zwgc - Online in the Cloud

PROGRAM:

NAME

zwgc - Zephyr Windowgram Client program

SYNOPSIS

zwgc [ -reenter ] [ -nofork ] [ -ttymode ] [ -f filename ] [ -subfile filename ] [ -loc
text ] [ -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 delimited 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
comment */").

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 variables are set by default for each
notice. All other variables retain their values between notice interpretations, so that
if you set a variable, 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 verification 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 multicast (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. [email protected]).

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 variable 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 longest 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 characters 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.

stylestrip(expr)
Returns expr with all environments stripped out.

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.

expr1 =~ 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
executed, and the rest of the case statement is skipped. This compare is case-
insensitive. 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
executed. 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 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).

print expr1 ...
adds the values of the expressions to the current output buffer. The values of the
expressions are separated 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 output 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 characters 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 embedded 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 temporary 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
foreground color is used.

Any other environment name not corresponding to the above environment names will set
the current ``substyle.''

The attributes of a given block of text are determined by any active environments,
evaluated in the context 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
.option: value

will work.

An entry labeled with zwgc*option in any of the sources takes precedence over Zwgc*option,
which takes precedence 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 background).

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_TRANSIENT_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 decorations
on transient windows, mwm will not let you iconify them, and uwm ignores
the resource entirely.

Transient Secondary transient determining value [default False]

allDesktops (logical) Primary value which determines if zephyrgram windows should
appear on all desktops, for those window managers which support multiple
desktops (sometimes referred to as workspaces). When this resource is true
(the default), zwgc sets the _NET_WM_DESKTOP property to 0xFFFFFFFF for
each zephyrgram window, indicating that it should appear on all desktops.

AllDesktops Secondary value determining whether zephyrgram windows should appear on all
desktops.

scrollDelete (logical) If true, scrolling over a zgram will cause it to be deleted

ScrollDelete Secondary value to enable deletion of a zgram by scrolling over it [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, usually "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 colors 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 LINE

zwgc is normally invoked from $HOME/.xsession in the foreground. When it has successfully
set your location and obtained subscriptions, 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.

If the -loc option is specified, zwgc will use the specified string as the tty field for
the location it sets. This allows users to potentially specify more useful auxiliary
information than their ttys or display names.

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 &

If zwgc receives a SIGUSR1, it will rewrite the file used to store the WindowGram port
number ($WGFILE or /tmp/wg.uid), in the event that the file has been lost.

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 subscriptions 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 /etc/zephyr/zwgc.desc. For an example of X
resources, see /etc/zephyr/zwgc_resources.

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