#+title: Quick start: using xmobar

Xmobar can either be configured using the configuration language, or [[https://codeberg.org/xmobar/xmobar/src/branch/master/doc/using-haskell.org][used as a
Haskell library]] (similar to xmonad) and compiled with your specific
configuration. For an example of a configuration file using the plain
configuration language, see [[https://codeberg.org/xmobar/xmobar/src/branch/master/etc/xmobar.config][etc/xmobar.config]], and you can have a look at
[[https://codeberg.org/xmobar/xmobar/src/branch/master/etc/xmobar.hs][etc/xmobar.hs]] for an example of how to write your own xmobar using Haskell.

* Command line options

  xmobar can be either configured with a configuration file or with
  command line options. In the second case, the command line options will
  overwrite the corresponding options set in the configuration file.

  Example:

  #+begin_src shell
    xmobar -B white -a right -F blue -t '%LIPB%' -c '[Run Weather "LIPB" [] 36000]'
  #+end_src

  This is the list of command line options (the output of =xmobar --help=):

  #+begin_example
    Usage: xmobar [OPTION...] [FILE]
    Options:
    -h, -?        --help                 This help
    -v            --verbose              Emit verbose debugging messages
    -r            --recompile            Force recompilation
    -V            --version              Show version information
    -f font name  --font=font name       Font name
    -N font name  --add-font=font name   Add to the list of additional fonts
    -w class      --wmclass=class        X11 WM_CLASS property
    -n name       --wmname=name          X11 WM_NAME property
    -B bg color   --bgcolor=bg color     The background color. Default black
    -F fg color   --fgcolor=fg color     The foreground color. Default grey
    -i path       --iconroot=path        Root directory for icon pattern paths. Default '.'
    -A alpha      --alpha=alpha          Transparency: 0 is transparent, 255 is opaque. Default: 255
    -o            --top                  Place xmobar at the top of the screen
    -b            --bottom               Place xmobar at the bottom of the screen
    -d            --dock                 Don't override redirect from WM and function as a dock
    -a alignsep   --alignsep=alignsep    Separators for left, center and right text
                                         alignment. Default: '}{'
    -s char       --sepchar=char         Character used to separate commands in
                                         the output template. Default '%'
    -t template   --template=template    Output template
    -c commands   --commands=commands    List of commands to be executed
    -C command    --add-command=command  Add to the list of commands to be executed
    -x screen     --screen=screen        On which X screen number to start
    -p position   --position=position    Specify position of xmobar. Same syntax as in config file
    -T [format]   --text[=format]        Write output to stdout
    -D dpi        --dpi=dpi              The DPI scaling factor. Default 96.0

     Mail bug reports and suggestions to <mail@jao.io>
  #+end_example

* Configuration options
  :PROPERTIES:
  :CUSTOM_ID: configuration-options
  :END:
** Global options
   Here are all the global options that you can set within the =Config= block in
   your configuration and will define the overall behaviour and looks of your
   bar.

*** Fonts
   :PROPERTIES:
   :CUSTOM_ID: fonts
   :END:

   The following configuration options control the fonts used by xmobar:

    - =font= Name, as a string, of the default font to use.

    - =additionalFonts= Haskell-style list of fonts to us with the
      =fn=-template. See also =textOffsets= below. For example:

      #+begin_src haskell
        additionalFonts = [iconFont, altIconFont]
      #+end_src

    - =dpi= The DPI scaling factor, as a decimal, to use. If 0, negative, or not
      given, the default of 96 will be used, which corresponds to an average
      screen. A 10pt font will therefore scale to 10pt * (1/72 pt/inch) * (96
      pixel/inch) = 13.3 pixel. This is especially useful for HiDPI displays.

    The global font is used by default when none of the others is specified
    using the ~<fn=n>...</fn>~ markup, with ~n~ a 1-based index in the
    ~additionalFonts~ array.  So, for instance

    #+begin_src
      <fn=2>some text</fn>
    #+end_src

    will use, in the configuration above, ~altIconFont~ to display "some text".

