InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/X/epoch/Epoch.FAQ

Text File | 1992-07-01 | 51.4 KB | 1,350 lines

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*               Epoch FAQ (Frequently Asked Questions)
*        (or at least Occasionally Wondered-About Questions)

*        Maintained by Marc Andreessen ([e-mail])
*     Last Modified Mon May 18 22:17:07 1992 -- Marc Andreessen

If you are viewing this text in a GNU Emacs buffer, you can type
"M-2 C-x $" to get an overview of just the questions.  Then, when
you want to look at the text of the answers, just type "C-x $".

To search for a question numbered XXX, type "M-C-s ^XXX:", followed by
a C-r if that doesn't work; type ESC to end the search.

The latest version of this file will be always available via anonymous
FTP to ftp.ncsa.uiuc.edu (141.142.20.50) in /outgoing/marca/epoch.

Please feel free to send comments, suggestions, additions, and
corrections to [e-mail].

*                   === REALLY IMPORTANT NOTE ===

Unless otherwise attributed, information below is based only on Yours
Truly's use and experience with Epoch and is BY NO MEANS GUARANTEED to
be correct, complete, or even coherent.  If it works for you, great;
if it doesn't, let me know, but there are no guarantees.

*             === CHANGES IN THIS VERSION OF THE FAQ ===

  Here is a list of changes made since the FAQ's last monthly
  posting to gnu.epoch.misc and news.answers:

  a) Addition of this section of the FAQ.
  b) F-1: Two more ways to fix the backspace key.
  c) G-2: Patch to make drag style always display.
  d) Z-3: Only applies to X11R5 multiscreen servers, plus workaround.

*                       === PREREQUISITES ===

  In the answers that follow, I assume at least a little familiarity
  with GNU Emacs Lisp (elisp).  Suggested resources that could be
  considered necessary references for material in this FAQ are:

--> The GNU Emacs and Epoch manuals (available online via C-h i).

--> The GNU Elisp manual (available via anonymous FTP from
    prep.ai.mit.edu (18.71.0.38) as /pub/gnu/elisp-manual-1.03.tar.Z).

--> The gnu.emacs.help FAQ in the file etc/FAQ (the latest version
    is available in the gnu.emacs.help Usenet newsgroup or via FTP from
    pit-manager.mit.edu (18.172.1.27) in /pub/usenet/gnu.emacs.help).

*                          === CAVEATS ===

  Many of the answers given herein APPLY ONLY to Epoch 4.0 (and also may
  only apply to 4.0 beta level 0 or later).  When I know about them,
  3.2'isms and 4.0-alpha'isms are mentioned also.  Also, my Epoch
  platform is an SGI IRIS Indigo XS running IRIX 4.0.2; other
  configurations may behave differently.  Please let me know of any such
  differences.  (Now that an official release of 4.0 has been made,
  details about previous versions will be removed at some point in the
  future.)

*                    === EPOCH AND GNU EMACS ===

A-1: What is Epoch?

  Epoch is GNU Emacs on steroids: an adaptation of GNU Emacs with lots
  of additional support for features made possible by the X11 windowing
  system.  These features include multiple editing windows, arbitrary
  colors and fonts (fixed-width and proportional), selectable zones per
  buffer with arbitrary display styles (font, color, underline, stipple,
  pixmap), an optional separate minibuffer window, improved keyboard and
  mouse handling, full 8-bit character set support, and more.

  Epoch, like GNU Emacs, is very customizable; much of this FAQ
  describes ways to customize Epoch for specific purposes.

A-2: How can I get Epoch?

  Epoch is available via anonymous FTP to cs.uiuc.edu (128.174.252.1)
  in pub/epoch-files/epoch.  The main file of interest is currently
  epoch-4.0p1.tar.Z.

  According to Simon Marshall ([e-mail]):

  Like GNU & X11 stuff, epoch is available in the UK from
  uk.ac.ic.doc.src (00000510200001).  You can log on; there's help to
  tell you the different ways of getting source.  Epoch is in
  /gnu/epoch.

  Epoch is also available from aix370.rrz.uni-koeln.de (134.95.132.2)
  in /gnu/emacs/epoch.

  Volunteers for other FTP sites outside the United States, or for
  mail access to Epoch source, please step forward.

A-3: What is the latest version of Epoch?

  The latest version is 4.0 patchlevel 1.  Previous versions still in
  use by some people include 4.0 patchlevel 0, the 4.0 alpha and beta
  levels, and version 3.2.

  Epoch 4.0p1 (a.k.a. 4.0 patchlevel 1) is based on GNU Emacs 18.58,
  which is the most recent version of GNU Emacs.

A-4: What are the differences between the various versions of Epoch?

  NOTE: Many bugs were also fixed from version to version; for the
  most part, those fixes aren't mentioned here.)

  Important differences between 3.2 and 4.0-alpha include:
     [From initial announcement of Epoch 4.0a0.]

  a)  Based on 18.57 GNU Emacs.  [3.2 was based on 18.55.]
  b)  Completely rebuilt display code: now supports proper proportional
      fonts.
  c)  Changes from attributes to styles.
  d)  Minibuffer can now be in its own window (traditional Epoch) or in the
      same window as the epoch screens (traditional GNU Emacs).
  e)  Mouse maps now based on Ken Laprade's mouse package.
  f)  Selections rather than cut-buffers (but cut-buffers still work).
  g)  Runs on more platforms.

  Important differences between 4.0-alpha and 4.0-beta include:
     [From 4.0-beta README.]

  h)  Includes code to build ASCII version of GNU Emacs 18.57.
  i)  Support for sharing lisp directory between Epoch and GNU Emacs
      18.57 installed elsewhere.
  j)  "Buttons" became "zones".  (See question A-5 below.)
  k)  Performance enhancements.

  Important differences between 4.0b0 and 4.0b1 include:
     [From 4.0b1 README.]

  l)  Based on 18.58 GNU Emacs.
  m)  Bug-fixes for graphical zone support.
  n)  Epoch no longer reads $HOME/.Xdefaults on its own; it assumes
      that Epoch resources are available in the X server's resource
      database.  (This is ICCCM-compliant behavior, which makes Epoch
      more like other X applications).

