RE: EWW improvements: open in new buffer, tags, quickmarks, search engines, ...

[Drew Adams <drew.adams@oracle.com>]

> >> As far as I understand, Emacs native bookmarks won't work with EWW.
> >> `M-x bookmark-set' complains the the EWW buffer does not point to a
> >> real file.
> >
> > No, normal Emacs bookmarks do not need a file as
> > target.  Even vanilla Emacs can bookmark Dired and
> > Info nodes (albeit not so well).  A bookmark handler
> > can do anything you want it to do.
> 
> Can you explain how you bookmark an EWW buffer with Emacs
> vanilla bookmarks?

A new type of bookmark needs to be defined, with a handler
that "jumps" to the URL.  Code from Bookmark+ or similar
could be used.

My point was that just to add EWW support for (real)
Emacs bookmarks it's not required to add all of Bookmark+
to Emacs.  All that's needed are to define a format for
the bookmarks and define a hander function to jump to
such a bookmark.

In Bookmark+, the handler function is `bmkp-jump-eww',
and a bookmark with EWW format is made by function
`bmkp-make-eww-record'.

(defun bmkp-make-eww-record ()
  "Make a record for an EWW buffer."
  `(,(bmkp-eww-title)
    (buffer-name . ,(bmkp-eww-new-buffer-name))
    ,@(bookmark-make-record-default 'NO-FILE)
    (location . ,(bmkp-eww-url))
    (handler . bmkp-jump-eww)))

The logic behind jumping to an EWW bookmark, and how
that is hooked into EWW is more complicated - see the
Bookmark+ code for how Bookmark+ does it.

> Besides it does not seem to effectively work with many other modes.  For
> instance, bookmarking a *Help* buffer works at first glance, but Emacs
> fails to look read the bookmarks file upon restart.

Dunno what that means.  But yes, vanilla Emacs needs
to have some support for bookmarking arbitrary buffers,
as does Bookmark+, or else it needs to at least have
support for bookmarking some specific kinds of
bookmarks (*Info*, *Help* or whatever).

But I believe that vanilla Emacs already does have
support for bookmarking some kinds of buffers, such
as Info and Dired.  I don't recall really, but I was
thinking it does when I wrote that.  Emacs added
bookmark field `location', for example, and its value
need not be a file name.

In any case, the infrastructure is there in vanilla
Emacs to do any of this.

My point was: 

1. Bookmark+ is freely available.  It can be
   integrated into Emacs; and it already provides
   EWW support.

2. It's not _necessary_ to integrate Bookmark+ to add
   EWW support to Emacs.  That could be done either
   by just copying the Bookmark+ EWW-support code to
   Emacs or by Emacs rolling its own support.

3. In reply to your statement that vanilla Emacs
   requires that a bookmark target a file I replied
   that I don't think that's true.

   Grepping the Emacs source code for "'location"
   shows only one use of that property, in
   `gnus-summary-bookmark-jump', and I might be
   reading that wrong, so I could be wrong about this.

   There are other ways than property `location' to do
   this, so grepping `location" (no preceding quote')
   might tell more.

   And I see that an Info bookmark records both the
   Info file and the node (so it does record a file
   name).

   Grepping for `bookmark-default-handler' can also
   tell us whether some bookmark types do not record
   a file name.  Maybe `Man-bookmark-jump'?
   `doc-view-bookmark-jump'?