    Font names use the [[https://docs.gtk.org/Pango/type_func.FontDescription.from_string.html][Pango format]].  Here are a few simple examples:

    #+begin_example
       DejaVu Sans Mono 10

       Iosevka Comfy Semi-Bold Italic 12

       Noto Color Emoji 10
    #+end_example

    We start with a family name (DejaVu Sans Mono, Iosevka Comfy, etc.),
    followed by optional, space-separated /style options/ (Semi-Bold Italic in
    the second example above), and ending with a size, in points.

    There are many possible style options (if your font supports them).  They
    can be

    - *Plain styles*: Normal, Roman, Oblique, Italic.
    - *Variants*: Small-Caps, All-Small-Caps, Petite-Caps, All-Petite-Caps,
      Unicase, Title-Caps.
    - *Weights*: Thin, Ultra-Light, Extra-Light, Light, Semi-Ligh, Demi-Light,
      Book, Regular, Medium, Semi-Bold, Demi-Bold, Bold, Ultra-Bold,
      Extra-Bold, Heavy, Black, Ultra-Black, Extra-Black.
    - *Strectch values:* Thin, Ultra-Light, Extra-Light, Light, Semi-Light,
      Demi-Light, Book, Regular, Medium, Semi-Bold, Demi-Bold, Bold,
      Ultra-Bold, Extra-Bold, Heavy, Black, Ultra-Black, Extra-Black.
    - *Gravity values*: Not-Rotated, South, Upside-Down, North, Rotated-Left,
      East, Rotated-Right, West.

   So you can add up to 5 style options per family:

   #+begin_example
     Monospace Italic All-Small-Caps Extra-Light Thin North 12
   #+end_example

   It's also possible to specify a list of fonts, separating them by commas,
   so that they act as fallbacks when the preceding one is not able to display
   a given glyph.  A bit confusingly, the styles and sizes come in reverse
   order after the families:

   #+begin_example
      Family 1, Family 2 Styles 2 Size 2, Styles 1 Size 1
   #+end_example

   For instance you could have:

   #+begin_example
      Souce Code Pro, Noto Color Emoji Regular 12, Semi-Bold 10
   #+end_example

   to use Source Code Pro Semi-Bold 10 when possible, and fall back to Noto
   Color Emoji Regular 12 for characters that the former cannot display.

**** X11 Bitmap fonts

     If you want to use traditional, non-aliased X11 fonts, you can do so via
     the [[https://www.cl.cam.ac.uk/~mgk25/ucs-fonts.html][Unicode fonts and tools for X11]] package, which provides bitmap
     versions of them, with a specification of the stytle ~"Fixed 8"~ for what
     in the old days would have been something like
     ~-Misc-Fixed-Medium-R-Normal--13-120-75-75-C-70-ISO10646-1~.  See also
     discussion in [[https://codeberg.org/xmobar/xmobar/issues/658][issue #658]].

*** Colors

    - =bgColor= Background color.

    - =fgColor= Default font color.

    - =alpha= The transparency. 0 is transparent, 255 is opaque.

*** Vertical offsets

    By default, all text and icons in the bar will be vertically centered
    according to the configured height of the bar.  You can override that
    behaviour with the following options:

    - =textOffset= The vertical offset, in pixels, for the text baseline. If
      negative or not given, xmobar will try to center text vertically.

    - =textOffsets= A list of vertical offsets, in pixels, for the text
      baseline, to be used with the each of the fonts in =additionalFonts=
      (if any). If negative or not given, xmobar will try to center text
      vertically for that font.

    - =iconOffset= The vertical offset, in pixels, for icons bottom line. If
      negative or not given, xmobar will try to center icons vertically.

*** Borders

    - =border= TopB, TopBM, BottomB, BottomBM, FullB, FullBM or NoBorder
      (default).

      TopB, BottomB, FullB take no arguments, and request drawing a border
      at the top, bottom or around xmobar's window, respectively.

