Re: Any interest in using HTML for locally-installed Texinfo documentation?

[Gavin Smith]

On Tue, Apr 02, 2019 at 11:37:51AM +0200, Ludovic Courtès wrote:
> (For some reason ‘i’ does open the index search box for me, but then
> hitting enter doesn’t produce any effect.  The other navigation commands
> work fine, though.)

It works on Firefox 53, at least.

> Yet I’m not completely sold to the everything in the browser approach,
> and everything in JavaScript.  In an ideal world (for me), we’d rather
> provide a local documentation viewer that renders Texinfo directly.
> TTN’s IXIN experiment was a step in the right direction IMO, but I
> understand this approach is not something that’s happening now.

To my knowledge, no program has ever been produced that does anything 
useful with IXIN.

Using JavaScript within a web browser has big drawbacks due to its 
"sandboxed" nature.  (You can't access environment variables, for 
example.)  However, we'd want to avoid having to re-implement too much 
of the web browser; for example, input file parsing, text layout and font 
rendering.

One thought is that there may be other "layout engines" that could be 
used, such as those in various GUI toolkits.

> When talking about ease of access, we can’t ignore keyword searches.
> How would you do ‘info -k’?

I don't know.  You would have to have some way of finding all the 
installed manuals.  This may be difficult with a standard web browser 
due to security restrictions.

> How would you even simply point your
> browser to a specific manual?

Maybe there could be a command for this within the browser.  There could 
also be a command-line program that would launch the documentation 
browser.

> What about inter-manual cross-references?
> Would we need a mechanism similar to ‘htmlxref.cnf’ but that would
> browse local manuals?

Good question.  The inter-manual links in locally-installed HTML files 
would have to be recognizable.  They could look like

<a href="../texinfo/index.html#Top">Texinfo</a>

instead of

<a 
href="https://www.gnu.org/software/texinfo/manual/texinfo/html_node/index.html#Top";>Texinfo</a>

as there were would no way of resolving the second link to a 
locally-installed file (it is not clear from the URL what the name of 
the manual even is).  It would be quite simple to get texi2any to 
output this instead.  (It can currently be done by passing '-c 
HTMLXREF=empty' where 'empty' is an empty file, but a better interface 
could be devised.)

Then inter-manual links would all work, assuming the installed manuals 
are all subdirectories of the same directory (e.g. 
/usr/share/info/html).

This doesn't address the issue of multiple installed versions of the 
same manual or manuals in different "prefix hierarchies".  I imagine the 
Info browser would interpret the "../" string specially in a link and 
go looking through a search path for the referenced manual.  Again, this 
may be difficult to implement in standard web browsers due to security 
restrictions.

> What would be the recommended solution for Emacs
> and console users?

Info files would carry on as an option.

I'm getting the feeling that we need a web browser, or something like 
it, which can integrate with the operating system a lot more, without
sandboxing or security restrictions.