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#+TAGS:       Write(w) Update(u) Fix(f) Check(c)
#+TITLE:      Org-mode outside Org-mode
#+AUTHOR:     Thorsten Jolitz, François Pinard
#+EMAIL:      tjolitz at gmail dot com
#+DATE:        <2013-03-12 Di>
#+LANGUAGE:   en
#+PRIORITIES: A C B
#+CATEGORY:   worg

[[file:index.org][{Back to Worg's index}]]

* Introduction
  :PROPERTIES:
  :CUSTOM_ID: introduction
  :END:

  Once one gets used to Org-mode, it's hard to live without it. Even its most
  basic feature, the hierarchical tree-like structuring of files, can be
  missed badly when editing files in other GNU Emacs major-modes, not to
  mention the convenient navigation, structure-editing and visibility-cycling
  functionality Org-mode offers for these tree-like structures.

  One especially important case where Org-mode users might miss Org-mode
  functionality is their =.emacs= configuration file. These Emacs Lisp files
  might become huge, for example [[http://www.mygooglest.com/fni/dot-emacs.html][Fabrice Niessen's .emacs]] has some 9720 lines,
  and structuring them only using Emacs Lisp comments (=;=) easily becomes a
  creative nightmare (many approaches for structuring a .emacs file can be
  found on [[http://www.dotemacs.de/index.html][the very unofficial dotemacs home]] page). 

  Another typical case where Org-mode's editing facilities are missing is
  writing the comment-header sections of Emacs Lisp source code files. These
  sections often contain extensive explanations of the development-history,
  installation-process and usage of the library, but are just that - Emacs
  Lisp comment-sections. Sometimes even the comment-strings of important and
  complex Emacs Lisp functions contain long and complicated text parts that
  are not easy to edit as comments. 

  Last not least, anybody who has used =C-c C-j (org-goto)= for looking up a
  different location in the current org-file, keeping current visibility,
  might have wondered if a kind of 'remote-buffer-control' via an associated
  read-only buffer might not be a generally useful idea.

* Org-mode everywhere
  :PROPERTIES:
  :CUSTOM_ID: org-mode-everywhere
  :END:
** File Structuring
   :PROPERTIES:
   :CUSTOM_ID: file-structuring
   :END:
*** Orgstruct 
    :PROPERTIES:
    :CUSTOM_ID: orgstruct-minor-mode
    :END:

   One possibility to enjoy Org-mode's structure-editing and list-formatting
   facilities outside Org-mode buffers is /Orgstruct minor mode/. Let's cite
   from the [[https://orgmode.org/manual/Orgstruct-mode.html][Org-mode manual]]:

#+begin_example
    If you like the intuitive way the Org mode structure editing and list
    formatting works, you might want to use these commands in other modes like
    Text mode or Mail mode as well. The minor mode orgstruct-mode makes this
    possible. [...]

    When this mode is active and the cursor is on a line that looks to Org like a
    headline or the first line of a list item, most structure editing commands
    will work, even if the same keys normally have different functionality in
    the major mode you are using. If the cursor is not in one of those special
    lines, Orgstruct mode lurks silently in the shadows. When you use
    orgstruct++-mode, Org will also export indentation and autofill settings
    into that mode, and detect item context after the first line of an item.
#+end_example

*orgstruct* currently does NOT work with /outorg/ and /navi-mode/ (see below for
a description of these libraries). To make both libraries work with
orgstruct-buffers just like with outshine-buffers, it would be necessary to:

 1. Structure the file with outshine-style headings (e.g. =;; * Header=)
 2. Make Orgstruct calculate and set file-local variable =outline-regexp= the
    way /outshine/ does.
 3. Make Orgstruct calculate and set file-local variable =outline-level= the
    way /outshine/ does.
 4. Make Orgstruct calculate and set file-local variable
    =outline-promotion-headings= the way /outshine/ does. 

Then, maybe after a few minor tweaks in the libraries themselves, /outorg/ and
/navi-mode/ wouldn't care if they deal with an orgstruct-buffer or an
outshine-buffer.

