(eww-render): Set `eww-current-title' back to "".

[emacs.git] / doc / misc / speedbar.texi

\input texinfo   @c -*-texinfo-*-
@setfilename ../../info/speedbar
@settitle Speedbar: File/Tag summarizing utility
@syncodeindex fn cp

@copying
Copyright @copyright{} 1999--2013 Free Software Foundation, Inc.

@quotation
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with the Front-Cover texts being ``A GNU Manual'',
and with the Back-Cover Texts as in (a) below.  A copy of the license
is included in the section entitled ``GNU Free Documentation License''.

(a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
modify this GNU manual.''
@end quotation
@end copying

@dircategory Emacs misc features
@direntry
* Speedbar: (speedbar).         File/Tag summarizing utility.
@end direntry

@titlepage
@sp 10
@center @titlefont{Speedbar}
@sp 2
@center Eric Ludlam
@vskip 0pt plus 1 fill
@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@contents

@node Top
@top Speedbar

Speedbar is a program for Emacs which can be used to summarize
information related to the current buffer.  Its original inspiration
is the `explorer' often used in modern development environments, office
packages, and web browsers.

Speedbar displays a narrow frame in which a tree view is shown.  This
tree view defaults to containing a list of files and directories.  Files
can be `expanded' to list tags inside. Directories can be expanded to
list the files within itself.  Each file or tag can be jumped to
immediately.

Speedbar expands upon `explorer' windows by maintaining context with the
user.  For example, when using the file view, the current buffer's file
is highlighted.  Speedbar also mimics the explorer windows by providing
multiple display modes.  These modes come in two flavors.  Major display
modes remain consistent across buffers, and minor display modes appear
only when a buffer of the applicable type is shown.  This allows
authors of other packages to provide speedbar summaries customized to
the needs of that mode.

Throughout this manual, activities are defined as `clicking on', or
`expanding' items.  Clicking means using @kbd{Mouse-2} on a
button.  Expanding refers to clicking on an expansion button to display
an expanded summary of the entry the expansion button is
on.  @xref{Basic Navigation}.

@ifnottex
@insertcopying
@end ifnottex

@menu
* Introduction::     Basics of speedbar.
* Basic Navigation:: Basics of speedbar common between all modes.
* File Mode::        Summarizing files.
* Buffer Mode::      Summarizing buffers.
* Minor Modes::      Additional minor modes such as Info and RMAIL.
* Customizing::      Changing speedbar behavior.
* Extending::        Extend speedbar for your own project.
* GNU Free Documentation License:: The license for this documentation.
* Index::
@end menu

@node Introduction
@chapter Introduction
@cindex introduction

To start using speedbar use the command @kbd{M-x speedbar RET} or
select it from the @samp{Options->Show/Hide} sub-menu.  This command
will open a new frame to summarize the local files.  On X Window
systems or on MS-Windows, speedbar's frame is twenty characters wide,
and will mimic the height of the frame from which it was started.  It
positions itself to the left or right of the frame you started it
from.

To use speedbar effectively, it is important to understand its
relationship with the frame you started it from.  This frame is the
@dfn{attached frame} which speedbar will use as a reference point.  Once
started, speedbar watches the contents of this frame, and attempts to
make its contents relevant to the buffer loaded into the attached
frame.  In addition, all requests made in speedbar that require the
display of another buffer will display in the attached frame.

When used in terminal mode, the new frame appears the same size as the
terminal.  Since it is not visible while working in the attached frame,
speedbar will save time by using the @dfn{slowbar mode}, where no tracking is
done until speedbar is requested to show itself (i.e., the speedbar's
frame becomes the selected frame).

@cindex @code{speedbar-get-focus}
The function to use when switching between frames using the keyboard is
@code{speedbar-get-focus}.  This function will toggle between frames, and
it's useful to bind it to a key in terminal mode.  @xref{Customizing}.

@node Basic Navigation
@chapter Basic Navigation

Speedbar can display different types of data, and has several display
and behavior modes.  These modes all have a common behavior, menu
system, and look.  If one mode is learned, then the other modes are easy
to use.

@menu
* Basic Key Bindings::
* Basic Visuals::
* Mouse Bindings::
* Displays Submenu::
@end menu

@node Basic Key Bindings
@section Basic Key Bindings
@cindex key bindings

These key bindings are common across all modes:

@table @kbd
@item Q
@cindex quitting speedbar
Quit speedbar, and kill the frame.
@item q
Quit speedbar, and hide the frame.  This makes it faster to restore the
speedbar frame, than if you press @kbd{Q}.
@item g
@cindex refresh speedbar display
Refresh whatever contents are in speedbar.
@item t
@cindex slowbar mode
Toggle speedbar to and from slowbar mode.  In slowbar mode, frame
tracking is not done.
@item n
@itemx p
@cindex navigation
Move, respectively, to the next or previous item.  A summary of that
item will be displayed in the attached frame's minibuffer.
@item M-n
@itemx M-p
Move to the next or previous item in a restricted fashion.  If a list is
open, the cursor will skip over it.  If the cursor is in an open list,
it will not leave it.
@item C-M-n
@itemx C-M-p
Move forwards and backwards across extended groups.  This lets you
quickly skip over all files, directories, or other common sub-items at
the same current depth.
@item C-x b
Switch buffers in the attached frame.
@end table

Speedbar can handle multiple modes.  Two are provided by default.
These modes are File mode, and Buffers mode.  There are accelerators to
switch into these different modes.

