Re: Escaping quotes in docstrings, Was: A simple solution to "Upcoming loss of usability ..."

[Paul Eggert]

Dmitry Gutov wrote:

> It's the same if you copy some syntax-highlighted text (say, from src/doc.c) to
> /tmp/foo and save it. Kill the buffer, reopen - the highlighting is gone! :)
> That may seem counter-intuitive, but it's something Emacs users are generally
> familiar with.

I've seen highlighting vanish, but I've never seen the characters change. 
Anyway....

> > How about the following idea instead.  Instead of displaying grave
> > accent and apostrophe specially, have with-help-window transliterate
> > these characters in place before displaying itself as usual.
>
> That should work, too. In help-mode-finish, before help-make-xrefs.

OK, let's shoot for that instead.

> For us to go there, could you please make substitute-command-keys add the
> `escaped' property to the escaped characters in its output? And push it to
> scratch/quote-escaping.

OK, I'll look into that.

> > > +               (unless (get-text-property mbeg 'help-value)
> >
> > Supposed the matched string is partly help-value, and partly not.  E.g.,
> > mbeg has help-value but mbeg+1 does not but mbeg+2 does.  Shouldn't this
> > test that all the matched characters are not help-value characters?
>
> Why? I'm assuming the value is separated from the other contents by whitespace
> or newlines.

I don't think that's a safe assumption.  It's common for quoted help-values to 
be jammed into the middle of other text.

> > > +                                 (buffer-substring-no-properties
> > > +                                  mend (1+ mend)))
> >
> > This may go haywire if it returns "\t", because a TAB is special to
> > compose-region.  Also, what if the buffer has some properties other than
> > help-value that should be preserved?
>
> Err, I don't think the current code deletes any existing properties, it only
> changes how the buffer looks.

But buffer-substring-no-properties has no properties in the result, right?  So 
effectively they're removed.  And what about the TAB?