  Important differences between 4.0b1 and 4.0p0 include:
     [From preliminary announcement of 4.0p0.]

  o)  Epoch will read $HOME/.Xdefaults on its own if the '-ud' command
      line option is used; otherwise, it uses the X resource database
      only.
  p)  Additional support for 8-bit fonts and hypertext info in the
      contrib directory.

  Important differences between 4.0p0 and 4.0p1 include:
     [From announcement of 4.0p1.]

  q)  Added support for pasting from Epoch to Open Windows clients.
  r)  Ability to set cursor foreground/background.
  s)  Ability to load standard X bitmap files as well as XPM pixmap
      files.
  t)  Replacement contrib/hyper/info.el for broken 4.0p0 version.

A-5: I recently moved to Epoch 4.0b0 (or later), and elisp code that
 worked before has stopped working.  Why?

  Change c) for Epoch 4.0b0 is probably the culprit; the term "zone" was
  chosen to replace the term "button", changing the names of all the
  button-related function names and variables.  There are two ways to
  deal with this change:

  METHOD #1:

    Put the following command at the head of each file of elisp code
    that uses buttons:

    (require 'button)

    (This simply does a series of fset's to replace the "button" names
    with the new "zone" names.)

  METHOD #2:

    Convert all references of "button" to "zone".  You can use the
    function convert-current-buffer in epoch-lisp/convert-buttons.el
    (in the Epoch distribution) to do this automatically.

    NOTE: There may be additional problems; in particular, since
    attributes were eliminated in Epoch 4.0a0, any use of them will
    have to be eliminated also.  This is less simple than switching
    from buttons to zones.  Fortunately, most Epoch packages on the
    net now support 4.0.  Therefore, I won't bother to come up with an
    answer for this one (unless someone actually needs to know).

A-6: I recently moved to Epoch 4.0b1 (or later), and my X resources are
 suddenly being ignored.  Why?

  Change n) for Epoch 4.0b1 above has caused some trouble for people
  moving to 4.0b1 (or later).  Previous to 4.0b1, Epoch would always
  extract its X default resources from the user's .Xdefaults file by
  hand; this is no longer the case.  If Epoch 4.0b1 (or later) isn't
  picking up resources like previous versions did on your system, prior
  to starting Epoch do this:

    xrdb -merge $HOME/.Xdefaults

  This makes the X server's database pick up and maintain all of the
  resource definitions found in $HOME/.Xdefaults.

  If you are running Epoch 4.0p0 or later you can use the '-ud'
  command line flag to force Epoch to manually scan $HOME/.Xdefaults.

  A second problem is that Epoch 4.0b1 (or later) uses the first word
  in the command that executed Epoch (argument 0) to search the X
  resource database for Epoch resources.  Thus, if you invoke Epoch
  with the name:

    epoch-4.0.1

  ...Epoch will use the string 'epoch-4.0.1' to search the resource
  database, thereby missing the resources specified by the name
  'epoch'.  The workaround is to use the '-rn' command-line option
  like so:

    epoch-4.0.1 -rn epoch

  If you are running Epoch 4.0p1 or later you can use the '-name' flag
  (which is standard for X applications) in place of '-rn', like so:

    epoch-4.0.1 -name epoch

  [From Martin Boyer ([e-mail]).]

A-7: What's the difference between Epoch and GNU Emacs version 19?

  To quote directly from the GNU 'status' file (obtained via anonymous
  FTP to prep.ai.mit.edu (18.71.0.38) as /pub/gnu/status):

  -- BEGIN QUOTE -----------------------------------------------------
  Emacs 18 maintenance continues for simple bug fixes.  Version 19
  approaches release, counting among its new features before and after
  change hooks, source-level debugging of Emacs Lisp programs, X
  selection processing, including CLIPBOARD selections, scrollbars,
  support for European character sets, floating point numbers,
  per-buffer mouse commands, interfacing with the X resource manager,
  mouse-tracking, lisp-level binding of function keys, and multiple X
  windows (`screens' to emacs).

  Thanks go to Alan Carroll and the people who worked on Epoch for
  generating initial feedback to a multi-windowed emacs.  Emacs 19
  supports two styles of multiple windows, one with a separate screen
  for the minibuffer, and another with a minibuffer attached to each
  screen.

  A couple of other features of Version 19 are buffer allocation, which
  uses a new mechanism capable of returning storage to the system when a
  buffer is killed, and a new input system--all input now arrives in the
  form of Lisp objects.

  Other features under consideration for later releases of Version 19
  include:

  ** Associating property lists with regions of text in a buffer.
  ** Multiple font, color, and pixmaps defined by those properties.
  ** Different visibility conditions for the regions, and for various
     windows showing one buffer.
  ** Hooks to be run if point or mouse moves outside a certain range.
  ** Incrementally saving undo history in a file, so that recover-file
     also reinstalls buffer's undo history.
  ** Static menu bars, and better pop-up menus.
  -- END QUOTE -------------------------------------------------------

  Epoch currently supports much of the new functionality of GNU Emacs
  v19, including some features that apparently won't be immediately
  available in GNU Emacs v19 (notably, associating property lists with
  regions of text, and multiple fonts/colors/pixmaps defined by those
  properties).

  A postscript to this answer is a message that Richard Stallman
  (Mr. Gnu himself) posted to gnu.emacs.help in Apr 1992:

  -- BEGIN QUOTE -----------------------------------------------------
  Emacs 19 won't support text highlighting, but a later version will.

  We have code basically working for attaching arbitrary properties to
  parts of the text, including choice of font and color.

  This feature is designed for attributes which are considered part of
  the text itself.  What Epoch provides is highlighting that is part
  of the presentation of the text, not logically part of the text itself.
  That is useful also; I hope we will find the wherewithal to implement
  that along with the other highlighting features.
  -- END QUOTE -------------------------------------------------------

*                     === CONFIGURING EPOCH ===

B-1: How can my .emacs file deal with both GNU Emacs and Epoch?

  An easy way to handle both GNU Emacs and Epoch within the same .emacs
  file is to define a variable 'running-epoch' as follows:

  (defvar running-epoch (boundp 'epoch::version))

  Then, the rest of your .emacs file can look like this:

    (if running-epoch
      (progn
        ... [Epoch-specific code here] ...
    ))

  ... [Emacs code here] ...