@cindex mode switching hotkeys
@table @kbd
@item b
Switch into Quick Buffers mode (@pxref{Buffer Mode}).  After one use, the
previous display mode is restored.
@item f
Switch into File mode.
@item r
Switch back to the previous mode.
@end table

Some modes provide groups, lists and tags.  @xref{Basic Visuals}.  When
these are available, some additional common bindings are available.

@cindex common keys
@table @kbd
@item RET
@itemx e
Edit/Open the current group or tag.  This behavior is dependent on the
mode.  In general, files or buffers are opened in the attached frame,
and directories or group nodes are expanded locally.
@item +
@itemx =
Expand the current group, displaying sub items.
When used with a prefix argument, any data that may have been cached is
flushed.  This is similar to a power click.  @xref{Mouse Bindings}.
@item -
Contract the current group, hiding sub items.
@end table

@node Basic Visuals
@section Basic Visuals
@cindex visuals

Speedbar has visual cues for indicating different types of data.  These
cues are used consistently across the different speedbar modes to make
them easier to interpret.

At a high level, in File mode, there are directory buttons, sub
directory buttons, file buttons, tag buttons, and expansion buttons.
This makes it easy to use the mouse to navigate a directory tree, and
quickly view files, or a summary of those files.

The most basic visual effect used to distinguish between these button
types is color and mouse highlighting.  Anything the mouse highlights
can be clicked on and is called a button (@pxref{Mouse Bindings}).
Anything not highlighted by the mouse will not be clickable.

Text in speedbar consists of four different types of data.  Knowing how
to read these textual elements will make it easier to navigate by
identifying the types of data available.

@subsection Groups
@cindex groups

Groups summarize information in a single line, and provide a high level
view of more complex systems, like a directory tree, or manual chapters.

Groups appear at different indentation levels, and are prefixed with a
@samp{+} in some sort of `box'.  The group name will summarize the
information within it, and the expansion box will display that
information inline.  In File mode, directories and files are `groups'
where the @samp{+} is surrounded by brackets like this:

@example
<+> include
<-> src
 [+] foo.c
@end example

In this example, we see both open and closed directories, in addition to
a file.  The directories have a box consisting of angle brackets, and a
file uses square brackets.

In all modes, a group can be `edited' by pressing @kbd{RET}, meaning a
file will be opened, or a directory explicitly opened in speedbar.  A
group can be expanded or contracted using @kbd{+} or
@kbd{-}.  @xref{Basic Key Bindings}.

Sometimes groups may have a @samp{?} in its indicator box.  This means
that it is a group type, but there are no contents, or no known way of
extracting contents of that group.

When a group has been expanded, the indicator button changes from
@samp{+} to @samp{-}.  This indicates that the contents are being shown.
Click the @samp{-} button to contract the group, or hide the contents
currently displayed.

@subsubsection Tags
@cindex tags

Tags are the leaf nodes of the tree system.  Tags are generally prefixed
with a simple character, such as @samp{>}.  Tags can only be jumped to using
@kbd{RET} or @kbd{e}.

@subsubsection Boolean Flags

Sometimes a group or tag is given a boolean flag.  These flags appear as
extra text characters at the end of the line.  File mode uses boolean
flags, such as a @samp{*} to indicate that a file has been checked out
of a versioning system.

For additional flags, see
@c Note to self, update these to sub-nodes which are more relevant.
@ref{File Mode}, and @ref{Version Control}.

@subsubsection Unadorned Text

Unadorned text generally starts in column 0, without any special symbols
prefixing them.  In Buffers mode different buffer groups are prefixed
with a description of what the following buffers are (Files, scratch
buffers, and invisible buffers.)

Unadorned text will generally be colorless, and not clickable.

@subsubsection Color Cues

Each type of Group, item indicator, and label is given a different
color.  The colors chosen are dependent on whether the background color
is light or dark.
Of important note is that the `current item', which may be a buffer or
file name, is highlighted red, and underlined.

Colors can be customized from the group @code{speedbar-faces}.  Some
modes, such as for Info, will use the Info colors instead of default
speedbar colors as an indication of what is currently being displayed.

The face naming convention mirrors the File display mode.  Modes which
do not use files will attempt to use the same colors on analogous
entries.

@node Mouse Bindings
@section Mouse Bindings
@cindex mouse bindings

The mouse has become a common information navigation tool.  Speedbar
will use the mouse to navigate file systems, buffer lists, and other
data.  The different textual cues provide buttons which can be clicked
on (@pxref{Basic Visuals}).  Anything that highlights can be clicked on
with the mouse, or affected by the menu.