      TopBM, BottomBM, FullBM take an integer argument, which is the margin,
      in pixels, between the border of the window and the drawn border.

    - =borderColor= Border color.

    - =borderWidth= Border width in pixels.

    - =iconRoot= Root folder where icons are stored. For =<icon=path/>= if
      path start with =/=, =./= or =../= it is interpreted as it is.
      Otherwise it will have

      #+begin_src haskell
        iconRoot ++ "/"
      #+end_src

      prepended to it. Default is =.=.

*** Bar position

    - =position= Top, TopH, TopHM, TopP, TopW, TopSize, Bottom, BottomH, BottomHM,
      BottomP, BottomW, BottomSize or Static (with x, y, width and height).

      TopP and BottomP take 2 arguments: left padding and right padding.

      TopW and BottomW take 2 arguments: an alignment parameter (L for left,
      C for centered, R for Right) and an integer for the percentage width
      xmobar window will have in respect to the screen width.

      TopSize and BottomSize take 3 arguments: an alignment parameter, an
      integer for the percentage width, and an integer for the minimum pixel
      height that the xmobar window will have.

      TopH and BottomH take one argument (Int) which adjusts the bar height.

      For example:

      #+begin_src haskell
        position = TopH 30
      #+end_src

      to make a 30 tall bar on the top, or

      #+begin_src haskell
        position = BottomH 30
      #+end_src

      to make a 30 tall bar on the bottom of the screen.  The corresponding
      variants ~TopHM~ and ~BottomHM~ allow you to specify, in addition to a
      height, margins (in pixels) with the borders of the screen (left, right
      top and bottom); so they take five integers as arguments.  For instance,
      if you one a margin of 2 pixels to the left of the top bar in the above
      example and 4 to its right and top, you could use:

      #+begin_src haskell
        position = TopHM 30 2 4 4 0
      #+end_src

      and similarly for ~BottomHM~.

      #+begin_src haskell
        position = BottomW C 75
      #+end_src

      to place xmobar at the bottom, centered with the 75% of the screen
      width. Or

      #+begin_src haskell
        position = BottomP 120 0
      #+end_src

      to place xmobar at the bottom, with 120 pixel indent of the left. Or

      #+begin_src haskell
        position = Static { xpos = 0 , ypos = 0, width = 1024, height = 15 }
      #+end_src

      or

      #+begin_src haskell
        position = Top
      #+end_src

    - =lowerOnStart= When True the window is sent the bottom of the window
      stack initially.

    - =hideOnStart= When set to True the window is initially not mapped,
      i.e. hidden. It then can be toggled manually (for example using the
      dbus interface) or automatically (by a plugin) to make it reappear.

    - =allDesktops= When set to True (the default), xmobar will tell the
      window manager explicitly to be shown in all desktops, by setting
      =_NET_WM_DESKTOP= to 0xffffffff.

    - =overrideRedirect= If you're running xmobar in a tiling window
      manager, you might need to set this option to =False= so that it
      behaves as a docked application. Defaults to =True=.

    - =pickBroadest= When multiple displays are available, xmobar will
      choose by default the first one to place itself. With this flag set to
      =True= (the default is =False=) it will choose the broadest one
      instead.

    - =persistent= When True the window status is fixed i.e. hiding or
      revealing is not possible. This option can be toggled at runtime.
      Defaults to False.

    - =wmClass= The value for the window's X11 ~WM_CLASS~ property. Defaults
      to "xmobar".

    - =wmName= The value for the window's X11 ~WM_NAME~ property. Defaults to
      "xmobar".

*** Text output

    - =textOutput= When True, instead of running as an X11 application,
      write output to stdout, with optional color escape sequences.  In
      this mode, icon and action specifications are ignored.  Default is
      False.

    - =textOutputFormat= Plain, Ansi or Pango, to emit, when in text
      mode, escape color sequences using ANSI controls (for terminals) or
      pango markup.  Default is Plain.