  (After this, when I refer to 'your .emacs file', read that as 'the
  Epoch-specific portion of your .emacs file', under the assumption that
  you have both general and Epoch-specific parts as detailed above.)

  If you have a large amount of Epoch-specific code it may be better to
  put it in a separate file (e.g., "epoch-specific.el"), possibly
  byte-compile it, then load it from your .emacs file like so:

    (if (boundp 'epoch::version) (load "epoch-specific"))

B-2: What if I want to have separate sections for Epoch 3.2 and 4.0 in
 my .emacs file?

  The variable 'epoch::version' is a string that contains the current
  Epoch version ID.  For instance, evaluating epoch::version under
  Emacs4.0b0 (the first beta level) gives:

  "Epoch 4.0 Beta Patchlevel 0"

  A simple way to determine if version 4.x is running is to do something
  like this:

    (string-match " 4" epoch::version)

  This will result in 't' if the string " 4" is a substring of
  epoch::version (as would be the case when epoch::version is
  "Epoch 4.0 ..."), and 'nil' otherwise.

B-3: How can I configure Epoch to support full 8-bit character sets?

  The variable 'ctl-arrow', which is a buffer-local variable, controls
  how control characters are displayed.  By setting this variable to
  something non-nil and non-t, you get full 8-bit characters.  To get
  8-bit characters in all buffers, put this in your .emacs file:

    (setq-default ctl-arrow 'foo)

  [Thanks to Pierre Bondono ([e-mail]) and Tor Lillqvist
   ([e-mail]) for the following:]

  There is also a package in the Epoch contrib directory that deals
  with 8-bit characters better than the above technique.  See the
  directory contrib/keriven in the Epoch distribution.

*                          === WINDOWS ===

C-1: How do I get the minibuffer back at the bottom of my edit window?

  Start Epoch with the command-line option '-nm'.  Alternately, in your
  general .Xdefaults file, specify:

    epoch.nonlocal.minibuf: False

  (These techniques only work in Epoch 4.0.)

C-2: How do I prevent the initial edit window from appearing?  (In
 other words, how do I get only the minibuffer upon startup?)

  There is an undocumented variable that controls whether or not an
  initial edit window will be provided.  (This variable is documented as
  of 4.0p0.)  By default, of course, one is; to stop this from
  happening, put the following in your .emacs:

    (setq inhibit-initial-screen-mapping t)

  This will have no effect if you're using local minibuffers (i.e. when
  the minibuffer is a part of each edit window), as described above.

  [Thanks to Chris Love ([e-mail]).]

C-3: How do I stop the windows from automatically raising upon entry?

  The easiest way to do this, if you're running Epoch 4.0b0 or later, is
  to specify the following in your .emacs file:

    (setq auto-raise-screen 'minibuf)

  If you're running a version of Epoch prior to Epoch 4.0b0, the
  following code also works:

    (setq auto-raise-screen nil)
    (push (function (lambda () (raise-screen (minibuf-screen))))
      *select-screen-hook*)

  Both of the above solutions still make the minibuffer raise when an
  Epoch edit window is entered; if you don't want the minibuffer to
  raise itself either, just do the following instead:

    (setq auto-raise-screen nil)

C-4: How do I change the cursor?

  Another noticeable change from GNU Emacs is the cursor glyph (which is
  a pencil shape).  To change this to a more normal-appearing arrow
  shape, put this in your .emacs file:

    (cursor-glyph 68)
    (cursor-glyph 68 (epoch::minibuf-screen))
    (push '(cursor-glyph . 68) epoch::screen-properties)

  NOTE: You can specify a different cursor glyph for the minibuffer,
  if you like.

  There are also X resources for the screen and minibuffer cursor
  glyphs; equivalent to the above elisp code would be the following (in
  your .Xdefaults file):

    epoch.screen.cursor.glyph: 68
    epoch.minibuf.cursor.glyph: 68

  For either of these approaches, any valid cursor ID number will do; to
  see the available cursors and their ID numbers, take a look at the
  file /usr/include/X11/cursorfont.h.

  (See below for details on how to customize the cursor glyph based on
  the mode of a screen's initial buffer.)

C-5: How do I define edit screen attributes on a per-mode basis?  Or,
 how do I make my C++ edit windows come up with 48 lines and a big
 round dot for a cursor?

  You can define styles for new edit screens created with
  find-file-other-screen (which is, by default, bound to 'C-z 4 C-f' and
  'C-z 4 f') based on the initial buffer's mode like so:

    (setq epoch-mode-alist
      (append (list
          (cons 'c-mode
            (list
              (cons 'geometry "80x52")
              (cons 'cursor-glyph 94)))
          (cons 'LaTeX-mode
            (list
              (cons 'geometry "90x48")
              (cons 'cursor-glyph 58)))
          (cons 'c++-mode
            (list
              (cons 'geometry "80x48")
              (cons 'cursor-glyph 38))))
        epoch-mode-alist))

C-6: How do I make Epoch manage edit window and icon names based on the
 name of the current buffer(s)?

  The base Epoch distribution doesn't support this, but there have been
  a number of small packages written that accomplish this.  The one
  Yours Truly uses was written by Derek Ney ([e-mail])
  and is up for anonymous FTP at ftp.ncsa.uiuc.edu (141.142.20.50) as
  /outgoing/marca/epoch/derek-title.el.Z.

C-7: How do I iconify my entire Epoch session at once?

  By default, 'C-z i' is bound to iconify-screen, which only iconifies
  the current edit window.  To iconify everything, define a small
  function iconify-everything in your .emacs file like so:

    (defun iconify-everything ()
      "Iconify entire Epoch session at once."
      (interactive)
      (dolist (s (screen-list))
        (iconify-screen s))
      (iconify-screen 0)
    )

  Then bind it to a key sequence (e.g. 'C-z C-i') like so:

    (global-set-key "\C-z\C-i" 'iconify-everything)

C-8: Does Epoch support scrollbars?

  No; native support for scrollbars is a technical challenge that so far
  no one has taken up for either GNU Emacs or Epoch.

  [Thanks to Pierre Bondono ([e-mail]) for the following:]

  Related to this, there is a ``scrolling concept'' inside the IMOUSE
  packages that may be of interest.  IMOUSE can be found in
  contrib/boyer in the Epoch distribution or via anonymous FTP from
  ireq-robot.hydro.qc.ca (131.195.2.130); see question H-1 below.