The mouse bindings are:

@table @kbd
@item Mouse-1
Move cursor to that location.
@item Mouse-2
@itemx Double-Mouse-1
Activate the current button.  @kbd{Double-Mouse-1} is called a @dfn{double
click} on other platforms, and is useful for windows users with two
button mice.
@c Isn't it true that with two-button mice, the right button is Mouse-2?
@c On GNU/Linux, the right button is Mouse-3.
@item S-Mouse-2
@itemx S-Double-Mouse-1
@cindex power click
This has the same effect as @kbd{Mouse-2}, except it is called a power
click.  This means that if a group with an expansion button @samp{+} is
clicked, any caches are flushed, and subitems re-read.  If it is a name,
it will be opened in a new frame.
@item Mouse-3
Activate the speedbar menu.  The item selected affects the line clicked,
not the line where the cursor was.
@item Mouse-1 @r{(mode line)}
Activate the menu.  This affects the item the cursor is on before the
click, since the mouse was not clicked on anything.
@item C-Mouse-1
Buffers sub-menu.  The buffer in the attached frame is switched.
@end table

When the mouse moves over buttons in speedbar, details of that item
should be displayed in the minibuffer of the attached frame.  Sometimes
this can contain extra information such as file permissions, or tag
location.

@node Displays Submenu
@section Displays Submenu
@cindex displays submenu

You can display different data by using different display modes.  These
specialized modes make it easier to navigate the relevant pieces of
information, such as files and directories, or buffers.

In the main menu, found by clicking @kbd{Mouse-3}, there is a submenu
labeled @samp{Displays}.  This submenu lets you easily choose between
different display modes.

The contents are modes currently loaded into emacs.  By default, this
would include Files, Quick Buffers, and Buffers.  Other major display
modes such as Info are loaded separately.

@node File Mode
@chapter File Mode
@cindex file mode

File mode displays a summary of your current directory.  You can display
files in the attached frame, or summarize the tags found in files.  You
can even see if a file is checked out of a version control system, or
has some associated object file.

Advanced behavior, like copying and renaming files, is also provided.

@menu
* Directory Display::   What the display means.
* Hidden Files::        How to display hidden files.
* File Key Bindings::   Performing file operations.
@end menu

@node Directory Display
@section Directory Display
@cindex directory display

There are three major sections in the display.  The first line or two is
the root directory speedbar is currently viewing.  You can jump to one
of the parent directories by clicking on the name of the directory you
wish to jump to.

Next, directories are listed.  A directory starts with the group
indicator button @samp{<+>}.  Clicking the directory name makes speedbar
load that directory as the root directory for its display.  Clicking the
@samp{<+>} button will list all directories and files beneath.

Next, files are listed.  Files start with the group indicator @samp{[+]}
or @samp{[?]}.  You can jump to a file in the attached frame by clicking
on the file name.  You can expand a file and look at its tags by
clicking on the @samp{[+]} symbol near the file name.

A typical session might look like this:

@example
~/lisp/
<+> checkdoc
<+> eieio
<-> speedbar
 [+] Makefile
 [+] rpm.el #
 [+] sb-gud.el #
 [+] sb-info.el #
 [+] sb-rmail.el #
 [+] sb-w3.el
 [-] speedbar.el *!
  @{+@} Types
  @{+@} Variables
  @{+@} def (group)
  @{+@} speedbar-
 [+] speedbar.texi *
<+> testme
[+] align.el
[+] autoconf.el
@end example

In this example, you can see several directories.  The directory
@file{speedbar} has been opened inline.  Inside the directory
@file{speedbar}, the file @file{speedbar.el} has its tags exposed.
These tags are extensive, and they are summarized into tag groups.

Files get additional boolean flags associated with them.  Valid flags are:

@cindex file flags
@table @code
@item *
This file has been checked out of a version control
system.  @xref{Version Control}.
@cindex @code{speedbar-obj-alist}
@item #
This file has an up to date object file associated with it.  The
variable @code{speedbar-obj-alist} defines how speedbar determines this
value.
@item !
This file has an out of date object file associated with it.
@end table

A Tag group is prefixed with the symbol @samp{@{+@}}.  Clicking this
symbol will show all symbols that have been organized into that group.
Different types of files have unique tagging methods as defined by their
major mode.  Tags are generated with either the @code{imenu} package, or
through the @code{etags} interface.

Tag groups are defined in multiple ways which make it easier to find the
tag you are looking for.  Imenu keywords explicitly create groups, and
speedbar will automatically create groups if tag lists are too long.

In our example, Imenu created the groups @samp{Types} and
@samp{Variables}.  All remaining top-level symbols are then regrouped
based on the variable @code{speedbar-tag-hierarchy-method}.  The
subgroups @samp{def} and @samp{speedbar-} are groupings where the first
few characters of the given symbols are specified in the group name.
Some group names may say something like @samp{speedbar-t to speedbar-v},
indicating that all symbols which alphabetically fall between those
categories are included in that sub-group.  @xref{Tag Hierarchy Methods}.

@node Hidden Files
@section Hidden Files
@cindex hidden files

On GNU and Unix systems, a hidden file is a file whose name starts
with a period.  They are hidden from a regular directory listing
because the user is not generally interested in them.