*** Commands and monitors

    - =commands= The list of monitors and plugins to run, together with their
      individual configurations. The [[https://codeberg.org/xmobar/xmobar/src/branch/master/doc/plugins.org][plugin documentation]] details all the
      available monitors, and you can also create new ones using Haskell.  See
      the [[#commands-list][commands list section]] below for more.

    - =sepChar= The character to be used for indicating commands in the
      output template (defaults to '%').

    - =alignSep= a 2-character string for aligning text in the output
      template. See [[#bar-sections][this section]] for details.

    - =template= The output template: a string telling xmobar how to display the
      outputs of all the =commands= above.  See [[#output-template][the next section]] for a full
      description.

** The =commands= list
   :PROPERTIES:
   :CUSTOM_ID: commands-list
   :END:

   The =commands= configuration option is a list of commands information
   and arguments to be used by xmobar when parsing the output template.
   Each member of the list consists in a command prefixed by the =Run=
   keyword. Each command has arguments to control the way xmobar is going
   to execute it.

   The options consist in a list of commands separated by a comma and enclosed
   by square parenthesis.

   Example:

   #+begin_src haskell
     [Run Memory ["-t","Mem: <usedratio>%"] 10, Run Swap [] 10]
   #+end_src

   to run the Memory monitor plugin with the specified template, and the
   swap monitor plugin, with default options, every second. And here's an
   example of a template for the commands above using an icon:

   #+begin_src haskell
     template = "<icon=/home/jao/.xmobar/mem.xbm/><memory> <swap>"
   #+end_src

   This example will run "xclock" command when date is clicked:

   #+begin_src haskell
     template = "<action=`xclock`>%date%</action>"
   #+end_src

   The only internal available command is =Com= (see below Executing
   External Commands). All other commands are provided by plugins. xmobar
   comes with some plugins, providing a set of system monitors, a standard
   input reader, an Unix named pipe reader, a configurable date plugin, and
   much more: we list all available plugins below.

   Other commands can be created as plugins with the Plugin infrastructure.
   See below.

** The output =template=
   :PROPERTIES:
   :CUSTOM_ID: output-template
   :END:

   The output template is how xmobar will end up printing all of your
   configured commands. It must contain at least one command. Xmobar
   will parse the template and search for the command to be executed
   in the =commands= configuration option. First an =alias= will be
   searched (some plugins, such as =Weather= or =Network=, have default
   aliases, see the [[https://codeberg.org/xmobar/xmobar/src/branch/master/doc/plugins.org][plugin documentation]]).  After that, the command
   name will be tried. If a command is found, the arguments specified
   in the =commands= list will be used.

   If no command is found in the =commands= list, xmobar will ask the
   operating system to execute a program with the name found in the
   template. If the execution is not successful an error will be
   reported.

*** Template syntax

    The syntax for the output template is as follows:

    - =%command%= will execute command and print the output. The output may
      contain markups to change the characters' color.

    - =<fc=#FF0000>string</fc>= will print =string= with =#FF0000= color
      (red). =<fc=#FF0000,#000000>string</fc>= will print =string= in red with a
      black background (=#000000=). Background absolute offsets can be specified
      for fonts. =<fc=#FF0000,#000000:0>string</fc>= will have a background
      matching the bar's height.  It is also possible to specify the colour's
      opacity, with two additional hex digits (e.g. #FF00000aa).

    - =<fn=1>string</fn>= will print =string= with the first font from
      =additionalFonts=. The index =0= corresponds to the standard font.  The
      standard font is also used if the index is out of bounds.

    - =<hspace=X/>= will insert a blank horizontal space of =X= pixels.
      For example, to add a blank horizontal space of 123 pixels,
      =<hspace=123/>= may be used.

      - =<box>string</box>= will print string surrounded by a box in the
        foreground color. The =box= tag accepts several optional arguments to
        tailor its looks: see next section.

    - =<icon=/path/to/icon.xbm/>= will insert the given bitmap. XPM image
      format is also supported when compiled with the =with_xpm= flag.

    - =<action=`command` button=12345>= will execute given command when
      clicked with specified buttons. If not specified, button is equal to 1
      (left mouse button). Using old syntax (without backticks surrounding
      =command=) will result in =button= attribute being ignored.

