ZWGC(1)ZWGC(1)NAMEzwgc - Zephyr Windowgram Client program
SYNOPSISzwgc [ -reenter ] [ -nofork ] [ -ttymode ] [ -f filename ] [ -subfile
filename ] [ -default portname ] [ -disable portname ] ... [ output
driver options ] [ X Toolkit options... ]
DESCRIPTION
Zwgc is the main zephyr(1) client. It is responsible for receiving
selected zephyr notices on behalf of the user, formatting them, and
displaying them using one or more of the output devices.
Selection of Zephyr Notices
Zwgc subscribes to various notice classes and instances on behalf of
the user. Only notices in the subscription list will be received. The
subscription list is composed of the default subscriptions (stored on
the server), the user's subscriptions file, and any subscriptions made
using zctl(1). The user's subscription file defaults to
$HOME/.zephyr.subs, or it can be specified with the -subfile option.
If "-" is specified as the subscription filename, the subscriptions
will be read from standard input.
The zctl command is used to manipulate and change subscriptions. See
the zctl(1) man page for details.
Zephyr Description Files
Zwgc formats its output messages according to the commands in its
description file. The user's description file ($HOME/.zwgc.desc by
default, or whatever is specified by -f) is read, or the system file is
read if the user's does not exist.
Every time a notice is received, zwgc runs through the description
file, and executes the appropriate commands.
Zephyr Description File Syntax
A description file is simply a list of commands. Whitespace (spaces,
tabs, and line breaks) is used to separate tokens. The type and amount
of whitespace separating tokens is irrelevant. Comments can be delim‐
ited by # and newline (for line-oriented comments, e.g. "# this is a
comment" on a line by itself) or by /* and */ (e.g. "/* this is a com‐
ment */").
DESCRIPTION LANGUAGE
Expressions
Expressions are used by certain commands. They are composed from
string literals, variable references, function calls, and operators.
Parentheses can be used anywhere in an expression to group expressions
or increase readability.
String literals are specified by putting the contents in "double
quotes".
Variables are set using the set command (see "COMMANDS", below). They
are referenced in an expression by using the form $varname. Some vari‐
ables are set by default for each notice. All other variables retain
their values between notice interpretations, so that if you set a vari‐
able, it retains that value until later modified.
Functions are called using a C-like syntax, fname(expr1,expr2), where
fname is the function name and exprn are the arguments.
Binary operators use infix notation, such as "a == b".
Some commands use an expression list (exprlist), which is simply a set
of expressions separated by whitespace (e.g. $var1 "lit1" $var2).
Default variables
The following variables are always available:
1, ...
Numeric variables are assigned values corresponding to that field
in the notice (the body of each notice is conceptually an array of
fields, each terminated with a null character). If the number is
greater than the number of fields actually in the notice, the
value is "". For example, the standard zwrite messages have two
fields: $1 is the signature, and $2 is the text of the message.
auth An indication of the authenticity of the notice. ``yes'' means
the notice is authentic, ``no'' means it is not, and ``forged''
means that the message claimed to be authentic but the verifica‐
tion of the claim failed. The ``forged'' indication usually
appears when a user has changed his Kerberos tickets with kinit(1)
but has not run ``zctl sub'' to register this change with the
Zephyr servers.
class
The class of the current notice.
date The date on which the notice was sent.
default
The default output format for the current notice
error
An error message from the port read/write commands.
fromhost
The full name of the host from which the notice appears to have
been sent. This is not fully reliable, as the information used to
determine this hostname is not guaranteed to be correct (even for
authentic messages).
fullsender
The notice sender's name, including the zephyr realm name.
instance
The instance of the current notice.
kind The kind of notice.
message
The full text of the message, with nulls converted to newlines.
number_of_fields
The number of fields in the message (a string representation of a
decimal number).
opcode
The opcode of the current notice.
output_driver
The name of the output driver in use.
port The port from which the notice was sent.
realm
The local zephyr realm.
recipient
The recipient for the current notice. If the notice is a multi‐
cast (sent to several people), the recipient is set to ``*''.
sender
Usually a shortened version of fullsender. If the realm of the
sender is equal to the realm of the recipient, sender omits the
realm name.
time The time of day at which the notice was sent.
user The full zephyr name of the user (e.g. marc@ATHENA.MIT.EDU).
version
The current version of zwgc.
zephyr_version
The protocol version of the notice.