*** Outline with Outshine 
    :PROPERTIES:
    :CUSTOM_ID: outline-with-outshine
    :END:

**** History and Credits
    :PROPERTIES:
    :CUSTOM_ID: history-and-credits
    :END:

*outshine* is a merge and extension of older extensions for
/outline-minor-mode/. More exactly, /outshine/ developed out of the now
obsolete =outxxtra.el=, /Thorsten Jolitz's/ modified extension of /Per
Abrahamsen's/ =out-xtra.el=. With the blessing of it's (well-known) author
/Carsten Dominik/, /Thorsten Jolitz/ could merge the (slightly modified)
=outline-magic.el= with =outxxtra.el= and extend them into the new
=outshine.el= library. Thus, if you use outline with outshine, you don't need
outline-magic and out-xtra anymore. However, outshine does not make either of
these two obsolete libraries, since it has a more specialized approach and
might not be able to replace them in all cases.

Furthermore, `outshine.el' includes functions and keybindings from
[[http://emacswiki.org/emacs/OutlineMinorMode][outline-mode-easy-bindings]]. Unfortunately, no author is given for that
library, so I cannot credit the person who wrote it.

So what is /outshine/? It's an extension library for outline-minor-mode that
gives buffers in different major-modes the 'look-and-feel' of Org-mode buffers
and enables the use of /outorg/ and /navi-mode/ on them.

To sum it up in one sentence:

#+begin_verse
 Outline with Outshine outshines Outline
#+end_verse

**** Installation
     :PROPERTIES:
     :CUSTOM_ID: outshine-installation
     :END:

Download =outshine.el= (or clone the github-repo) and copy it to a location
where Emacs can find it:

| https://github.com/tj64/outshine           |
| git clone git@github.com:tj64/outshine.git |

Use this in your '.emacs' to get started:

#+begin_src emacs-lisp
(require 'outshine)
(add-hook 'outline-minor-mode-hook 'outshine-hook-function)
#+end_src

If you like the functions and keybindings for 'M -<<arrow-key>>' navigation
and visibility cycling copied from `outline-mode-easy-bindings', you might
want to put the following code into your Emacs init file to have the same
functionality/keybindings available in Org-mode too, overriding the less
frequently used commands for moving and promoting/demoting subtrees (but
clashing with 'org-table' keybindings):

#+begin_src emacs-lisp
(when (require 'outshine nil 'NOERROR)
  (add-hook 'org-mode-hook
            (lambda ()
              ;; Redefine arrow keys, since promoting/demoting and moving
              ;; subtrees up and down are less frequent tasks then
              ;; navigation and visibility cycling
                (org-defkey org-mode-map
                            (kbd "M-<left>") 'outline-hide-more)
                (org-defkey org-mode-map
                            (kbd "M-<right>") 'outline-show-more)
                (org-defkey org-mode-map
                            (kbd "M-<up>") 'outline-previous-visible-heading)
                (org-defkey org-mode-map
                            (kbd "M-<down>") 'outline-next-visible-heading))
            'append))
#+end_src

Add this if you (e.g.) always want outline/outshine for emacs-lisp buffers
(recommended):

#+begin_src emacs-lisp
(add-hook 'emacs-lisp-mode-hook 'outline-minor-mode)  
#+end_src

If you want a different prefix key for outline-minor-mode, insert first
(e.g.):

#+begin_src emacs-lisp
 (defvar outline-minor-mode-prefix "\C-c") 
#+end_src

or whatever you like best to replace the (quite unusable) original prefix
"\C-c @". The prefix can only be changed before outline (minor) mode is
loaded.

**** Outshine's fundamental idea
     :PROPERTIES:
     :CUSTOM_ID: fundamental-idea
     :END:

/outshine/ is based on a very simple yet powerful idea, that enables its use
in any Emacs major-mode (in theory at least):

#+begin_verse
Outshine headlines are Org-mode headlines out-commented with =comment-region=
#+end_verse

Thus, the file at hand must be outline-structured 'the outshine way', i.e.
with the headlines being proper Org-mode headlines, marked and outcommented
with =comment-region=. As an example, to generate a 3rd level
outshine-headline in an Emacs Lisp file, write down

: ,-----------------------
: | *** Third Level Header 
: `-----------------------

mark the header line, and apply =comment-region= on it:

: ,-----------------------
: | ;; *** Third Level Header 
: `-----------------------

In a LaTeX file, an adequate header will look like this:

: ,-----------------------
: | % *** Third Level Header 
: `-----------------------

and in a PicoLisp file like this (always depending of the major-mode specific
values of =comment-start=, =comment-end=, =comment-add= and
=comment-padding=):

: ,-----------------------
: | ## *** Third Level Header 
: `-----------------------

=outshine.el=, =outorg.el= and =navi-mode.el= are all examples of how to
structure emacs-lisp source files with outshine-style headlines. 

