bug#17684: 24.4.50; Feature Request -- Vertical Lines to the Left of and Through Characters

[Keith David Bershatsky]

As a feature request, please consider adding the ability to include vertical 
lines to the left of and also through characters.

CAVEAT:  The vertical line plus the character should be equal to only (1) 
`point` -- like a vertical cursor bar and a character to the right.

This new feature has many applications, including, but not limited to:

*  A thin fill column indicator line that can span the vertical length of the 
window / buffer.

*  Thin tab setting indicators in the form of vertical lines for each tab set.  
(This is built-in to Sublime Text.)

*  A visual vertical division between different parts of the same buffer.

*  A thin vertical line (from top to bottom of the window) that tracks the 
cursor position.

See the following stackoverflow thread for a screenshot of how this looks, 
including the workaround / answer to the question:

http://stackoverflow.com/questions/23744237/emacs-how-to-create-a-vertical-strike-through-effect

My workaround shrinks the character to the right so that the visual sentence 
length is not altered.  The vertical bar cursor that is built-in to Emacs can 
sit next to a character without shrinking said character -- so implementation 
of a vertical line to the left of the character would be similar to how the 
cursor presently works.

BONUS:  As a related feature request, please consider adding the ability to 
draw these vertical lines (from top to bottom of the window) virtually 
instantaneously.  Creating these vertical lines in `elisp` when 
`visual-line-mode` is active is extremely time consuming to perform all the 
calculations (up to 0.25 seconds from start to finish) and needs to be done 
with an `idle-timer` so as not to slow down the normal movement of the cursor 
or typing text quickly.  The calculation and placement of overlays can be sped 
up significantly by *not* calculating for `visual-line-mode`, but I am *very* 
fond of that mode.

Thanks,

Keith

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In GNU Emacs 24.4.50.1 (x86_64-apple-darwin10.8.0, NS appkit-1038.36 Version 
10.6.8 (Build 10K549))
 of 2014-06-01 on MP.local
Repository revision: 117215 lekktu@gmail.com-20140601162519-4dacx2w0ak528z2r
Windowing system distributor `Apple', version 10.3.1038
Configured using:
 `configure --with-ns'

Configured features:
ACL LIBXML2 ZLIB

Important settings:
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  lawlist-scroll-bar-mode: t
  lawlist-delete-selection-mode: t
  lawlist-linum-mode: t
  lawlist-visual-line-mode: t
  vr-mode: t
  hr-mode: t
  flyspell-mode: t
  desktop-save-mode: t
  tabbar-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  transient-mark-mode: t

Recent input:
<escape> x h r <return> <escape> x v r <return> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <s-right> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <s-left> <M-right> <M-right> <M-right> <M-right> 
<M-right> <M-right> <M-right> <M-right> <M-right> <M-right> 
<M-right> <M-right> <M-right> <M-right> <M-right> <M-right> 
<s-down> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <up> <s-right> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <M-left> 
<M-left> <M-left> <M-left> s-N r e p o r t s-z s-w 
k <escape> x r e p o r t - e m a <tab> <tab> b u g 
<return>

Recent messages:
Loading mail-mime-setup...done
Updating addresses...done
Type C-c C-x C-z to exit MIME mode, and type C-c C-x ? to get help.
Saving...done
Mark set
Undo...
Undo!
[k]ill or [s]ave draft?
Loading msgdb for 
+/Users/HOME/.0.data/.0.emacs/.0.mail/msgdb/imap/mail.lawlist.com/lawlist/INBOX.Drafts/spool...done
Making completion list...