All of these variables (except for error, output_driver, and version)
are re-set before each notice is processed.
Functions
Following is a list of functions available for use in the description
file.
buffer()
The contents of the current output buffer.
downcase(expr)
Returns the value of expr, converted to lower case.
get(expr)
Returns a line from the port named expr. If there is no text
waiting on the port (e.g. the program connected to the port has
not printed any output), this function will wait until it can read
a line of text from the port.
getenv(expr)
Returns the value of the environment variable expr, or the empty
string if it does not exist.
lany(expr1, expr2), rany(expr1, expr2)
Return a number of characters equal to the length of expr2 from
the beginning (lany) or end (rany) of expr1 (e.g.
lany("1234567890","foo") would return "123"). If expr1 is a vari‐
able reference, the variable is modified to remove the characters
returned. If expr2 is longer than expr1, the value of expr1 is
returned (and expr1 is set to "", if a variable).
lbreak(expr1, expr2), rbreak(expr1, expr2)
Expr2 defines a set of characters. The function returns the long‐
est initial (lbreak) or final (rbreak) string from expr1 composed
of characters not in this set (e.g. lbreak("characters", "tuv")
would return "charac"). If expr1 is a variable reference, the
variable is modified to remove the characters returned. If no
characters in expr2 are in expr1, then expr1 is returned (and
expr1 is set to "", if a variable).
lspan(expr1, expr2), rspan(expr1, expr2)
These functions are the negation of the break functions; the
returned string consists of characters in the set defined by expr2
protect(expr)
Returns a string which will be evaluated identically to expr, but
will not affect any surrounding environments. That is, any char‐
acters which could close outside environments are quoted, and any
environments in expr which are not closed at the end are closed.
substitute(expr)
Evaluates variable references of the form $variable in expr and
converts $$ to $.
upcase(expr)
Returns the value of expr, converted to upper case.
verbatim(expr)
Returns a string that will be displayed exactly as expr looks.
Anything which could be mistaken for an environment is quoted.
zvar(expr)
Returns the value of the zephyr variable expr, or the empty string
if it does not exist. [Zephyr variables can be set and examined
with zctl(1).]
Operators
Following is a list of operators which can be used in the description
file to compose expressions:
expr1 + expr2
String concatenation of expr1 and expr2
expr1 == expr2
True if the two expressions are equal, false otherwise.
expr =~ expr2
True if the regular expression pattern expr2 matches expr1.
expr1 !~ expr2
Negation of "=~".
expr1 != expr2
Negation of "=="
expr1 and expr2, expr1 & expr2
True if expr1 and expr2 are both true.
expr1 or expr2, expr1 | expr2
True if either of expr1 or expr2 are true.
! expr1, not expr1
The logical negation of expr1.
Commands
Following is a list of the commands usable in the description language:
appendport expr1 expr2
Creates a port called expr1. All output to the port will be
appended to the file expr2. There is no input. If the file is
created, its mode is set to read-write, owner only (no access for
others).
break
Exits the innermost if, case, or while block.
case expr1 [ ((match expr [,expr ...]) | default) commands ] ... endcase
Evaluates expr1. Then, each of the match expressions is evaluated in order. The
first time an expression matches expr1, then the body of commands under it is exe‐
cuted, and the rest of the case statement is skipped. This compare is case-insensi‐
tive. default always matches, so it should always appear as the last set of commands.