**** Fontification, Navigation and Structure Editing
     :PROPERTIES:
     :CUSTOM_ID: fontification-navigation-and-structure-editing
     :END:

After structuring a source code file the 'outshine-way' and loading
outline-minor-mode with outshine-extensions, the file will have a very
Org-mode like 'look-and-feel'. The headlines (up to level 8) are fontified the
same way Org-mode headlines are fontified, and the very specific navigation
and structure editing commands of outline-minor-mode as well as their more
general Org-mode style counterparts are available:

=outline-minor-mode= Minor Mode Bindings:

| key       | binding                          |
|-----------+----------------------------------|
| C-c       | PrefixCommand                    |
| <M-down>  | outline-next-visible-heading     |
| <M-left>  | outline-hide-more                |
| <M-right> | outline-show-more                |
| <M-up>    | outline-previous-visible-heading |
| <tab>     | outshine-cycle-subtree           |
| <backtab> | outshine-cycle-buffer            |
| C-c C-a   | show-all                         |
| C-c C-b   | outline-backward-same-level      |
| C-c C-c   | hide-entry                       |
| C-c C-d   | hide-subtree                     |
| C-c C-e   | show-entry                       |
| C-c C-f   | outline-forward-same-level       |
| C-c TAB   | show-children                    |
| C-c C-k   | show-branches                    |
| C-c C-l   | hide-leaves                      |
| C-c RET   | outline-insert-heading           |
| C-c C-n   | outline-next-visible-heading     |
| C-c C-o   | outline-hide-other               |
| C-c C-p   | outline-previous-visible-heading |
| C-c C-q   | outline-hide-sublevels           |
| C-c C-s   | show-subtree                     |
| C-c C-t   | hide-body                        |
| C-c C-u   | outline-up-heading               |
| C-c C-v   | outline-move-subtree-down        |
| C-c C-^   | outline-move-subtree-up          |
| C-c '     | outorg-edit-as-org               |
| C-c @     | outline-mark-subtree             |
| C-c I     | outline-previous-visible-heading |
| C-c J     | outline-hide-more                |
| C-c K     | outline-next-visible-heading     |
| C-c L     | outline-show-more                |
| C-c C-<   | outline-promote                  |
| C-c C->   | outline-demote                   |

** Subtree and Comment Editing
   :PROPERTIES:
   :CUSTOM_ID: comment-editing
   :END:
*** Introduction
    :PROPERTIES:
    :CUSTOM_ID: comment-editing-introduction
    :END:

    Once a (outshine) source code buffer looks and behaves like an Org-mode
    buffer, it would be nice to have the full editing power of Org-mode
    available when editing the (comment) text parts or overall structure of
    the buffer.

    Think "reverse Org-Babel": editing of comment-sections or entire subtrees
    from source code files in temporary Org-mode buffers instead of editing of
    Org-mode source-blocks in temporary source-code buffers.

    There are two new libraries available for editing with Org-mode in other
    major-modes, /outorg/ and /poporg/. Although developed independently with
    very different implementations, both libraries complement each other very
    well in their functionality. 

*** Outorg
    :PROPERTIES:
    :CUSTOM_ID: outorg
    :END:

**** Introduction and Installation
    :PROPERTIES:
    :CUSTOM_ID: outorg-introduction-and-installation
    :END:

*outorg* is a library written by /Thorsten Jolitz/ on top of his /outshine/
library. Thus, /outorg/ needs /outshine/, and files that are structured with
outshine-style headers, otherwise it won't work (note that 'oldschool' Emacs
Lisp files with headers matched by =^;;;+= are a special case where outorg
works too). 

You can download the file (or clone the github-repo) here:

| https://github.com/tj64/outorg           |
| git clone git@github.com:tj64/outorg.git |

/outorg/ requires Org-mode too, thus should be loaded after Org-mode. Insert

#+begin_src emacs-lisp
 (require 'outorg)
#+end_src

in your .emacs and you are done. 