In speedbar, a hidden file is a file which isn't very interesting and
might prove distracting to the user.  Any uninteresting files are
removed from the File display.  There are two levels of uninterest in
speedbar.  The first level of uninterest are files which have no
expansion method, or way of extracting tags.  The second level is any
file that matches the same pattern used for completion in
@code{find-file}.  This is derived from the variable
@code{completion-ignored-extensions}.

You can toggle the display of uninteresting files from the toggle menu
item @samp{Show All Files}.  This will display all level one hidden files.
These files will be shown with a @samp{?} indicator.  Level 2 hidden
files will still not be shown.

Object files fall into the category of level 2 hidden files.  You can
determine their presence by the @samp{#} and @samp{!} file indicators.
@xref{Directory Display}.

@node File Key Bindings
@section File Key Bindings
@cindex file key bindings

File mode has key bindings permitting different file system operations
such as copy or rename.  These commands all operate on the @dfn{current
file}.  In this case, the current file is the file at point, or clicked
on when pulling up the menu.

@table @kbd
@item U
Move the entire speedbar display up one directory.
@item I
Display information in the minibuffer about this line.  This is the same
information shown when navigating with @kbd{n} and @kbd{p}, or moving
the mouse over an item.
@item B
Byte compile the Emacs Lisp file on this line.
@item L
Load the Emacs Lisp file on this line.  If a @file{.elc} file exists,
optionally load that.
@item C
Copy the current file to some other location.
@item R
Rename the current file, possibly moving it to some other location.
@item D
Delete the current file.
@item O
Delete the current file's object file.  Use the symbols @samp{#} and
@samp{!} to determine if there is an object file available.
@end table

One menu item toggles the display of all available files.  By default,
only files which Emacs understands, and knows how to convert into a tag
list, are shown.  By showing all files, additional files such as text files are
also displayed, but they are prefixed with the @samp{[?]} symbol.  This
means that it is a file, but Emacs doesn't know how to expand it.

@node Buffer Mode
@chapter Buffer Mode
@cindex buffer mode

Buffer mode is very similar to File mode, except that instead of
tracking the current directory and all files available there, the
current list of Emacs buffers is shown.

These buffers can have their tags expanded in the same way as files,
and uses the same unknown file indicator (@pxref{File Mode}).

Buffer mode does not have file operation bindings, but the following
buffer specific key bindings are available:

@table @kbd
@item k
Kill this buffer.  Do not touch its file.
@item r
Revert this buffer, reloading from disk.
@end table

In addition to Buffer mode, there is also Quick Buffer mode.  In fact,
Quick Buffers is bound to the @kbd{b} key.  The only difference between
Buffers and Quick Buffers is that after one operation  is performed
which affects the attached frame, the display is immediately reverted to
the last displayed mode.

Thus, if you are in File mode, and you need quick access to a buffer,
press @kbd{b}, click on the buffer you want, and speedbar will revert
back to File mode.

@node Minor Modes
@chapter Minor Display Modes
@cindex minor display modes

For some buffers, a list of files and tags makes no sense.  This could
be because files are not currently in reference (such as web pages), or
that the files you might be interested have special properties (such as
email folders.)

In these cases, a minor display mode is needed.  A minor display mode
will override any major display mode currently being displayed for the
duration of the specialized buffer's use.  Minor display modes
will follow the general rules of their major counterparts in terms of
key bindings and visuals, but will have specialized behaviors.

@menu
* RMAIL::  Managing folders.
* Info::   Browsing topics.
* GDB::    Watching expressions or managing the current
            stack trace.
@end menu

@node RMAIL
@section RMAIL
@cindex RMAIL

When using RMAIL, speedbar will display two sections.  The first is a
layer one reply button.  Clicking here will initialize a reply buffer
showing only this email address in the @samp{To:} field.

The second section lists all RMAIL folders in the same directory as your
main RMAIL folder.  The general rule is that RMAIL folders always appear
in all caps, or numbers.  It is possible to save mail in folders with
lower case letters, but there is no clean way of detecting such RMAIL folders
without opening them all.

Each folder can be visited by clicking the name.  You can move mail from
the current RMAIL folder into a different folder by clicking the
@samp{<M>} button.  The @samp{M} stands for Move.

In this way you can manage your existing RMAIL folders fairly easily
using the mouse.

@node Info
@section Info
@cindex Info

When browsing Info files, all local relevant information is displayed in
the info buffer and a topical high-level view is provided in speedbar.
All top-level info nodes are shown in the speedbar frame, and can be
jumped to by clicking the name.

You can open these nodes with the @samp{[+]} button to see what sub-topics
are available.  Since these sub-topics are not examined until you click
the @samp{[+]} button, sometimes a @samp{[?]} will appear when you click on
a @samp{[+]}, indicating that there are no sub-topics.

@node GDB
@section GDB
@cindex gdb
@cindex gud

You can debug an application with GDB in Emacs using graphical mode or
text command mode (@pxref{GDB Graphical Interface,,, emacs, The
extensible self-documenting text editor}).

If you are using graphical mode you can see how selected variables
change each time your program stops (@pxref{Watch Expressions,,,
emacs, The extensible self-documenting text editor}).