See the default description file for an example of use.
clearbuf
Clears the output buffer (see below for details on buffering).
closeinput expr
Closes the file associated with expr.
closeoutput expr
Sends an EOF (end-of-file) to the process if expr was a port created by execport, or
closes the file if it was created by outputport or appendport.
closeport expr
Closes both input and output of expr as defined above.
fields variable1 ...
sets the list of variables to be equal to the fields in the notice. If there are more
variables than fields, the extra variables are left empty.
exec exprlist
Executes a program without any input or output. A command named by exprlist is exe‐
cuted. Each expression is used as an argument to the program; the first expression
names the program (it may be either an absolute pathname, or a program name; the
user's PATH is searched to find simple program names).
execport expr1 exprlist
Creates a port called expr1. A command named by exprlist is executed, as described
above for exec. All output to the port is sent to the standard input of the process.
Reading from the port will return the standard output of the process.
exit Completes processing of the current notice. The remainder of the description file is
ignored after execution of this command.
if expr1 then commands1 [elseif expr2 then commands2] ... [else commandsn] endif
If expr1 evaluates to true, execute commands1, etc. [A conditional construct, similar to the constructs in
the C shell (csh).]
inputport expr1 expr2
Creates a port called expr1. All input from the port comes from the file expr2. There is no output.
noop does nothing
outputport expr1 expr2
Creates a port called expr1. The file expr2 will be truncated, or created if it does not exist. All out‐
put to the port will be appended to the file expr2. There is no input. If the file is created, its mode
is set to read-write, owner only (no access for others).
print expr1 ...
adds the values of the expressions to the current output buffer. The values of the expressions are sepa‐
rated by spaces in the output.
put [expr [exprlist]]
Sends data to a port. If expr is provided, then it is used as the port, otherwise the port used is the
port corresponding to the default output device. If exprlist is provided, the expressions in the list are
sent to the port, separated by spaces. If it is omitted, then the contents of the output buffer are sent
as the data.
set variable = expr
sets variable equal to expr. Variable can later be referenced by $variable.
show text endshow
Appends text to the output buffer. This command is special, because the string does not need to be
quoted. Whitespace at the beginning or end of the lines of text is ignored. The endshow must appear as
the first token on a line (it may only be preceded on that line by whitespace). Variable substitutions
and formatting commands (but not expressions or functions) are processed in the text. Example:
show
this is some text
from: $sender
endshow
while expr do statements endwhile
Executes statements until expr is false.
PORTS
Ports are an abstraction encompassing all I/O forms of which zwgc is capable. There are pre-existing output
ports corresponding to each of the output devices, and more ports can be created with the port commands
described above.
OUTPUT
The output is usually collected in the output buffer and saved until a put command sends the output to an out‐
put device (such as an X display or a terminal). The output buffer is implicitly cleared after each notice is
completely processed.
Output devices are implemented as output ports. A message is displayed in a device-dependent manner when a
string is output to the port corresponding to the output device. Formatting commands are embedded in the text
as @ commands of the form @command(text). Command names are case-insensitive and consist of alphanumeric char‐
acters and underscores. Valid brackets are () [] {} and <>. If the command name is empty (such as in
``@(foo)''), then a new environment with no changes is created (This is useful to temporarily change some
parameter of the output, such as the font).
The following output devices are supported:
stdout
Sends the string to standard output exactly as is.
stderr
Sends the string to standard error exactly as is.
plain
Sends the string with all formatting environments removed to standard output.
tty Does formatting on the message according to @ commands embedded in the text. The output, with appropriate
mode-changing sequences, is sent to the standard output. The appropriate characteristics of the display
are taken from the TERMCAP entry (see termcap(5)) for the terminal named by the TERM environment variable.
Supported @ commands are:
@roman Roman (plain) letters (turns off all special modes).
@b or @bold Bold letters. If not available, reverse video, else underline.