C-9: My workstation's screen area is overwhelmed by all the windows I
 create in my Epoch editing sessions.  How can I squeeze more windows
 into my working environment?

  This is only a half-facetious question; there's only room on most
  workstation screens (usually 1024x768 or 1280x1024 pixels in area) for
  a couple of windows with decent-sized fonts.  To help alleviate the
  discomfort of cramped space, try the 'tvtwm' window manager.  (I sound
  like a cough-drop commercial.)

  Tvtwm, a superset of the twm window manager, allows windows to be
  placed on a virtual root window that can be of any size (for example,
  3000 by 3000 pixels).  This virtual root can be navigated via tvtwm's
  'panner', a reduced-size overview of your entire environment.

  Tvtwm can be found on your local comp.sources.x archive or in the
  X11R4 and X11R5 distributions.  Try anonymous FTP to ftp.uu.net
  (137.39.1.9) in /usenet/comp.sources.x.

*                      === COLORS AND FONTS ===

D-1: How do I interactively select my foreground color.

  First, define a style for each of your desired foreground colors in
  your .emacs file, like so:

    (setq red-style (make-style))
    (set-style-foreground red-style "red")

  Then, define a short command 'goto-style' like so:

    (defun goto-style (newstyle)
      "Set current buffer to a given font NEWSTYLE."
      (setq buffer-style newstyle)
      (redraw-display))

  Next, bind commands to keys like so:

    (global-set-key "\C-c1" (definteractive (goto-style red-style)))

  This binds a command that changes the current foreground color to red
  to the key sequence C-c 1.

  The following function allows you to interactive specify a new color
  for the current buffer's foreground:

    (defun set-foreground (newfg)
      "Set current foreground color to NEWFG."
      (interactive "sForeground color: ")
      (set-style-foreground buffer-style newfg)
      (redraw-display))

  This function is activated by typing:

    M-x set-foreground

  Or, it can be bound to a key like so:

    (global-set-key "\C-z\C-s" 'set-foreground)

D-2: How do I switch fonts interactively?

  To change fonts, you don't have to define new styles.  Just define a
  short command 'goto-font', like so:

    (defun goto-font (newfont)
      "Set current buffer to a given font NEWFONT."
      (font newfont)
      (redraw-display))

  Then, bind commands to keys like so:

    (global-set-key "\C-c1" (definteractive (goto-font "8x13")))

  This changes the current edit window's font to "8x13" when the key
  sequence 'C-c 1' is entered.

  The following function allows you to interactively input a font name:

    (defun set-font (newfont)
      "Set current font to NEWFONT."
      (interactive "sFont name: ")
      (font newfont)
      (redraw-display))

  This function is activated by typing:

    M-x set-font

  Or, it can be bound to a key like so:

    (global-set-key "\C-z\C-s" 'set-font)

  If the font you specify with either of these methods isn't valid for
  your X server (i.e. if the font doesn't exist in a directory listed in
  your X server's font path and in that directory's fonts.dir file, or
  isn't available from the font server if you're running X11R5), you
  will get this message in your minibuffer:

  Bad font name

  Font names are ordinary X font names; for example, a 14-point non-bold
  non-italic Helvetica font can be referred to as:

  "*helvetica-medium-r-normal--14*"

  The standard X client 'xlsfonts' will give you a list of the fonts
  registered with your X server.  The standard X client 'xfontsel' lets
  you interactively put together an X font specification string based on
  individual attributes (e.g., family, size).

D-3: How can I associate a certain foreground color with a file
 so that every time I load that file my foreground color is
 automatically set?

  You can easily do this by using GNU Emacs' ability to handle file
  variables.  For example, if you have defined style 'red-style' to
  specify a red foreground color, and want file 'foobar.c' to always
  have the foreground color red, add this to the bottom of 'foobar.c':

    ^L
    /*
    Local Variables:
    buffer-style: red-style
    End:
    */

  NOTE: '^L' is a newline character; you can enter one in an edit
  buffer by typing 'C-q C-l'.

  Then, whenever 'foobar.c' is loaded, the variable 'buffer-style' will
  be set to 'red-style', and as a result the foreground color for that
  buffer will be red.

D-4: How do I design my own really funky technicolor modeline?

  Using the tried-and-true Learning By Example(tm) educational method,
  I'll just give the (heavily commented) elisp code I use to define my
  own customized modeline:

  ;; Define styles for the modeline.
  (setq cyan-style (make-style))
  (set-style-foreground cyan-style "#6fcfef")
  (setq red-style (make-style))
  (set-style-foreground red-style "red")
  (setq yellow-style (make-style))
  (set-style-foreground yellow-style "yellow")

  ;; Make display-time display day and date also.
  (setq display-time-day-and-date t)

  ;; Display time, day, and date in modeline.
  (display-time)

  ;; List full filename, with path.
  (set-default 'mode-line-buffer-identification
             '(buffer-file-name ("%f") ("%b")))

  ;; This actually turns inverse-video _off_ for the modeline.
  (setq mode-line-inverse-video t)

  ;; Set the modeline itself.
  (setq default-mode-line-format
    (list red-style "--"
          ;; Buffer name.
          yellow-style 'mode-line-buffer-identification
          red-style "-"
          ;; Buffer status (read-only, unchanged, changed).
          cyan-style "%*%*"
          red-style "-"
          ;; Position in buffer.
          cyan-style "%[%3p%]"
          red-style "--"
          ;; Current time.
          yellow-style "%M"
          red-style "--("
          ;; Mode name.
          cyan-style 'mode-name 'minor-mode-alist "%n"
            'mode-line-process
          red-style ")-%-"))

D-5: How do I replace the mouse region selection underlining with a
 different style?

  You can override the variable 'motion::style' with your own style,
  like so:

    (setq motion::style (make-style))

  Now, you can set the various elements of this style as you please.
  Several examples follow.

  To have just the text foreground color change on mouse selection, do:

    (set-style-foreground motion::style "yellow")
    (set-style-background motion::style (background))

  NOTE: Replace "yellow" with any desired X color name.

