatter internals to discuss them accurately.

Regards,
Branden

[1] the approximate age of Trent Fisher's original version of our
    Texinfo manual

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