@i or @italic Italic letters (underlining, if available).
@beep "bl" termcap entry, else "^G" (beep the terminal); limited to once per message.
@l or @left left aligned
@c or @center center aligned
@r or @right right aligned
Other @-commands are silently ignored.
X Displays one window per string output to the port. The output is formatted according to @ commands embed‐
ded in the string. Supported @ commands are:
@roman turns off @italic and @bold
@b or @bold turns on boldface
@i or @italic turns on italics
@l or @left left aligned
@c or @center center aligned
@r or @right right aligned
@large large type size
@medium medium type size
@small small type size
@beep Ring the X bell (limited to once per message)
@font sets the current font to the font specified in the contents of the environment (e.g.
@font(fixed)). This will remain in effect for the rest of the environment (a tempo‐
rary change can be achieved by enclosing the font-change in an @(...) environment).
If the named font is not available, the font ``fixed'' is used instead.
@color sets the color to the color specified in the contents of the environment. The color
name should appear in the X color name database. This color will remain in effect for
the rest of the environment. If the named color is not available, the default fore‐
ground color is used.
Any other environment name not corresponding to the above environment names will set the current ``sub‐
style.''
The attributes of a given block of text are determined by any active environments, evaluated in the con‐
text of the current style and substyle.
The style is specific to each window. Its name has three dot (``.'') separated fields, which are by
default the values of the class, instance, and recipient variables, with all dots changed to underscores
(``_'') and all letters converted to lowercase. The style can be altered by setting the style variable.
Note that it must always have exactly two ``.'' characters in it.
The substyle is determined by @ commands in the message text.
Zwgc variables which the X output device reads are:
default_X_geometry
default geometry for notices, set from resources
X_geometry overrides geometry in resource file, if set
default_X_background
default background color for notices, set from resources
X_background overrides bgcolor in resource file, if set
style style, as described above
The expected geometry values are described below.
The fonts and color for a piece of text are determined by the styles defined in the X resources file. The
following resources relating to text style are used by zwgc:
zwgc.style.stylenames.geometry
geometry for messages of the specified style
zwgc.style.stylenames.background
background color for messages of the specified style
zwgc.style.stylenames.substyle.substylename.fontfamily
fontfamily name for the specified style and substyle
zwgc.style.stylenames.substyle.substylename.foreground
foreground color for the specified style and substyle
zwgc.fontfamily.fontfamilyname.size.face
specifies the fonts for a given fontfamily. size is one of small, medium, or large, and
face is one of roman, bold, italic, or bolditalic.
The best way to get started in customizing X resources for zwgc is to examine the default application
resources and other users' resources to understand how they specify the default appearance.
X RESOURCES
Other X resources used by zwgc are listed below. Entries like
zwgc*option: value
Zwgc*option: value
zwgc.option: value
*option: value
will work.
An entry labeled with zwgc*option in any of the sources takes precedence over Zwgc*option, which takes prece‐
dence over *option entries. The following sources are searched in order:
command-line arguments (-xrm)
contents of file named by XENVIRONMENT environment variable
X server resource database (see xrdb(1))
application resources file
Logical values can be ( Yes On True T ) or ( No Off False nil ).
OPTION: MEANING [default]:
cursorCode number of a code from the cursorfont (should be an even integer, see <X11/cursorfont.h>) to use
for the windows.
foreground Primary foreground color
Foreground Secondary foreground color (if foreground not set) [BlackPixel is the default if neither is set]
background Primary background color
Background Secondary background color (if background not set) [WhitePixel is the default if neither is set]
borderColor Primary border color
BorderColor Secondary border color (if borderColor not set) [BlackPixel is the default if neither is set]
pointerColor Primary mouse pointer color [foreground color is the default if not set]
reverseVideo (logical) Toggles foreground and background (and border, if it matches foreground or back‐
ground).