  To have the selected region appear as reverse video, try:

    (set-style-foreground motion::style (background))
    (set-style-background motion::style (foreground))

  To have the selected region appear with an overlayed diagonal stipple
  pattern, try:

    (set-style-background motion::style "red")
    (set-style-background-stipple motion::style
      (make-bitmap 4 4 "\167\273\335\356"))

  Also note that, if you like, you can just modify the style bound by
  default to motion::style instead of actually creating a new style.
  The style bound to motion::style has default settings as follows:

    (set-style-foreground motion::style (foreground))
    (set-style-background motion::style (background))
    (set-style-underline motion::style (foreground))

  So, for instance, to get yellow underlining, you could just do:

    (set-style-underline motion::style "yellow")

*                           === MENUS ===

E-1: Does Epoch support popup menus or menubars?

  The base Epoch distribution does not have native support for popup
  menus or menubars.  However, there are other ways to use menus with
  Epoch.

  METHOD #1:

  If you're running the window manager GWM (available via anonymous FTP
  to export.lcs.mit.edu (18.24.0.12) in /contrib/gwm), you can use the
  Epoch contrib 'wm-menu' package (found in the contrib directory in the
  Epoch distribution) to have GWM provide menus that pass messages to
  Epoch.

  METHOD #2:

  If you're running a window manager that has user-specifiable menus (as
  all of the common window managers do), you can use the xsendevent to
  send events (e.g. keystrokes) to Epoch by activating window
  manager-produced menu entries.

  An example menu (in twm format) is as follows:

  menu "epoch"
  {
    "Epoch Menu"   f.title
    "Undo"         ! "xse -window ClickWindow 'Ctrl<Key>x' '<Key>u'"
    "Quit"         ! "xse -window ClickWindow 'Ctrl<Key>x' 'Ctrl<Key>c'"
  }

  Button3 = c : root : f.menu "epoch"

  The epoch menu is activated when Ctrl-Btn3 is pressed on the root
  window.  You theoretically will have to point at an Epoch window and
  click with the left mouse button (after activating a menu entry) for a
  command to take effect.  However, I [Marc] haven't been able to
  actually get the ClickWindow option to work; xsendevent (version 2.0)
  always wants to send the event to the window that contains the
  pointer.  So what I do instead is define a twm titlebutton for the
  epoch menu like so:

  menu "epoch"
  {
    "Epoch Menu"   f.title
    "Undo"         ! "xse 'Ctrl<Key>x' '<Key>u'"
    "Quit"         ! "xse 'Ctrl<Key>x' 'Ctrl<Key>c'"
  }

  LeftTitleButton "~/epochbitmap.bm" = f.menu "epoch"

  ("~/epochbitmap.bm" is a little X bitmap that displays as the button's
  label.)  Now pulling down the menu and activating an entry will send
  the keystrokes to the current window.  This is not an ideal solution,
  since all windows (Epoch or not) in the session will have the menu
  attached to them, but it does work and is quite convenient for use
  with Epoch.

  To bind arbitrary commands to menu entries in this manner, you need to
  define a unique keystroke pattern (with global-set-key) for each
  command and then send that keystroke pattern with xsendevent via the
  menu.  See the section on rebind-key (below) for more information on
  this technique.  (Of course, you are also free to have xsendevent send
  a key sequence like 'ESC x u n d o RET' directly to Epoch.)

  You can get xsendevent at export.lcs.mit.edu (18.24.0.12) in /contrib
  or at ftp.uu.net (137.39.1.9) in /packages/X/contrib.

  [From Philippe Bondono ([e-mail]).]

  METHOD #3:

  A completely different technique involves using a separate X client
  that posts a menu and has Epoch (or for that matter, GNU Emacs)
  receive commands from it.  One example of this technique is
  /gnu/emacs/buttons.tar.Z from anonymous FTP to aix370.rrz.uni-koeln.de
  (134.95.132.2).

  METHOD #4:

  Another method uses xmenu or xmenu2, which are available at any
  comp.sources.x archive.  (If you don't know of such an archive, try
  anonymous FTP to ftp.uu.net (137.39.1.9) in /usenet/comp.sources.x.)
  After you have compiled xmenu or xmenu2, define the following function
  in your .emacs file:

  (defun interpret-output (process output)
    (command-execute (car (read-from-string output))))

  Then you can define other functions that make specific menus, with
  menu entries bound to commands, like the following example shows:

  (defun make-menu ()
    (interactive)
    (set-process-filter (start-process "xmenu" nil
        "/usr/local/bin/xmenu" "-heading" "Epoch Menu"
        "Undo=undo")
      'interpret-output))

  This example uses /usr/local/bin/xmenu to post a one-entry menu to the
  screen; the menu entry's label is "Undo" and the action it triggers in
  Epoch is 'undo'.  Specify as many "Label=action" pairs as you like as
  part of the start-process command.

  [From Philippe Bondono ([e-mail]).]

  If you use XView/Open Windows, Dev Joneja ([e-mail])
  has written a menu/button client similar to xmenu; it's available via
  anonymous FTP from ftp.ncsa.uiuc.edu (141.142.20.50) as
  /outgoing/marca/epoch/xvmenu.tar.Z.

  Bob Weiner ([e-mail]) says the following concerning menus
  within Hyperbole:

  ----------------------------------------------------------------------
  If you use Hyperbole, you know what the Smart Key system is, context
  sensitive key bindings for many Emacs modes and subsystems.  There is
  a Smart Menu system that goes along with this but has not been
  released because it needs some additional menus and some integration
  work.  It is window manager and window system independent, works under
  Emacs, with a slightly customized version that can highlight selected
  menu items and display menus in a separate Epoch screen, and is
  written entirely in Elisp, so no patching is needed.  It provides much
  easier subsystem access for novices and experienced users and has been
  in use at a few sites for the last several years.

  I'd like to get it in a form for release but won't have the time for
  several months.  If an experienced Elisp programmer wanted to
  integrate it with Hyperbole and make any other changes, I [Bob, not
  Marc] would be willing to send it out and coordinate on and test the
  final changes.
  ----------------------------------------------------------------------

  See the list of FTP sites below for more information on Hyperbole.

*                          === KEYBOARD ===

F-1: How do I make the backspace key work properly?

  This is actually a GNU Emacs question, but it's included in this FAQ
  because it's probably more important to more people than all the
  other questions here.  (One of the great mysteries of GNU Emacs is
  why the backspace key _still_ doesn't do its job.)

