Re: epub init file, and questions

[Eli Zaretskii]

> Date: Sat, 25 Dec 2021 11:44:34 -0800
> From: Per Bothner <per@bothner.com>
> 
> My proposed replacement for Emacs info mode would look for html files
> and render them using eww mode.  Eww doesn't handle JavaScript, so it
> couldn't use info.js, but the logic of info mode could be enhanced
> to work with html files instead of (or rather in addition to) info files.
> (Conceptually, it's a matter of changing eww's keybindings
> to work like info mode.)

Before this happens, the Texinfo project should define rules and
directory hierarchy for installing HTML manuals on a typical system,
in a way that will support everything that Info supports.  For
starters, cross-manual links should work regardless of whether the
manuals were generated as a single monolith file or split into
chapters or nodes.  We should also have a global index.html (or maybe
we should call it dir.html) file with a menu for all the installed
manuals, and install-info should be enhanced (or a new program
written) to produce/update such a global index.  Standard Makefile
rules should also be extended to support installation of
HTML formatted manuals, and perhaps also produce them by default.

AFAIK we never approached these issues seriously, but if we want to
lead and support the move towards using HTML formatted docs more, we
should start development and discussions in this direction ASAP.

> Note that using eww-mode running in a terminal displays texi2any-generated
> html work pretty decently, so that could potentially replace the
> standalone info program, once we have an html-supporting info mode.

Two issues with this:

  . the stand-alone Info reader is a much leaner program than Emacs
  . the eww mode is _slow_, especially on GUI displays, because it
    performs layout calculations in Lisp.  eww mode was never designed
    to handle large bodies of text.

In general, Emacs has a ways to go before it will be able to be a
decent replacement for Info for use of the HTML formatted docs,
because the features mentioned above don't yet exist in Emacs, and we
just started discussing them.  There are also quite a few features in
the Emacs Info mode that are cross-manual and some of them don't exist
in the stand-alone reader -- those will need to be rewritten to work
with HTML manuals instead.

I guess my main point is that the move to HTML docs in the GNU project
is not a simple decision, and will need at least a close cooperation
of the Emacs and Texinfo projects to create a workable system.  We
shouldn't assume that everything is already ready for that, just
because we already have HTML browsers.  A lot of non-trivial issues
need to be figured out and solved before we could have a solid
workable system.