**** Usage
     :PROPERTIES:
     :CUSTOM_ID: outorg-usage
     :END:

/outorg's/ main command is

:  ,---------------------------
:  | C-c ' (outorg-edit-as-org)
:  `---------------------------

used in source-code buffers where `outline-minor-mode' is activated with
`outshine' extensions. The Org-mode edit-buffer popped up by this command
has `outorg-edit-minor-mode' activated, a minor-mode with only 2 commands:

: ,----------------------------------------
: | M-# (outorg-copy-edits-and-exit)
: | C-x C-s (outorg-save-edits-to-tmp-file)
: `----------------------------------------

If you want to insert Org-mode source-code or example blocks in
comment-sections, simply outcomment them in the outorg-edit buffer before
calling `outorg-copy-edits-and-exit'.

Thus, with point inside a subtree or on a subtree header, pressing =C-c '
(outorg-edit-as-org)= will open this subtree in a temporary Org-mode edit
buffer, with all out-commented parts in the original buffer uncommented, and
all source code parts enclosed in Org-mode source blocks. 

When =outorg-edit-as-org= is called with a prefix =C-u=, the whole source-code
buffer will be transformed into Org-mode and offered for editing in a
temporary Org-mode buffer, all headlines folded except the subtree where point
was in.

If the original-buffer was read-only, the user is asked if he wants to make it
writable for the Org-mode editing. If he answers yes, the buffer can be
edited, but will be set back to read-only again after editing is finished.

To avoid accidental loss of edits, the temporary outorg-edit-buffer is backed
up in the OS =/tmp= directory. During editing, the outorg-edit-buffer can be
saved as usual with =save-buffer= via  =C-x C-s=. Even when killed by
accident, that last state of the outorg-edit-buffer will be saved and can be
recovered. 

When done with editing in Org-mode, =M-# (Meta-key and #)= is used to call
=outorg-copy-edits-and-exit=, a command that orderly exits the edit-buffer by
converting the (modified) comment-sections back to comments and extracting the
source-code parts out of the Org-mode source-code blocks.

Please note: /outorg/ is line-based, it only works with 'one-line' comments,
i.e. with comment-sections like those produced by `comment-region' (a command
that comments or uncomments each line in the region). Those special multi-line
comments found in many programming languages are not recognized and lead to
undefined behaviour.

**** Outorg vs Poporg
     :PROPERTIES:
     :CUSTOM_ID: outorg-vs-poporg
     :END:

/outorg/ works on subtrees (or whole buffers). 

One advantage of this is that there is always a complete subtree (-hierarchy)
in the outorg-edit-buffer, thus not only the Orgmode editing functionality can
be applied, but also its export facilities and many other commands that act on
headlines or subtrees. As an example, in order to produce the nice README.txt
files for the github-repos of /outshine/, /outorg/ and /navi-mode/, I simply
called =outorg-edit-as-org= on the first 1st-level-headline of the source-code
files (the file header comment-sections) and exported the subtree to ASCII.

One disadvantage of this is that comment-strings of (e.g. emacs-lips)
functions cannot be edited comfortably, since after transformation of the
source-code buffer they end up inside Org-mode source-code blocks - as
comment-strings, just like before. 

Enters /poporg/. It will be described in much detail in the next section, but
it can already be mentioned here that it does exactly what /outorg/ cannot do
well - Org-mode editing of atomic, isolated comment-strings, no matter where
they are found in the source code buffer. And it is, in contrast to /outorg/,
completely independent from outline structuring with e.g. /outshine/ or
/orgstruct/. 

*** Poporg
    :PROPERTIES:
    :CUSTOM_ID: poporg
    :END:

[NOTE: This section of the tutorial is copied from
[[https://github.com/QBobWatson/poporg]], where you can find the =poporg.el= file too,
and only slightly modified]

**** Introduction
     :PROPERTIES:
     :CUSTOM_ID: poporg-introcuction
     :END:

*poporg* is a small Emacs lisp project written by /François Pinard/ to
help editing program strings and comments using Org mode (or any other
major mode).  This can be useful as it is often more convenient to
edit large pieces of text, like Emacs lisp or Python docstrings, in an
org-mode buffer instead of in a comment or a string.

Emacs does not easily handle multiple major modes in a single buffer.
So far many solutions have been implemented, with varying degrees of
success, but none is perfect.  The *poporg* approach avoids the problem
by extracting the text from the comment or the string from a buffer
using a major programming mode, into a separate buffer to be edited in
a text mode, but containing only that comment or that string.  Once
the edit is completed, the modified comment or string gets
re-integrated in the buffer containing the program, replacing the
original contents.

