planner-snap (was Re: [emacs-wiki-discuss] annotations from files: line and column numbers)

[Berkan Eskikaya]

>>>> In article <address@hidden>, Jesse Alama <address@hidden> writes:

 Jesse> Hello,
 Jesse> I appreciate being able to revisit files by following links that were
 Jesse> generated from M-x remember.  This function could be improved, IMHO,
 Jesse> if M-x remember recorded the line number of the file I was visiting at
 Jesse> the time, and perhaps the column number, too.  By following a link
 Jesse> generated in this way, not only would I revisit the file I was
 Jesse> visiting when I hit M-x remember, but I would also be put back to the
 Jesse> exact spot in the file I was looking at.


I use 'snap' from 

   http://howm.sourceforge.jp/a/snap.el

which does exactly what you wish for, at least for some modes. Attached are
planner-snap.el and snap.el.diff [my modifications to snap].

--

Snap produces URIs based on the major-mode of the buffer you invoke it
from, and for some [but not all] modes these URIs include the line number
and a context string following the point (which is equivalent to having the
column number). E.g.,

   snap:///~/elisp/snap.el#177:(defun snap-record: ()

For each major mode you want snap to support, you write two functions, 
"snap-record:MAJOR-MODE" and "snap-play:MAJOR-MODE". 

Calling 'snap-play' on a 'snap-record'ed URI opens the URI with the
relevant major mode and uses occur to find and go to the point where you
invoked snap-record.

Out of the box, snap works with:

- Wanderlust (Summary buffer)
- Help
- Bookmark
- Man
- Info
- Emacs-wiki
- Navi2ch (Article buffer)
- w3m
- Dired
- text-mode


My modifications to snap include:

- for text-mode and w3m-mode, don't go to the beginning of the line after
  finding the recorded point [default snap behaviour], but stay at the
  point.

- an imperfect but working support for eshell mode: saves the contents of
  an eshell buffer, command-history, and the pwd, allowing some rudimentary
  ability to resume a shell session.


planner-snap.el includes

- planner-snap-annotation-from-buffer(): added to
  planner-annotation-functions

- new planner-protocol: snap


I've also modified remember() in my remember.el so that all context data is
saved when I invoke remember [by running all annotation functions]. This
allows me have a snap URI with a line number, in addition to the usual URI
produced by planner.

(defcustom remember-run-all-annotation-functions t
  "If non-nil every function in `remember-annotation-functions' is
called."
  :type 'boolean
  :group 'remember)

; From http://www.astrogoth.com/~reeses/software/uniq.el
(load "uniq.el")


And, in remember():

  (let* ((annotation (if remember-run-all-annotation-functions
                         (uniq (mapconcat 'funcall
                                    remember-annotation-functions "\n\n"))
                       (run-hook-with-args-until-success
                        'remember-annotation-functions)))
         (buf (get-buffer-create remember-buffer)))



I find this very useful, your mileage may vary.

The code is by no means perfect -- please feel free to modify.

Cheers,

Berkan

PS: because snap uses the "#line-number" format, it doesn't work well with
filenames that contain the '#' character or with URLs that contain an
anchor string.

planner-snap.el
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snap.el.diff
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