    - =<raw=len:str/>= allows the encapsulation of arbitrary text =str=
      (which must be =len= =Char=s long, where =len= is encoded as a decimal
      sequence). Careful use of this and =UnsafeStdinReader=, for example,
      permits window managers to feed xmobar strings with =<action>= tags
      mixed with un-trusted content (e.g. window titles). For example, if
      xmobar is invoked as

      #+begin_src shell
        xmobar -c "[Run UnsafeStdinReader]" -t "%UnsafeStdinReader%"
      #+end_src

      and receives on standard input the line

      #+begin_src shell
        <action=`echo test` button=1><raw=41:<action=`echo mooo` button=1>foo</action>/></action>`
      #+end_src

      then it will display the text
      =<action=`echo mooo` button=1>foo</action>=, which, when clicked, will
      cause =test= to be echoed.

      See the subsections below for more information on ~<box/>~,
      ~<icon/>~ and ~<action/>~.

    - The special characters =}= and ={= are used to delimit up to three sections
      in the bar that are drawn and aligned independently. See [[#bar-sections][this section]]
      for more.

*** Bar sections
    :PROPERTIES:
    :CUSTOM_ID: bar-sections
    :END:

     You can use the special characters =}= and ={= are used to delimit up to three
     sections in the bar, which are aligned and, if needed, overlapped
     according to these rules:

     - If the template has the form =L}M{R=, with L, R, M arbitrary specs, the
       monitors in =L= are drawn first, aligned to the left, then =R=, aligned to
       the right, and finally =M= is drawn centered in the bar. =R= is trimmed to
       the space left by =L=, and =M= is trimmed to the space left by =L= and =R=.  As
       a particular case, =}M{= will draw a single segment centered in the bar.

     - If the template has the form =L}{R=, =L= is drawn aligned to the left first
       and then =R=, aligned to the right and trimmed if needed to fit in the
       space left by =L=.

     - If the template has the form =}L{R=, =R= is drawn first, aligned to the
       right, and then =L=, aligned to the left and trimmed to the space left by
       =R=.

     When needed, sections are always trimmed on the right.  The section
     delimiters can be changed using the configuration option =alignSep,= a
     two-character string.

*** Boxes around text

    - =<box>string</box>= will print string surrounded by a box in the
      foreground color. The =box= tag accepts several optional arguments to
      tailor its looks:

      - =type=: =Top=, =Bottom=, =VBoth= (a single line above or below string, or
        both), =Left=, =Right=, =HBoth= (single vertical lines), =Full= (a rectangle,
        the default).
      - =color=: the color of the box lines.
      - =width=: the width of the box lines.
      - =offset=: an alignment char (L, C or R) followed by the amount of
        pixels to offset the box lines; the alignment denotes the position
        of the resulting line, with L/R meaning top/bottom for the vertical
        lines, and left/right for horizontal ones.
      - =mt=, =mb=, =ml=, =mr= specify margins to be added at the top,
        bottom, left and right lines.

      For example, a box underlining its text with a red line of width 2:

      #+begin_src shell
        <box type=Bottom width=2 color=red>string</box>
      #+end_src

      and if you wanted an underline and an overline with a margin of 2
      pixels either side:

      #+begin_src shell
        <box type=VBoth mt=2 mb=2>string</box>
      #+end_src

      When xmobar is run in text mode with output format swaybar, box
      types, colors and widths are valid too, but margins and offsets
      are ignored.

*** Bitmap icons

    It's possible to insert in the global templates icon directives of the
    form:

    prepended to it. Default is =.=.



    #+begin_src shell
      <icon=/path/to/bitmap.xbm/>
    #+end_src

    which will produce the expected result. Accepted image formats are XBM
    and XPM (when =with_xpm= flag is enabled). If path does not start with
    =/=, =./=, =../= it will have

    #+begin_src haskell
      iconRoot ++ "/"
    #+end_src

    prepended to it.