The main utility of this package is its ability to handle prefixes
automatically.  For comments, it finds all contiguous nonempty
comments on their own line, and strips the common prefix before
inserting into the editing buffer (see =poporg-comment-skip-regexp=).
For strings, it checks if there is consistent indentation for the
whole string (the opening delimiter of the string can only have
whitespace before it), and uses that as the common prefix.  For
regions, it just uses a naive common prefix.  When placing the edited
text back in context, it adds the common prefix again, potentially
stripping any trailing whitespace (see
=poporg-delete-trailing-whitespace=).  It can even adjust the fill
column in the editing buffer to account for indentation (see
=poporg-adjust-fill-column=).

**** Installation
     :PROPERTIES:
     :CUSTOM_ID: poporg-installation
     :END:

To install *poporg*, move file =poporg.el= to a place where Emacs will
find it.  You might byte-compile the file if you want.  There are also
[[https://github.com/dimitri/el-get][El-Get]] and [[http://melpa.milkbox.net/][MELPA]] recipes.

To use *poporg*, you need to pick some unused keybinding and add a few
lines to your =~/.emacs= file, such as:

#+BEGIN_SRC emacs-lisp
  (autoload 'poporg-dwim "poporg" nil t)
  (global-set-key (kbd "C-c \"") 'poporg-dwim)
#+END_SRC

It is important that this be a global keybinding, or at least that the
command =poporg-dwim= be available from both the programming and the
text editing buffers.

**** Usage
     :PROPERTIES:
     :CUSTOM_ID: poporg-usage
     :END:

The command =poporg-dwim= searches for a nearby comment or string (see
=poporg-find-string-or-comment=) and, upon finding one, it opens an
empty buffer in a new window with its contents available for editing.
If the region is active then =poporg-dwim= inserts the region into the
buffer instead.  The original text is grayed out and set read-only to
prevent editing in two places at once.  After editing, running
=poporg-dwim= again from the editing buffer kills the editing buffer and
inserts the edited text back into its original context.

Hopefully =poporg-dwim= will do what you expect in most situations.  It
uses the buffer's syntax table for parsing, so it should adapt well to
most modes (including sextuple-quoted strings in Python).  If you run
=poporg-dwim= in the vicinity of a grayed-out region that you are
editing in another buffer, it pops to that buffer.  It has the
following caveats:

 1. It does not understand empty strings.
 2. It cannot deal very well with comments with ending delimiters.

For example, in c-mode, comments start with =/*= and end with =*/=.  This
is a problem because poporg needs a common prefix for all lines.  In
order to make poporg understand these comments, write them on separate
lines like this:

#+BEGIN_SRC c
 /*
  * Comments go here.  Not on a line with the opening delimiter or the
  * closing delimiter.
  */
#+END_SRC

In this situation poporg will ignore the first and last lines because
they are empty except for comment delimiters, and detect the common
prefix =__= or =__*_= for the middle lines, depending on whether the =*=
character is matched by =poporg-comment-skip-regexp=.

You will probably want to customize =poporg-edit-hook=, since that is
where the major mode of the edit buffer is set.  The minor mode
=poporg-mode= is activated in the edit buffer.  It has one keybinding by
default, which remaps =save-buffer= (C-x C-s) to =poporg-edit-exit=.  You
can add additional keybindings to =poporg-mode-map=.  To save an edit,
from the editing buffer run =poporg-edit-exit= or =poporg-dwim=; to abort
the edit simply kill the buffer.

** Remote Buffer Control
   :PROPERTIES:
   :CUSTOM_ID: remote-buffer-control
   :END:

While visibility-cycling and outline-navigation commands make it very
convenient to work even with big Org-mode or outshine buffers, it can't be
denied that a read-only "twin-buffer" with one-key command-bindings,
exclusively for navigation and high-level structure editing of the associated
original-buffer, can be even more convenient.

Enters /navi-mode/, a major-mode by /Thorsten Jolitz/ derived from and
inspired by /occur-mode/ (and, to a certain extend, the =org-goto= command).
Just like /outorg/, /navi-mode/ depends on /outshine/ and works only with
source-code files structured with 'outshine-style' outline-headers. It does
work with Org-mode files and 'oldschool' Emacs Lisp files too, though. 