  Here are four ways to fix this:

  METHOD #1:

  Put this in your .emacs file:

    (rebind-key "BackSpace" nil "\C-?")

  This is the cleanest Epoch-specific solution.  It rebinds
  the X representation for the backspace key directly to that
  of the delete key.

  [Thanks to Joe Wells ([e-mail]).]

  METHOD #2:

  Put this in your .emacs file:

    (global-set-key "\C-^bdc" 'backward-delete-char-untabify)
    (rebind-key "BackSpace" nil "\C-^bdc")

  This rebinds the X representation for the backspace key to the
  appropriate command for deleting a character backward.  Like the
  first method, this is Epoch-specific.

  If you don't like to have your backspace key also untabify (i.e.,
  convert tags to spaces on the fly), use this instead of the previous
  global-set-key:

    (global-set-key "\C-^bdc" 'backward-delete-char)

  METHOD #3:

  Put this in your .emacs file:

    (global-set-key "\C-h" 'backward-delete-char-untabify)
    (global-set-key "\C-xh" 'help-command) ; override mark-whole-buffer

  This makes C-h (the backspace key as well as the Control-h key
  sequence) delete characters backward, and shifts responsibility for
  help to C-x h.  This fix will work for GNU Emacs as well as Epoch.

  If you don't like to have your backspace key also untabify (i.e.,
  convert tabs to spaces on the fly), use this instead of the previous
  global-set-key for C-h:

    (global-set-key "\C-h" 'backward-delete-char)

  METHOD #4:

  Outside of Epoch, you can change the X representation of the
  BackSpace key into a Delete by doing this:

    xmodmap -e "keysym BackSpace = Delete"

  This approach has the disadvantage of not being done inside
  of Epoch for those who prefer customizing lisp code to
  customizing their system environments.

  [Thanks to Joe Wells ([e-mail]).]

F-2: How do I make the keys marked "Page Up" and "Page Down" on an IBM
 Selectric-style keyboard do their jobs?

  Using the key rebinding facility discussed below, you can put the
  following two lines in your .emacs file:

    (rebind-key "Prior" nil "\M-v") ; Note Prior, not Page Up.
    (rebind-key "Next" nil "\C-v")  ; Note Next, not Page Down.

  Similarly, if you want "Home" and "End" to go to the beginning and end
  of the current buffer respectively, do:

    (rebind-key "Home" nil "\M-<")
    (rebind-key "End" nil "\M->")

F-3: How do I bind keys in the numeric keypad on an IBM Selectric-style
 keyboard to their obvious functions (arrow movement, home, end, etc.)?

  Put these lines in your .emacs file:

    (rebind-key "KP_Home" nil "\M-<")
    (rebind-key "KP_Up" nil "\C-p")
    (rebind-key "KP_Prior" nil "\M-v")
    (rebind-key "KP_Left" nil "\C-b")
    (rebind-key "KP_Begin" nil "\C-l")
    (rebind-key "KP_Right" nil "\C-f")
    (rebind-key "KP_End" nil "\M->")
    (rebind-key "KP_Down" nil "\C-n")
    (rebind-key "KP_Next" nil "\C-v")

  NOTE: This makes the keypad arrow keys work, the keypad PgUp/PgDown
  work, and the keypad Home/End go to the beginning/end of the
  buffer.

  Other keys appropriate for rebinding in a Selectric-style numeric
  keypad include KP_Divide, KP_Multiply, KP_Subtract, KP_Add, KP_Enter,
  KP_Insert, and KP_Delete; see below for more details.

F-4: What general facilities does Epoch provide for rebinding function
 keys, and how do I use them?

  The rebind-key function allows you to rebind any keycode to a new
  string.  An example is probably best to show how this works.  To make
  the key marked "Page Up" (on IBM Selectric-style keyboards) actually
  move the current buffer up a page (like M-v), do:

    (rebind-key "Prior" nil "\M-v")

  Note that "Prior" is the actual X keysym name for the "Page Up" key;
  to see the X keysym names, refer to /usr/include/X11/keysymdef.h (or
  $OPENWINHOME/include/X11/keysymdef.h on OpenWindows systems).
  (Disregard the leading XK_ in keysymdef.h's definitions for Epoch's
  purposes; thus, X11's "XK_Prior" becomes Epoch's "Prior".  To find out
  which keys are actually active for your keyboard and server, use the
  command "xmodmap -pk".)

  The standard function keys are named F1 through F12, the function keys
  on the left side of a Sun-style keyboard are named L1 through L10, and
  so on.  The keypad apparently cannot be addressed by KP_0 through KP_9
  but must be referenced by names like KP_Left, KP_Up, and so on.

  A simple two-step approach for binding function keys to commands
  involves binding a key to an arbitrary GNU Emacs key encoding (in the
  following example, C-^ k 1) and then binding that encoding to the
  command.  An example that binds the function key marked "End" to an
  arbitrary command (in this case, end-of-line) follows:

    (rebind-key "End" 0 "\C-^k1")
    (global-set-key "\C-^k1" 'end-of-line)

  Note that the above is only an example of the two-step method; if you
  really want "End" to do 'end-of-line, do the obvious instead:

    (rebind-key "End" 0 "\C-e")

  The rebind-key command allows modifiers (e.g. shift, control) to be
  specified; the following example binds Control-"End" to an arbitrary
  command (in this case, end-of-buffer):

    (rebind-key "End" 'control "\C-^Ck1")
    (global-set-key "\C-^Ck1" 'end-of-buffer)

  For an example of these principles in action, see the file
  'amc/keys.el' in the 3.2 contrib directory (which is still up for
  anonymous ftp at cs.uiuc.edu as a separate .tar.Z file) or at
  ftp.ncsa.uiuc.edu in /outgoing/marca/epoch.

  [Thanks to Alan Carroll ([e-mail]).]

F-5: I want Epoch to disregard accidental presses of function keys that
 insert spurious characters (e.g., "-1~") into the buffer.  Does Epoch
 perchance have some magical way to make this happen?

  Perchance, Epoch does.  The variable epoch::function-key-mapping, if
  set to nil, makes Epoch disregard such keys, unless they're explicitly
  rebound with rebind-key.  You can set this in your .emacs file like
  so:

    (setq epoch::function-key-mapping nil)

  [Thanks to Alan Carroll ([e-mail]).]