Load-path shadows:
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/Users/HOME/.0.data/.0.emacs/Emacs_06_01_2014.app/Contents/Resources/lisp/obsolete/pgg-def

Features:
(shadow emacsbug modb-legacy wl-mime mime-edit pgg-parse pccl pccl-20
signature mime-setup mail-mime-setup semi-setup mime-pgp pgg-def
mime-play filename mime-image modb-standard elmo-imap4 disp-table
bbdb-autoloads lawlist-wl wl-demo wl-draft eword-encode wl-template
sendmail elmo-net elmo-cache elmo-map elmo-dop wl-news wl-address
wl-thread wl-folder wl wl-e21 wl-spam wl-action wl-summary wl-refile
wl-util pp elmo-flag elmo-localdir wl-message elmo-mime mmelmo-buffer
mmelmo-imap mime-view mime-conf calist semi-def mmimap mime-parse
mmbuffer mmgeneric elmo-multi elmo-spam elsp-header elsp-generic elmo
elmo-signal wl-highlight wl-vars wl-version elmo-msgdb modb
modb-generic modb-entity luna mime elmo-util emu invisible inv-23 poem
poem-e20 poem-e20_3 eword-decode std11 elmo-date elmo-vars
elmo-version w3m-load mime-w3m w3m browse-url doc-view jka-compr
image-mode w3m-hist w3m-fb bookmark-w3m w3m-ems w3m-ccl ccl
w3m-favicon w3m-image w3m-proc w3m-util smiley gnus-art mm-uu mml2015
mm-view mml-smime smime savehist lawlist-vr-hr lawlist-whitespace
lawlist-github conf-mode log-edit add-log find-lisp package esh-var
esh-io esh-cmd esh-opt esh-ext esh-proc esh-arg eldoc esh-groups
eshell esh-module esh-mode esh-util dired-x view tramp tramp-compat
tramp-loaddefs trampver server grep epa epg epg-config diff-mode
autorevert filenotify log-view pcvs-util ido time-stamp vc-git vc
vc-dispatcher ediff-merg ediff-wind ediff-diff ediff-mult ediff-help
ediff-init ediff-util ediff rx ert ewoc debug eieio-base
lawlist-calculator ps-print ps-def lpr flyspell ispell bbdb timezone
find-func dired-aux lawlist-yasnippet help-mode multiple-cursors
mc-separate-operations rectangular-region-mode mc-mark-more thingatpt
mc-cycle-cursors mc-edit-lines multiple-cursors-core rect saveplace
lawlist-tex-mode pcase compile shell pcomplete comint ansi-color ring
skeleton compare-w desktop frameset lawlist-tabbar lawlist-org
lawlist-calendar edmacro kmacro derived lawlist-toodledo advice
url-http url-auth url-gw url url-proxy url-privacy url-expand
url-methods url-history url-cookie url-domsuf url-util url-parse
auth-source eieio byte-opt bytecomp byte-compile cconv eieio-core
password-cache url-vars mailcap json xml noutline outline easy-mmode
gnus-sum gnus-group gnus-undo gnus-start gnus-cloud nnimap nnmail
mail-source tls utf7 mel path-util mime-def alist mcharset mcs-20
mcs-e20 pcustom pces pces-e20 pces-20 broken poe pym static apel-ver
product netrc nnoo parse-time gnus-spec gnus-int gnus-range message
cl-macs dired format-spec rfc822 mml easymenu mml-sec mm-decode
mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums
mailabbrev gmm-utils mailheader gnus-win gnus gnus-ems nnheader
gnus-util mail-utils mm-util help-fns mail-prsvr wid-edit cl gv
cl-loaddefs cl-lib time-date tooltip electric uniquify ediff-hook
vc-hooks lisp-float-type mwheel ns-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode
register page menu-bar rfn-eshadow timer select scroll-bar mouse
jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
cocoa ns multi-tty emacs)

Memory information:
((conses 16 735058 70571)
 (symbols 48 55594 0)
 (miscs 40 466 1504)
 (strings 32 116283 16738)
 (string-bytes 1 3865036)
 (vectors 16 42190)
 (vector-slots 8 741311 45040)
 (floats 8 1012 256)
 (intervals 56 691 89)
 (buffers 960 14))


Sincerely,

Keith David Bershatsky, Esq.
Law Office of Keith David Bershatsky
1725 Echo Park Avenue
Los Angeles, CA  90026

Tel. / Fax.:  (213) 975-9447
esq@lawlist.com