A /navi-buffer/ is a kind of "remote-control" for its associated
/original-buffer/. It offers a vast amount of views on the /original-buffer/
via predefined occur-searches that combine headlines and
(programming-language specific) keywords. It further allows many frequent
actions on the subtree at point to be triggered directly from the
/navi-buffer/, without (visibly) switching to the /original-buffer/ where the
actions take place. 

A special feature of /navi-mode/ is its customizability. It predefines all
ASCII printing characters as keybindings for the =navi-generic-command=, and
users can therefore map their user-defined regexp-searches (customizable
variable =navi-keywords=) to any of the many free one-key bindings (in
customizable variable =navi-key-mappings=). These customizations are made by
programming-language, thus the Emacs community could work out default
'alists' for many languages that then may be used and modified by the users. 

/navi-mode's/ author /Thorsten Jolitz/ already worked out two configurations,
one for Emacs Lisp and the other for PicoLisp. You could use them as
inspiration for a configuration of your favorite programming language - and
send these 'alists' to him so that he can include them in the library. The
more predefined sets of keyword searches there are, the easier to use
/navi-mode/ with many languages.

*** Navi-mode
    :PROPERTIES:
    :CUSTOM_ID: navi-mode
    :END:

**** About navi-mode
     :PROPERTIES:
     :CUSTOM_ID: about-navi-mode
     :END:

/navi-mode/ implements extensions for occur-mode. You can think of a
navi-buffer as a kind of 'remote-control' for an (adequately)
outline-structured original-buffer. It enables quick navigation and basic
structure editing in the original-buffer without (necessarily) leaving the
navi-buffer. When switching to the original-buffer and coming back after some
modifications, the navi-buffer is always reverted (thus up-to-date).

Besides the fundamental outline-heading-searches (8 outline-levels) and the 5
basic keyword-searches (:FUN, :VAR, :DB, :OBJ and :ALL), all languages can
have their own set of searches and keybindings (see =navi-key-mappings= and
=navi-keywords=). Heading-searches and keyword-searches can be combined,
offering a vast amount of possible 'views' at the original-buffer.

**** Installation

Download (or clone the github-repos of) the three required libraries

| `navi-mode.el' | https://github.com/tj64/navi           |
|                | git clone git@github.com:tj64/navi.git |
| `outshine.el'  | https://github.com/tj64/outshine       |
| `outorg.el'    | https://github.com/tj64/outorg         |

and put them in a place where Emacs can find them (on the Emacs 'load-path').
Follow the installation instructions in =outshine.el= and =outorg.el=.

Install =navi-mode.el= by adding

#+begin_src emacs-lisp
 (require 'navi-mode)
#+end_src

to your .emacs file. 


**** Usage
     :PROPERTIES:
     :CUSTOM_ID: navi-mode-usage
     :END:

For /navi-mode/ to work, the original-buffer must be outline-structured 'the
outshine way', i.e. with the headlines being proper Org-mode headlines, marked
and outcommented with /comment-region/ (but oldschool Emacs Lisp headers like
=;;; header level 1= work too) . 

The second assumption is that /outline-minor-mode/ is activated in the
original-buffer and /outshine.el/ loaded like described in its installation
instructions (except for Org-mode files). 

When these pre-conditions are fulfilled (/outorg.el/ must be loaded too), you
can use =M-s n (navi-search-and-switch)= to open a /navi-buffer/ and
immediately switch to it. The new navi-buffer will show the first-level
headings of the /original-buffer/, with point at the first entry.

You can then:

 - Show headlines (up-to) different levels:

| key     | command            | function-name        |
|---------+--------------------+----------------------|
| 1 ... 8 | show levels 1 to 8 | navi-generic-command |

 - Navigate up and down in the search results shown in the navi-buffer:

| key | command   | function-name       |
|-----+-----------+---------------------|
| p   | previous  | occur-prev          |
| n   | next      | occur-next          |
| DEL | down page | scroll-down-command |
| SPC | up page   | scroll-up-command   |

 - Revert the navi-buffer (seldom necessary), show help for the user-defined
   keyword-searches, and quit the navi-buffer and switch-back to the
   original-buffer:

| key | command                   | function-name        |
|-----+---------------------------+----------------------|
| g   | revert buffer             | navi-revert-function |
| h   | show help                 | navi-show-help       |
| q   | quit navi-mode and switch | navi-quit-and-switch |