F-6: How do I turn the keyboard bell off?

  The easy answer is to put the following line in your .emacs file:

    (setq epoch::bell-volume -50)

  Another possibility, if you like visual bells (i.e., having the
  entire edit window flash reverse video instead of hearing an audible
  beep), is to put the following in your .emacs file:

    (epoch::set-bell t)

  The malicious answer, for those who, like myself, never want to hear
  another beep for the rest of time, is to modify src/x11term.c in the
  Epoch distribution; just change the line that reads:

    XBell (xs->display,volume);

  To:

    /* XBell (xs->display,volume); */

  Then recompile.

*                        === HIGHLIGHTING ===

G-1: How do I highlight regions of text in a buffer with different styles?

  While the current Epoch distribution contain plenty of support for
  zones and styles, the enabling mechanisms that make syntax-directed
  highlighting possible, no intrinsic support for such highlighting is
  provided.  This situation may change in subsequent releases of Epoch.

  Three packages that provide varying degrees of support for
  syntax-directed highlighting are:

  tek-epoch-stuff-1.1.tar.Z (available from archive.cis.ohio-state.edu
  or ftp.ncsa.uiuc.edu, see below), which supports comment highlighting
  in source code as well as support for the Info documentation browser,
  various mail and news packages, and manual pages.

  marc-hilite.tar.Z (available from ftp.ncsa.uiuc.edu, see below), which
  is an extension to tek-epoch-stuff made by Yours Truly to allow
  per-mode regexp-based highlighting.  Thus, you can have all
  #define's/#endif's in red, setq's and defun's in green,
  int/float/double's in yellow, '-->'s in purple, and so on.
  (A very preliminary version of a reimplementation of marc-hilite,
  called Lightbrite, can be found here also; it includes partial
  documentation.  Hopefully Lightbrite proper will be completed
  sometime this summer.)

  hilit.el.Z (most recent version was posted to gnu.emacs.souces and is
  available from ftp.ncsa.uiuc.edu, see below), which provides
  source-code comment and regexp highlighting.

G-2: When I use one of the highlighting packages to highlight comments,
 why doesn't the mouse region selection style always take precedence
 over the comment style?

  This question refers to the following: if you highlight all comments
  in blue and the mouse region selection style is the default
  (underlining), the comments will be blue and not underlined when they
  are within the selection zone.

  For the full technical explanation, refer to the Epoch online info
  section entitled Epoch->Zones->Zone Plotting.  In short, Epoch has to
  have some way to decide which style takes precedence for a given
  character when that character is in two or more zones (since merging
  styles in that case is neither supported nor particularly logical).

  Essentially, the algorithm Epoch uses to decide which style is used
  will only have the 'proper' results (i.e., the underlining will take
  precedence) if the selected region lies entirely within a comment;
  the selected area will be underlined and the rest of the comment will
  be blue.  In a different case, e.g. if the selected region starts
  before the comment, the comment will be blue and not underlined even
  though it's selected.

  Following is a patch devised by Renaud Marlet
  ([e-mail]) that may be useful to people who
  want to try hacking Epoch's C source to make the drag style always
  come out on top; as usual, your mileage may vary.  (This patch will
  work as-is with 4.0b0 or later; if you're still using a 4.0 alpha
  level you'll have to change "drag-zone" to "drag-button".)

  -- BEGIN PATCH -----------------------------------------------------
  *** button.c.old        Sat Mar 28 01:55:11 1992
  --- button.c    Sat May  9 23:14:19 1992
  ***************
  *** 695,700 ****
  --- 695,709 ----
      register Lisp_Object buttons, next_b = Qnil;
      register int first = -1,last = -1;

  + #if 1
  +   /* DRAG-BUTTON */
  +   struct Lisp_Button *drag_button;
  +   Lisp_Object drag_button_value;
  +
  +   drag_button_value = XSYMBOL(intern("drag-zone"))->value;
  +   drag_button = XBUTTON(BUTTONP(drag_button_value) ? drag_button_value : Qnil);
  + #endif
  +
      /* Possible start in list */
      if (b_first) next_b = *b_first;
      if (NIL(next_b)) next_b = b->buttons;
  ***************
  *** 722,727 ****
  --- 731,742 ----
              if (b_end)    *b_end    = last;
              if (b_return) *b_return = buttons;
            if (b_first)  *b_first = buttons;
  +
  + #if 1
  +         /* DRAG-BUTTON */
  +         if (button == drag_button)
  +           return button->style;
  + #endif

              for (buttons2 = button->next; !NIL(buttons2); buttons2 = button2->next)
                {
  -- END PATCH -------------------------------------------------------

*               === EPOCH-SPECIFIC ELISP PACKAGES ===

H-1: Where can I find Epoch-specific elisp packages?

  Try the following anonymous FTP sites for Epoch-specific elisp
  packages:

  aix370.rrz.uni-koeln.de (134.95.132.2)
    /gnu/emacs

  archive.cis.ohio-state.edu (128.146.8.52)
    /pub/gnu/emacs/elisp-archive/elisp
    [This is main elisp-archive site; it is mirrored at
     ftp.uu.net (137.39.1.9) in /languages/elisp, among other places.
     Not much Epoch code exists here; in particular, a much more
     recent version of hilit.el.Z is at ftp.ncsa.uiuc.edu, below.]

  ftp.cs.buffalo.edu (128.205.32.3)
    /pub
    [This is the distribution site for the new Dired, which will
     be included in Emacs v19; it includes support for Epoch.]

  ftp.ncsa.uiuc.edu (141.142.20.50)
    /outgoing/marca/epoch
    [This is Yours Truly's archive of Epoch code; the
     README file gives an overview of what I consider to be
     'essential' Epoch packages, and all of those packages
     are available there.  If I get out of date on any of
     these and you notice it, please let me know.]

  icsi-ftp.berkeley.edu (128.32.201.55)
    /pub/elisp

  ireq-robot.hydro.qc.ca (131.195.2.130)
    /pub/emacs/lisp
    [This is the distribution site for the IMOUSE package.]

  wilma.cs.brown.edu (128.148.31.66)
    /pub/hyperbole
    [This is the distribution site for the Hyperbole hypertext
     system, which includes support for Epoch.  Also available
     separately from here is the wrolo 'rolodex' package, one of the
     components of Hyperbole.]