    Icons are ignored when xmobar is run in text output mode.

*** Mouse actions

    It's also possible to use action directives of the form:

    #+begin_src shell
      <action=`command` button=12345>
    #+end_src

    which will be executed when clicked on with specified mouse
    buttons.  This tag can be nested, allowing different commands to
    be run depending on button clicked.

    Actions work also when xmobar is run in text mode and used as
    the status command of swaybar.

* Runtime behaviour
** Running xmobar in text mode
   :PROPERTIES:
   :CUSTOM_ID: text-mode
   :END:

   By default, xmobar will run as an X11 application, in a docked window, but
   it is possible to redirect xmobar's output to the standard output,
   optionally with color escape sequences.  In this mode, xmobar can be run
   inside a terminal o console, or its output piped to other applications, and
   there is no need for an X11 display (so, for instance, you could pipe
   xmobar's output to a Wayland application, such as swaybar.)

   To run xmobar in text mode, either pass the =-T= flag to its
   invocation:

   #+begin_src shell
     xmobar -T /path/to/config &
   #+end_src

   or set the parameter =textOutput= to True in its configuration.  You
   can also specify the format of color escapes, for instance,
   omitting them altogether with ~Plain~:

   #+begin_src shell
     xmobar -TPlain /path/to/config &
   #+end_src

   Other options are ~Ansi~, ~Pango~, and ~Swaybar~.
** Showing xmobar output in Emacs tab or mode line
   Using xmobar's ANSI color text ouput, one can plug it inside Emacs, and
   display your monitors in the mode line or the tab bar.  The [[https://codeberg.org/xmobar/xmobar/src/branch/master/etc/xmobar.el][xmobar.el
   package]] provides a simple way of doing it.
** Using xmobar in wayland with swaybar or waybar
   :PROPERTIES:
   :CUSTOM_ID: wayland
   :END:

   In text mode, xmobar can be told to ouput its information using
   pango markup for colors and fonts, and it that way you can use it
   with swaybar or waybar, if you don't have actions or boxes in your
   template.  Here's a minimal ~bar~ configuration for sway's
   configuration file:

   #+begin_src conf
     bar {
     status_command xmobar -TPango
     pango_markup enabled
     }
   #+end_src

   In case you want to use boxes around text or click actions in your
   template, you can use instead the format ~Swaybar~, which supports
   both.  This output format follows the JSON /swaybar-protocol/
   defined by swaybar.  Configure it simply with:

   #+begin_src conf
     bar {
     status_command xmobar -TSwaybar
     }
   #+end_src

** Running xmobar with =i3status=

   xmobar can be used to display information generated by [[http://i3wm.org/i3status/][i3status]], a small
   program that gathers system information and outputs it in formats
   suitable for being displayed by the dzen2 status bar, wmii's status bar
   or xmobar's =StdinReader=. See [[http://i3wm.org/i3status/manpage.html#_using_i3status_with_xmobar][i3status manual]] for further details.

** Dynamically sizing xmobar

   See [[https://codeberg.org/xmobar/xmobar/issues/239#issuecomment-233206552][this idea]] by Jonas Camillus Jeppensen for a way of adapting
   dynamically xmobar's size and run it alongside a system tray widget such
   as trayer or stalonetray (although the idea is not limited to trays,
   really). For your convenience, there is a version of Jonas' script in
   [[https://codeberg.org/xmobar/xmobar/src/branch/master/etc/padding-icon.sh][etc/padding-icon.sh]].

** Signal handling

   xmobar reacts to ~SIGUSR1~ and ~SIGUSR2~:

   - After receiving ~SIGUSR1~ xmobar moves its position to the next screen.

   - After receiving ~SIGUSR2~ xmobar repositions itself on the current
     screen.
* The DBus interface

  When compiled with the optional =with_dbus= flag, xmobar can be controlled
  over dbus. All signals defined in [[https://codeberg.org/xmobar/xmobar/src/branch/master/src/Xmobar/System/Signal.hs][src/Signal.hs]] as =data SignalType= can now
  be sent over dbus to xmobar.