 - Switch to the original-buffer and back to the navi-buffer, display an
   occurrence in the original-buffer or go to the occurrence:

| key     | command                | function-name                     |
|---------+------------------------+-----------------------------------|
| M-s n   | launch navi-buffer     | navi-search-and-switch            |
| M-s s   | switch to other buffer | navi-switch-to-twin-buffer        |
| M-s M-s |                        |                                   |
| s       |                        |                                   |
| d       | display occurrence     | occur-mode-display-occurrence     |
| o       | goto occurrence        | navi-goto-occurrence-other-window |

 - Structure editing on subtrees and visibility cycling

| key       | command                        | function-name          |
|-----------+--------------------------------+------------------------|
| TAB       | cycle subtrees                 | navi-cycle-subtree     |
| <backtab> | cycle buffer                   | navi-cycle-buffer      |
| +         | Demote Subtree                 | navi-demote-subtree    |
| -         | promote subtree                | navi-promote-subtree   |
| \^        | move up subtree (same level)   | navi-move-up-subtree   |
| <         | move down subtree (same level) | navi-move-down-subtree |

 - Miscellaneous actions on subtrees

| key | command                    | function-name                     |
|-----+----------------------------+-----------------------------------|
| m   | mark subtree               | navi-mark-subtree-and-switch      |
| c   | copy subtree               | navi-copy-subtree-to-register-s   |
| k   | kill subtree               | navi-kill-subtree                 |
| y   | yank killed/copied subtree | navi-yank-subtree-from-register-s |
| u   | undo last change           | navi-undo                         |
| r   | narrow to subtree          | navi-narrow-to-subtree            |
| w   | widen                      | navi-widen                        |
| l   | query-replace              | navi-query-replace                |
| i   | isearch                    | navi-isearch                      |
| e   | edit as org (outorg)       | navi-edit-as-org                  |

 - Furthermore, there are five (semantically) predefined keyword-searches:

| key | keyword-symbol | searches for               |
|-----+----------------+----------------------------|
| f   | :FUN           | functions, macros etc.     |
| v   | :VAR           | vars, consts, customs etc. |
| x   | :OBJ           | OOP (classes, methods etc) |
| b   | :DB            | DB (store and select)      |
| a   | :ALL           | all                        |


 - And (potentially) many more user-defined keyword-searches
(example Emacs Lisp):

| key | keyword-symbol | searches for |
|-----+----------------+--------------|
| F   | :defun         | (defun       |
| V   | :defvar        | (defvar      |
| C   | :defconst      | (defconst    |
| G   | :defgroup      | (defgroup    |
| U   | :defcustom     | (defcustom   |
| A   | :defadvice     | (defadvice   |
| M   | :defmacro      | (defmacro    |
| E   | :defface       | (defface     |
| S   | :defstruct     | (defstruct   |
| L   | :defclass      | (defclass    |

 - Headline-searches and keyword-searches can be combined, e.g.

: ,------
: | C-2 f 
: `------

in a /navi-buffer/ associated to an Emacs Lisp source file shows all headlines
up-to level 2 as well as all function, macro and advice definitions in the
original-buffer,

: ,------
: | C-5 a 
: `------

shows all headlines up-to level 5 as well as all functions, variables,
classes, methods, objects, and database-related definitions. The exact meaning
of the standard keyword-searches 'f' and 'a' must be defined with a regexp in
the customizable variable `navi-keywords' (just like the user-defined
keyword-searches).

* Screencasts 
  :PROPERTIES:
  :CUSTOM_ID: screencasts
  :END:

There are some screencasts on Youtube that show the libraries mentioned in
this article in action:

| topic                          | url                            |
|--------------------------------+--------------------------------|
| <30>                           | <30>                           |
| Modern conventions for Emacs Lisp files | https://www.youtube.com/watch?v=nqE6YxlY0rw |
| Exploring Bernt Hansen's Org-mode tutorial with 'navi-mode' | https://www.youtube.com/watch?v=nqE6YxlY0rw |
| Exploring my dot emacs file with 'navi-mode' | https://www.youtube.com/watch?v=nqE6YxlY0rw |
| Exploring a PicoLisp source file with GNU Emacs navi-mode | https://www.youtube.com/watch?v=MYJvQ-5dvK8 |

'Modern conventions for Emacs Lisp files' is probably the video you should
watch first, it explores 'navi-mode.el' itself as an Emacs Lisp library
structured the 'outshine way', and shows the use of outline-minor-mode,
outorg, poporg and navi-mode on such a file. And is has the best background
music.