  Also see the contrib directory in the actual Epoch distribution.

  Also watch the gnu.emacs.sources Usenet newsgroup, as well as the
  epoch newsgroup/mailing list (see below).

  Please volunteer the names of any sites not on this list.

H-2: Where can I get a PostScript version of the Epoch manual?

  Use anonymous ftp to cs.uiuc.edu (128.174.252.1) in
  /pub/epoch-files/epoch; get epoch-4.0.epoch-man.ps.Z.

*                      === OTHER RESOURCES ===

I-1: What Epoch newsgroups/mailing lists are out there?

  The Usenet newsgroup gnu.epoch.misc and the mailing list
  [e-mail] are one and the same.  To join the mailing list,
  send a request to [e-mail].  (It is best to read the
  newsgroup if you have access to it, to save on network resources and
  the mailing list maintainer's time.)

  For more general information about Epoch and GNU Emacs, see the list
  of resources at the start of this file.

*                     === ADVANCED QUESTIONS ===

  [NOTE: This section is at the bottom since the questions involve actual
  source-code hacking or problems with specific machine configurations
  that Yours Truly cannot personally verify and whose solutions will
  probably involve some sort of hacking.]

Z-1: Under tvtwm, when I create a new screen, it is mapped relative to
 the origin on the virtual desktop, not the window I currently have on
 the desktop.  How do I fix this?

  This problem is present in Epoch4.0 beta level 0, although it appears
  to be fixed as of beta level 1.  The simple solution for beta level 0
  is to change the line in src/screen.c from

     size_hints.flags |= (gmask & (XValue|YValue)) ? USPosition : PPosition;
  to
     size_hints.flags |= PPosition;

  And set:

        UsePPosition "on"

  in your .twmrc or .tvtwmrc file.

  [From Philippe Bondono ([e-mail]).]

Z-2: Epoch 4.0b1 (or later) (as well as GNU Emacs 18.58) built under
 HP-UX 8.0 and 8.05 apparently don't recognize the Meta key as Alt.
 How can this be fixed?

  Bob Fisher ([e-mail]) suggests the following command,
  executed once per session, prior to starting Epoch:

          xmodmap -e "clear mod1"        \
                  -e "add mod1 = Meta_R" \
                  -e "add mod1 = Meta_L"

Z-3: Why do all of Epoch's colors go away when Epoch is run on an X11R5
 server with multiple screens?

  Dana Chee ([e-mail]) reports that X11R5 has a new
  SCREEN_RESOURCES property that allows/forces colors to only appear for
  color screens, but Epoch doesn't look at this property.  This bug
  will only bite you if you're running on a multi-screen system.  If it
  happens, there is a workaround; see the xrdb manpage and the xrdb
  option '-all'.

Z-4: Even though Epoch 4.0b1 includes fixes to keep the cursor from
 disappearing (as it does on occasion, especially in a shell, in
 Epoch 4.0b0), the cursor still disappears sometimes.  Is there a fix
 for this?

  First, Epoch 4.0p0 has additional fixes for this problem which
  presumably will supersede the fix given below.

  According to Michael Thome ([e-mail]), activating the XFlush
  code at the end of the CursorToggle routine in 4.0b1's x11term.c seems
  to fix the problem.  (In other words, '#if 0' on line 737 of x11term.c
  should be changed to '#if 1'.)

Z-5: I want Epoch to iconify itself immediately upon starting.  To this
 end, in my .emacs file I have (epoch::iconify-screen).  But most
 (~95%) of the time this doesn't work.  How can I make it work all the
 time?

  The technical explanation appears to be that the initial Epoch
  minibuffer and edit screen are unmapped after creation to set some
  properties for ICCCM purposes and then remapped, and this interferes
  with the iconification process.

  One workaround (that may or may not work for you) is to add a sit-for
  command to your .emacs file right before epoch::iconify-screen; for
  example:

    (sit-for 15)
    (epoch::iconify-screen)

  [Thanks to Bobby Bodenheimer ([e-mail]), Simon Kaplan
  ([e-mail]), and Chris Love ([e-mail]).]

Z-6: I'm running Epoch on an IBM RISC System/6000 under AIX 3.1 or 3.2
 and the arrow keys don't work.  How do I fix this?

  Marc's solution is to hack the Epoch source code; GNU Emacs and Epoch
  have, for a reason which I have not yet determined, decided to exclude
  AIX users specifically from those who are entitled to use arrow keys.
  Go into src/x11term.c and search for 'case KeyPress'.  Shortly
  thereafter you will see '#ifndef AIX'.  Remove this directive and its
  corresponding #endif, and the arrow keys will work.

  It should also be possible (although I have not tried it since I don't
  use RS/6000's currently) to rebind the arrow keys with rebind-key to
  C-n/C-p/C-b/C-f without modifying the source code.

Z-7: Every once in a while Epoch seemingly loses control of the mouse;
 I can no longer move from window to window or move the cursor within
 a window with the mouse.  How do I fix this?

  A temporary fix for this problem is to enter the following elisp code
  directly into Epoch (via M-x eval-expression):

    (setq epoch::event-handler 'event::handler)

  [Thanks to Chris Love ([e-mail]).]

*                        === CONTRIBUTORS ===

--> Thanks to the following people for contributing to this FAQ
    (whether knowingly or not :-) as well as anyone else I may have
    inadvertently forgotten to list:

  Bobby Bodenheimer ([e-mail])
  Philippe Bondono ([e-mail])
  Martin Boyer ([e-mail])
  Alan Carroll ([e-mail])
  Nhi Casey ([e-mail])
  Dana Chee ([e-mail])
  Alice Chen ([e-mail])
  Bob Fisher ([e-mail])
  Jerry Graves ([e-mail])
  Dev Joneja ([e-mail])
  Simon Kaplan ([e-mail])
  Tor Lillqvist ([e-mail])
  Chris Love ([e-mail])
  Simon Marshall ([e-mail])
  Rob McCool ([e-mail])
  Michael Thome ([e-mail])
  Bob Weiner ([e-mail])
  Joe Wells ([e-mail])

    Thanks particularly to Jerry Graves for much FAQ work.

    Thanks also to all the people who have spent time and effort
    developing Epoch and associated packages.
----------------------------------------------------------------------