If you are using text command mode, speedbar can show
you the current stack when the current buffer is the @file{*gdb*}
buffer.  Usually, it will just report that there is no stack, but when
the application is stopped, the current stack will be shown.

You can click on any stack element and gdb will move to that stack
level.  You can then check variables local to that level at the GDB
prompt.

@node Customizing
@chapter Customizing
@cindex customizing

Speedbar is highly customizable, with a plethora of control elements.
Since speedbar is so visual and reduces so much information, this is an
important aspect of its behavior.

In general, there are three custom groups you can use to quickly modify
speedbar's behavior.

@table @code
@item speedbar
Basic speedbar behaviors.
@item speedbar-vc
Customizations regarding version control handling.
@item speedbar-faces
Customize speedbar's many colors and fonts.
@end table

@menu
* Frames and Faces::        Visible behaviors.
* Tag Hierarchy Methods::   Customizing how tags are displayed.
* Version Control::         Adding new VC detection modes.
* Hooks::                   The many hooks you can use.
@end menu

@node Frames and Faces
@section Frames and Faces
@cindex faces
@cindex frame parameters

There are several faces speedbar generates to provide a consistent
color scheme across display types.  You can customize these faces using
your favorite method.  They are:

@table @asis
@cindex @code{speedbar-button-face}
@item speedbar-button-face
Face used on expand/contract buttons.
@cindex @code{speedbar-file-face}
@item speedbar-file-face
Face used on Files.  Should also be used on non-directory like nodes.
@cindex @code{speedbar-directory-face}
@item speedbar-directory-face
Face used for directories, or nodes which consist of groups of other nodes.
@cindex @code{speedbar-tag-face}
@item speedbar-tag-face
Face used for tags in a file, or for leaf items.
@cindex @code{speedbar-selected-face}
@item speedbar-selected-face
Face used to highlight the selected item.  This would be the current
file being edited.
@cindex @code{speedbar-highlight-face}
@item speedbar-highlight-face
Face used when the mouse passes over a button.
@end table

You can also customize speedbar's initial frame parameters.  How this is
accomplished is dependent on your platform being Emacs or XEmacs.

@cindex @code{speedbar-frame-parameters}, Emacs
In Emacs, change the alist @code{speedbar-frame-parameters}.  This
variable is used to set up initial details.  Height is also
automatically added when speedbar is created, though you can override
it.

@cindex @code{speedbar-frame-plist}, XEmacs
In XEmacs, change the plist @code{speedbar-frame-plist}.  This is the
XEmacs way of doing the same thing.

@node Tag Hierarchy Methods
@section Tag Hierarchy Methods
@cindex tag hierarchy
@cindex tag groups
@cindex tag sorting

When listing tags within a file, it is possible to get an annoyingly
long list of entries.  Imenu (which generates the tag list in Emacs)
will group some classes of items automatically.   Even here, however,
some tag groups can be quite large.

@cindex @code{speedbar-tag-hierarchy-method}
To solve this problem, tags can be grouped into logical units through a
hierarchy processor.  The specific variable to use is
@code{speedbar-tag-hierarchy-method}.  There are several methods that
can be applied in any order.  They are:

@table @code
@cindex @code{speedbar-trim-words-tag-hierarchy}
@item speedbar-trim-words-tag-hierarchy
Find a common prefix for all elements of a group, and trim it off.
@cindex @code{speedbar-prefix-group-tag-hierarchy}
@item speedbar-prefix-group-tag-hierarchy
If a group is too large, place sets of tags into bins based on common
prefixes.
@cindex @code{speedbar-simple-group-tag-hierarchy}
@item speedbar-simple-group-tag-hierarchy
Take all items in the top level list not in a group, and stick them into
a @samp{Tags} group.
@cindex @code{speedbar-sort-tag-hierarchy}
@item speedbar-sort-tag-hierarchy
Sort all items, leaving groups on top.
@end table

You can also add your own functions to reorganize tags as you see fit.

Some other control variables are:

@table @code
@cindex @code{speedbar-tag-group-name-minimum-length}
@item speedbar-tag-group-name-minimum-length
Default value: 4.

The minimum length of a prefix group name before expanding.  Thus, if
the @code{speedbar-tag-hierarchy-method} includes
@code{speedbar-prefix-group-tag-hierarchy} and one such group's common
characters is less than this number of characters, then the group name
will be changed to the form of:

@example
worda to wordb
@end example

instead of just

@example
word
@end example

This way we won't get silly looking listings.

@cindex @code{speedbar-tag-split-minimum-length}
@item speedbar-tag-split-minimum-length
Default value: 20.

Minimum length before we stop trying to create sub-lists in tags.
This is used by all tag-hierarchy methods that break large lists into
sub-lists.

@cindex @code{speedbar-tag-regroup-maximum-length}
@item speedbar-tag-regroup-maximum-length
Default value: 10.