  Due to current limitations of the implementation only one process of xmobar
  can acquire the dbus. This is handled on a first-come-first-served basis,
  meaning that the first process will get the dbus interface. Other processes
  will run without further problems, yet have no dbus interface.

  - Bus Name: =org.Xmobar.Control=
  - Object Path: =/org/Xmobar/Control=
  - Member Name: Any of SignalType, e.g. =string:Reveal=
  - Interface Name: =org.Xmobar.Control=

  An example using the =dbus-send= command line utility:

  #+begin_src shell
    dbus-send \
      --session \
      --dest=org.Xmobar.Control \
      --type=method_call \
      --print-reply \
      '/org/Xmobar/Control' \
      org.Xmobar.Control.SendSignal \
      "string:SetAlpha 192"
  #+end_src

  It is also possible to send multiple signals at once:

  #+begin_src shell
    # send to another screen, reveal and toggle the persistent flag
    dbus-send [..] \
              "string:ChangeScreen 0" "string:Reveal 0" "string:TogglePersistent"
  #+end_src

  The =Toggle=, =Reveal=, and =Hide= signals take an additional integer
  argument that denotes an initial delay, in tenths of a second,
  before the command takes effect, while =SetAlpha= takes a new alpha
  value (also an integer, between 0 and 255) as argument.

** Example: using the DBus IPC interface with XMonad

   Bind the key which should {,un}map xmobar to a dummy value. This is
   necessary for {,un}grabKey in xmonad.

   #+begin_src haskell
     ((0, xK_Alt_L), pure ())
   #+end_src

   Also, install =avoidStruts= layout modifier from =XMonad.Hooks.ManageDocks=

   Finally, install these two event hooks (=handleEventHook= in =XConfig=)
   =myDocksEventHook= is a replacement for =docksEventHook= which reacts on unmap
   events as well (which =docksEventHook= doesn't).

   #+begin_src haskell
     import qualified XMonad.Util.ExtensibleState as XS

     data DockToggleTime = DTT { lastTime :: Time } deriving (Eq, Show, Typeable)

     instance ExtensionClass DockToggleTime where
         initialValue = DTT 0

     toggleDocksHook :: Int -> KeySym -> Event -> X All
     toggleDocksHook to ks ( KeyEvent { ev_event_display = d
                                      , ev_event_type    = et
                                      , ev_keycode       = ekc
                                      , ev_time          = etime
                                      } ) =
             io (keysymToKeycode d ks) >>= toggleDocks >> return (All True)
         where
         toggleDocks kc
             | ekc == kc && et == keyPress = do
                 safeSendSignal ["Reveal 0", "TogglePersistent"]
                 XS.put ( DTT etime )
             | ekc == kc && et == keyRelease = do
                 gap <- XS.gets ( (-) etime . lastTime )
                 safeSendSignal [ "TogglePersistent"
                             , "Hide " ++ show (if gap < 400 then to else 0)
                             ]
             | otherwise = return ()

         safeSendSignal s = catchX (io $ sendSignal s) (return ())
         sendSignal    = withSession . callSignal
         withSession mc = connectSession >>= \c -> callNoReply c mc >> disconnect c
         callSignal :: [String] -> MethodCall
         callSignal s = ( methodCall
                         ( objectPath_    "/org/Xmobar/Control" )
                         ( interfaceName_ "org.Xmobar.Control"  )
                         ( memberName_    "SendSignal"          )
                     ) { methodCallDestination = Just $ busName_ "org.Xmobar.Control"
                         , methodCallBody        = map toVariant s
                         }

     toggleDocksHook _ _ _ = return (All True)

     myDocksEventHook :: Event -> X All
     myDocksEventHook e = do
         when (et == mapNotify || et == unmapNotify) $
             whenX ((not `fmap` (isClient w)) <&&> runQuery checkDock w) refresh
         return (All True)
         where w  = ev_window e
             et = ev_event_type e
   #+end_src