ReverseVideo Secondary toggle, if reverseVideo is not set. [off is the default if neither is set]
borderWidth Primary border width selector
BorderWidth Secondary border width selector (if borderWidth is not set) [1 is the default value if neither
is set]
internalBorder Primary border between edge and text
InternalBorder Secondary selector (if internalBorder not set) [2 is the default value if neither is set]
geometry Primary POSITION (not size) geometry specifier. The geometry should be of the form
"{+|-}x{+|-}y", specifying an (x,y) coordinate for a corner of the window displaying the notice.
The interpretation of positive and negative location specifications follows the X conventions.
A special location of `c' for either x or y indicates that the window should be centered along
that axis. Example: a geometry of "+0+c" specifies the window should be at the top of the
screen, centered horizontally.
Geometry Secondary position specifer. [+0+0 is the default if neither is set.]
resetSaver (logical) Primary value to force screen to unsave when a message first appears.
ResetSaver (logical) Secondary value to force screen to unsave. [default True]
reverseStack (logical) Primary value to specify that zwgc should attempt to stack WindowGram windows such
that the oldest messages normally show on top. Some X window managers may silently ignore
zwgc's attempts to restack its windows. This option can cause some unusual interactions with
other windows if the user manually restacks either the other windows or the WindowGram windows.
ReverseStack Secondary value to enable reverse stacking. [default False]
title (string) Primary window title
Title Secondary window title [defaults to the last pathname component of the program name, usually
"zwgc"]
transient (logical) Primary value which determines if zephyrgram windows will be created with the WM_TRAN‐
SIENT_FOR property set. If this resource is true, the property will be set, telling certain
windowmanagers to treat zephyrgram windows specially. For instance, twm will not put decora‐
tions on transient windows, mwm will not let you iconify them, and uwm ignores the resource
entirely.
Transient Secondary transient determining value [default False]
enableDelete (logical) If true, zwgc creates a WM_PROTOCOLS property on all zgrams, with WM_DELETE_WINDOW as
contents.
EnableDelete Secondary value to enable WM_DELETE_WINDOW protocol on zgrams [default False]
minTimeToLive Primary value which specifies the minimum amount of time (``minimum time to live'') a WindowGram
must be on-screen (in milliseconds) until it can be destroyed. This feature is useful to avoid
accidentally clicking on new WindowGrams when trying to delete old ones.
MinTimeToLive Secondary value of ``minimum time to live.''
iconName (string) Primary icon name
IconName Secondary icon name [defaults to the last pathname component of the program name, usually
"zwgc"]
name (string) Primary window class name
name Secondary window class name [defaults to the last pathname component of the program name, usu‐
ally "zwgc"]
synchronous (logical) Primary X synchronous mode specifier. On means to put the X library into synchronous
mode.
Synchronous Secondary X synchronous mode specifier. [default is `off']
The window class is always "Zwgc".
X BUTTONS
Clicking and releasing any button without the shift key depressed while the pointer remains inside a WindowGram
window will cause it to disappear. If the pointer leaves the window while the button is depressed, the window
does not disappear; this provides a way to avoid accidentally losing messages.
If the control button is held down while clicking on a WindowGram, then that WindowGram and all windowgrams
under the point where the button is released will be erased.
WARNING: If you do this with too many WindowGrams under the mouse, it is possible for your subscriptions to be
lost. If zctl retrieve returns nothing, then issue a zctl load command to re-subscribe to your default set of
subscriptions. If you use znol, then znol -q & will restore the subscriptions you need for znol.
Portions of the text of a message may be selected for "pasting" into other X applications by using the shift
key in cooperation with the pointer buttons. Holding the Shift key while depressing Button1 (usually the left
button) will set a marker at the text under the pointer. Dragging the pointer with Shift-Button1 still
depressed extends the selection from the start point, until the button is released. The end of the selection
may also be indicated by releasing Button1, holding down the Shift key, and pressing Button3 (usually the right
button) at the desired endpoint of the selection. The selection will appear with the text and background col‐
ors reversed.