Maximum length of submenus that are regrouped.
If the regrouping option is used, then if two or more short subgroups
are next to each other, then they are combined until this number of
items is reached.
@end table

@node Version Control
@section Version Control
@cindex version control
@cindex vc extensions

When using the file mode in speedbar, information regarding a version
control system adds small details to the display.  If a file is in a
version control system, and is ``checked out'' or ``locked'' locally, an
asterisk @samp{*} appears at the end of the file name.  In addition,
the directory name for Version Control systems are left out of the
speedbar display.

@cindex @code{speedbar-directory-unshown-regexp}
You can easily add new version control systems into speedbar's detection
scheme.  To make a directory ``disappear'' from the list, use the variable
@code{speedbar-directory-unshown-regexp}.

@cindex @code{speedbar-vc-path-enable-hook}
Next, you need to write entries for two hooks.  The first is
@code{speedbar-vc-path-enable-hook} which will enable a VC check in the
current directory for the group of files being checked.  Your hook
function should take one parameter (the directory to check) and return
@code{t} if your VC method is in control here.

@cindex @code{speedbar-vc-in-control-hook}
The second function is @code{speedbar-vc-in-control-hook}.  This hook
takes two parameters, the @var{path} of the file to check, and the
@var{file} name.  Return @code{t} if you want to have the asterisk
placed near this file.

@cindex @code{speedbar-vc-indicator}
Lastly, you can change the VC indicator using the variable
@code{speedbar-vc-indicator}, and specify a single character string.

@node Hooks
@section Hooks
@cindex hooks

There are several hooks in speedbar allowing custom behaviors to be
added.  Available hooks are:

@table @code
@cindex @code{speedbar-visiting-file-hook}
@item speedbar-visiting-file-hook
Hooks run when speedbar visits a file in the selected frame.
@cindex @code{speedbar-visiting-tag-hook}
@item speedbar-visiting-tag-hook
Hooks run when speedbar visits a tag in the selected frame.
@cindex @code{speedbar-load-hook}
@item speedbar-load-hook
Hooks run when speedbar is loaded.
@cindex @code{speedbar-reconfigure-keymaps-hook}
@item speedbar-reconfigure-keymaps-hook
Hooks run when the keymaps are regenerated.  Keymaps are reconfigured
whenever modes change.  This will let you add custom key bindings.
@cindex @code{speedbar-before-popup-hook}
@item speedbar-before-popup-hook
Hooks called before popping up the speedbar frame.
New frames are often popped up when ``power clicking'' on an item to view
it.
@cindex @code{speedbar-before-delete-hook}
@item speedbar-before-delete-hook
Hooks called before deleting or hiding the speedbar frame.
@cindex @code{speedbar-mode-hook}
@item speedbar-mode-hook
Hooks called after creating a speedbar buffer.
@cindex @code{speedbar-timer-hook}
@item speedbar-timer-hook
Hooks called after running the speedbar timer function.
@cindex @code{speedbar-scanner-reset-hook}
@item speedbar-scanner-reset-hook
Hook called whenever generic scanners are reset.
Set this to implement your own scanning or rescan safe functions with
state data.
@end table

@node Extending
@chapter Extending
@cindex extending

Speedbar can run different types of Major display modes such as Files
(@pxref{File Mode}), and Buffers (@pxref{Buffer Mode}).  It can also manage
different minor display modes for use with buffers handling specialized
data.

These major and minor display modes are handled through an extension
system which permits specialized keymaps and menu extensions, in
addition to a unique rendering function.  You can also specify a wide
range of tagging functions.  The default uses @code{imenu}, but new
tagging methods can be easily added.  In this chapter, you will
learn how to write your own major or minor display modes, and how to
create specialized tagging functions.

@menu
* Minor Display Modes::    How to create a minor display mode.
* Major Display Modes::    How to create a major display mode.
* Tagging Extensions::     How to create your own tagging methods.
* Creating a display::     How to insert buttons and hierarchies.
@end menu

@node Minor Display Modes
@section Minor Display Modes
@cindex create minor display mode

A @dfn{minor display mode} is a mode useful when using a specific type of
buffer.  This mode might not be useful for any other kind of data or
mode, or may just be more useful that a files or buffers based mode when
working with a specialized mode.

Examples that already exist for speedbar include RMAIL, Info, and gdb.
These modes display information specific to the major mode shown in the
attached frame.

To enable a minor display mode in your favorite Major mode, follow these
steps.  The string @samp{@var{name}} is the name of the major mode being
augmented with speedbar.

@enumerate
@item
Create the keymap variable @code{@var{name}-speedbar-key-map}.

@item
Create a function, named whatever you like, which assigns values into your
keymap.  Use this command to create the keymap before assigning
bindings:

@smallexample
    (setq @var{name}-speedbar-key-map (speedbar-make-specialized-keymap))
@end smallexample

This function creates a special keymap for use in speedbar.

@item
Call your install function, or assign it to a hook like this:

@smallexample
(if (featurep 'speedbar)
    (@var{name}-install-speedbar-variables)
  (add-hook 'speedbar-load-hook '@var{name}-install-speedbar-variables))
@end smallexample

@item
Create an easymenu compatible vector named
@code{@var{name}-speedbar-menu-items}.  This will be spliced into
speedbar's control menu.

