bug#3516: 23.0.94; function key names in Info

[Eli Zaretskii <eliz@gnu.org>]

> From: "Drew Adams" <drew.adams@oracle.com>
> Date: Wed, 10 Jun 2009 15:33:50 -0700
> 
> > > We see things like <F1>, <F2>, <RET>, and <ESC> without single
> > > quotes. Similarly, in other parts of the manual.
> > >  
> > > Shouldn't those be `<f1>', `<f2>', `<RET>', and `<ESC>'?
> > >  
> > > We use `C-x <RET>' here, and we use `C-x', but not `<RET>'. 
> > > Likewise, we use `<ESC>C-h' (which should be `<ESC> C-h', BTW),
> > > but not `<ESC>'.
> > >  
> > > The notation used does not seem consistent.
> > > Why write "(`C-h' or <F1>)", instead of "(`C-h' or `<F1>')"?
> > 
> > Please show here the Texinfo sources, not just the text from the Info
> > manual.  I'm not saying that all you report is necessarily correct,
> > but it could be: ESC and RET are both characters and keys.  In the
> > character context, ESC and RET are correct, while in the key context,
> > `<ESC>' and `<SPC>' are correct (the latter comes from @key, and I
> > don't remember now whether @key produces the quotes in addition to
> > <..>).
> 
> I don't have the Texinfo sources.
> 
> I'm just an Emacs user reporting what seems to be an Emacs bug - in Info.

You are more than "just a user", Drew, let's be honest.

Anyway, at least provide these quotes with context.  Grepping through
Info files for "<SPC>" and the likes is no fun.  Since you already
look at the surrounding text, pasting it into the bug report should
be easy.

> For my part, I was referring to (or trying to refer to) passages that talk about
> keys, not characters. To me, key sequences should be wrapped in `...', even when
> they have <...>. To me, the key sequence should be written `<SPC>' even if the
> character is written SPC.

We use <ESC> and such likes for keyboard keys that are labeled with
more than a single character.  The issue here is to prevent confusion
on the reader's part between a single key labeled "ESC" and a sequence
of 3 keys E, S, C.

When a key is labeled with a single character, this confusion cannot
happen, so <..> is not used in that case, because it would just make
the reading harder with no good reason.

Likewise, key sequences such as C-k are not single keys, you actually
use 2 or more keys to type them.  So <..> is inappropriate in that
context as well.

Thus, single keys and key sequences get different markup.