ADDITIONAL X FEATURES
If zwgc receives a WM_DELETE_WINDOW, it destroys the zephyrgram as if it were clicked on.
If a zephyrgram is unmapped, it is removed from the stacking order used by reverseStack.
COMMAND LINEzwgc is normally invoked from /usr/athena/lib/init/login, $HOME/.xsession, or /usr/athena/lib/init/xsession in
the foreground and with no arguments. When it has successfully set your location, it will put itself into the
background (unless the -nofork option has been specified). At this point it is safe to invoke additional zephyr
commands, such as znol(1). (You can also put these commands in the initprogs Zephyr variable; the value of
this variable is passed as the argument to the system(3) library call during initialization.) zwgc will exit
with an exit status of 0 if it was able to open the X display successfully or 1 if it couldn't open the display
and the Zephyr variable fallback was set to ``false''. If fallback is set to ``true'', zwgc will fall back to
``ttymode'' (making the tty driver the default output device) if it can't open the X display. If fallback is
not set and the display cannot be opened, zwgc prints an explanatory message and exits with a status of 1.
If the -ttymode option is specified, zwgc will ignore any X display and use the terminal as its primary output
device. This flag overrides any setting of the fallback variable.
The -reenter option is provided for compatibility with the previous version of zwgc.
zwgc will exit cleanly (unset location and cancel subscriptions) on:
SIGTERM
SIGHUP
XIOError (with a message to stderr)
SIGHUP is what it expects to get upon logout. Also, the signals SIGINT, SIGQUIT, and SIGTSTP are ignored
because they can be sent inadvertently, and bizarre side-effects can result. If you want them to be acted on,
then run zwgc-nofork &
CONTROL MESSAGES
In order to allow some special user controls over the behavior of zwgc, certain Zephyr control notices can be
sent directly to zwgc using the zctl(1) program. Currently implemented controls are
wg_read tell zwgc to re-read the current description file.
wg_shutdown tell zwgc to cancel all subscriptions and stop acting on incoming notices. zwgc saves the sub‐
scriptions that were in effect at the time of the shutdown so that it can restore them later if
needed.
wg_startup tell zwgc to restart from being shutdown and reinstall the saved subscriptions.
Other control messages may be implemented in the future.
EXAMPLES
For an example of a description file, see /usr/athena/lib/zephyr/zwgc.desc. For an example of X resources, see
/usr/athena/lib/zephyr/zwgc_resources.
BUGS
The X selection code can highlight the wrong portions of messages containing formatted text placed with the
@center() or @right() directives.
FILES
$HOME/.zwgc.desc
Default location of user's description file
/usr/athena/lib/zephyr/zwgc.desc
System-wide description file
/usr/athena/lib/zephyr/zwgc_resources
Default X application resources.
$HOME/.zephyr.vars
File containing variable definitions
$HOME/.zephyr.subs
Supplementary subscription file
$HOME/.Xresources
Standard X resources file
$WGFILE or /tmp/wg.uid
File used to store WindowGram port number for other clients
SEE ALSOcsh(1), kinit(1), xrdb(1), zctl(1), zephyr(1), znol(1), X(1), getenv(3), system(3), termcap(5), zephyrd(8),
zhm(8)
Project Athena Technical Plan Section E.4.1, `Zephyr Notification Service'
AUTHORS
John Carr (MIT/Project Athena) <jfc@athena.mit.edu>
Marc Horowitz (MIT/Project Athena) <marc@athena.mit.edu>
Mark Lillibridge (MIT/Project Athena) <mdl@CS.CMU.EDU>
RESTRICTIONS
Copyright (c) 1989 by the Massachusetts Institute of Technology. All Rights Reserved.
zephyr(1) specifies the terms and conditions for redistribution.
MIT Project Athena November 30, 1989 ZWGC(1)