@item
Create a function called @code{@var{name}-speedbar-buttons}.  This function
should take one variable, which is the buffer for which it will create
buttons.   At this time @code{(current-buffer)} will point to the
uncleared speedbar buffer.
@end enumerate

When writing @code{@var{name}-speedbar-buttons}, the first thing you will
want to do is execute a check to see if you need to re-create your
display.  If it needs to be cleared, you need to erase the speedbar
buffer yourself, and start drawing buttons.  @xref{Creating a display}.

@node Major Display Modes
@section Major Display Modes
@cindex create major display mode

Creating a @dfn{Major Display Mode} for speedbar requires authoring a keymap,
an easy-menu segment, and writing several functions.  These items can be
given any name, and are made the same way as in a minor display mode
(@pxref{Minor Display Modes}).  Once this is done, these items need to be
registered.

Because this setup activity may or may not have speedbar available when
it is being loaded, it is necessary to create an install function.  This
function should create and initialize the keymap, and add your
expansions into the customization tables.

@cindex @code{speedbar-make-specialized-keymap}
When creating the keymap, use the function
@code{speedbar-make-specialized-keymap} instead of other keymap making
functions.  This will provide you with the initial bindings needed.
Some common speedbar functions you might want to bind are:

@table @code
@cindex @code{speedbar-edit-line}
@item speedbar-edit-line
Edit the item on the current line.
@cindex @code{speedbar-expand-line}
@item speedbar-expand-line
Expand the item under the cursor.
With a numeric argument (@kbd{C-u}), flush cached data before expanding.
@cindex @code{speedbar-contract-line}
@item speedbar-contract-line
Contract the item under the cursor.
@end table

@cindex @code{speedbar-line-path}
These function require that function @code{speedbar-line-path} be
correctly overloaded to work.

Next, register your extension like this;

@example
  (speedbar-add-expansion-list '("MyExtension"
                                 MyExtension-speedbar-menu-items
                                 MyExtension-speedbar-key-map
                                 MyExtension-speedbar-buttons))
@end example

There are no limitations to the names you use.

The first parameter is the string representing your display mode.
The second parameter is a variable name containing an easymenu compatible
menu definition.  This will be stuck in the middle of speedbar's menu.
The third parameter is the variable name containing the keymap we
discussed earlier.
The last parameter is a function which draws buttons for your mode.
This function must take two parameters.  The directory currently being
displayed, and the depth at which you should start rendering buttons.
The function will then draw (starting at the current cursor position)
any buttons deemed necessary based on the input parameters.
@xref{Creating a display}.

Next, you need to register function overrides.  This may look something
like this:

@example
(speedbar-add-mode-functions-list
 '("MYEXTENSION"
   (speedbar-item-info . MyExtension-speedbar-item-info)
   (speedbar-line-path . MyExtension-speedbar-line-path)))
@end example

The first element in the list is the name of you extension.  The second
is an alist of functions to overload.  The function to overload is
first, followed by what you want called instead.

For @code{speedbar-line-path} your function should take an optional DEPTH
parameter.  This is the starting depth for heavily indented lines.  If
it is not provided, you can derive it like this:

@example
(save-match-data
  (if (not depth)
      (progn
        (beginning-of-line)
        (looking-at "^\\([0-9]+\\):")
        (setq depth (string-to-int (match-string 1)))))
@end example

@noindent
where the depth is stored as invisible text at the beginning of each
line.

The path returned should be the full path name of the file associated
with that line.  If the cursor is on a tag, then the file containing
that tag should be returned.  This is critical for built in file based
functions to work (meaning less code for you to write).  If your display
does not deal in files, you do not need to overload this function.

@cindex @code{speedbar-item-info}
The function @code{speedbar-item-info}, however, is very likely to need
overloading.  This function takes no parameters and must derive a text
summary to display in the minibuffer.

There are several helper functions you can use if you are going to use
built in tagging.  These functions can be @code{or}ed since each one
returns non-@code{nil} if it displays a message.  They are:

@table @code
@cindex @code{speedbar-item-info-file-helper}
@item speedbar-item-info-file-helper
This takes an optional @var{filename} parameter.  You can derive your own
filename, or it will derive it using a (possibly overloaded) function
@code{speedbar-line-file}.  It shows details about a file.
@cindex @code{speedbar-item-info-tag-helper}
@item speedbar-item-info-tag-helper
If the current line is a tag, then display information about that tag,
such as its parent file, and location.
@end table

Your custom function might look like this:

@example
(defun MyExtension-item-info ()
  "Display information about the current line."
  (or (speedbar-item-info-tag-helper)
      (message "Interesting detail.")))
@end example

Once you have done all this, speedbar will show an entry in the
@samp{Displays} menu declaring that your extension is available.

@node Tagging Extensions
@section Tagging Extensions

It is possible to create new methods for tagging files in speedbar.
To do this, you need two basic functions, one function to fetch the
tags from a buffer, the other to insert them below the filename.

@defun my-fetch-dynamic-tags file
Parse @var{file} for a list of tags.  Return the list, or @code{t} if there was
an error.
@end defun

The non-error return value can be anything, as long as it can be
inserted by its paired function:

@defun my-insert-tag-list level lst
Insert a list of tags @var{lst} started at indentation level
@var{level}.  Creates buttons for each tag, and provides any other
display information required.
@end  defun

@cindex @code{speedbar-create-tag-hierarchy}
It is often useful to use @code{speedbar-create-tag-hierarchy} on your
token list.  See that function's documentation for details on what it
requires.

@cindex @code{speedbar-dynamic-tags-function-list}
Once these two functions are written, modify the variable
@code{speedbar-dynamic-tags-function-list} to include your parser at the
beginning, like this:

@example
(add-to-list 'speedbar-dynamic-tags-function-list
             '(my-fetch-dynamic-tags . my-insert-tag-list))
@end example

If your parser is only good for a few types of files, make sure that it
is either a buffer local modification, or that the tag generator returns
@code{t} for non valid buffers.

@node Creating a display
@section Creating a display
@cindex creating a display

Rendering a display in speedbar is completely flexible.  When your
button function is called, see @ref{Minor Display Modes}, and @ref{Major
Display Modes}, you have control to @code{insert} anything you want.

The conventions allow almost anything to be inserted, but several helper
functions are provided to make it easy to create the standardized
buttons.

To understand the built in functions, each `button' in speedbar consists
of four important pieces of data.  The text to be displayed, token
data to be associated with the text, a function to call, and some face to
display it in.

When a function is provided, then that text becomes mouse activated,
meaning the mouse will highlight the text.

Additionally, for data which can form deep trees, each line is given a
depth which indicates how far down the tree it is.  This information is
stored in invisible text at the beginning of each line, and is used by
the navigation commands.

@defun speedbar-insert-button text face mouse function &optional token prevline
This function inserts one button into the current location.
@var{text} is the text to insert.  @var{face} is the face in which it
will be displayed.   @var{mouse} is the face to display over the text
when the mouse passes over it.  @var{function} is called whenever the
user clicks on the text.

The optional argument @var{token} is extra data to associated with the
text.  Lastly @var{prevline} should be non-@code{nil} if you want this line to
appear directly after the last button which was created instead of on
the next line.
@end defun

@defun speedbar-make-tag-line exp-button-type exp-button-char exp-button-function exp-button-data tag-button tag-button-function tag-button-data tag-button-face depth

Create a tag line with @var{exp-button-type} for the small expansion
button.  This is the button that expands or contracts a node (if
applicable), and @var{exp-button-char} the character in it (@samp{+},
@samp{-}, @samp{?}, etc.).  @var{exp-button-function} is the function
to call if it's clicked on.  Button types are @code{bracket},
@code{angle}, @code{curly}, @code{expandtag}, @code{statictag}, and
@code{nil}.  @var{exp-button-data} is extra data attached to the text
forming the expansion button.

Next, @var{tag-button} is the text of the tag.
@var{tag-button-function} is the function to call if clicked on, and
@var{tag-button-data} is the data to attach to the text field (such a
tag positioning, etc.).  @var{tag-button-face} is a face used for this
type of tag.

Lastly, @var{depth} shows the depth of expansion.

This function assumes that the cursor is in the speedbar window at the
position to insert a new item, and that the new item will end with a CR.
@end defun

@defun speedbar-insert-generic-list level list expand-fun find-fun

At @var{level}, (the current indentation level desired) insert a generic
multi-level alist @var{list}.  Associations with lists get @samp{@{+@}}
tags (to expand into more nodes) and those with positions or other data
just get a @samp{>} as the indicator.  @samp{@{+@}} buttons will have the
function @var{expand-fun} and the token is the @code{cdr} list.  The
token name will have the function @var{find-fun} and not token.

Each element of the list can have one of these forms:

@table @code
@item (@var{name} . marker-or-number)
One tag at this level.
@item (@var{name} (@var{name} . marker-or-number) (@var{name} . marker-or-number) ... )
One group of tags.
@item (@var{name} marker-or-number (@var{name} . marker-or-number) ... )
One Group of tags where the group has a starting position.
@end table

When you use @code{speedbar-insert-generic-list}, there are some
variables you can set buffer-locally to change the behavior.  The most
obvious is @code{speedbar-tag-hierarchy-method}.
@xref{Tag Hierarchy Methods}.

@defvar speedbar-generic-list-group-expand-button-type
This is the button type used for groups of tags, whether expanded
or added in via a hierarchy method.  Two good values are
@code{curly} and @code{expandtag}.  Curly is the default button, and
@code{expandtag} is useful if the groups also has a position.
@end defvar

@defvar speedbar-generic-list-tag-button-type
This is the button type used for a single tag.
Two good values are @code{nil} and @code{statictag}.
@code{nil} is the default, and @code{statictag} has the same width as
@code{expandtag}.
@end defvar

@end defun

@node GNU Free Documentation License
@appendix GNU Free Documentation License
@include doclicense.texi


@node Index
@unnumbered Concept Index
@printindex cp

@bye
@c  LocalWords:  speedbar's xref slowbar kbd subsubsection
@c  LocalWords:  keybindings