.\"	$Source$
.\"	$Author$
.\"	$Id$
.TH ZWGC 1 "November 27, 1989" "MIT Project Athena"
.SH NAME
zwgc \- Zephyr Windowgram Client program
.SH SYNOPSIS
.B zwgc
[ -f
.I filename
]
[ -subfile
.I filename
]
[ -default
.I portname
]
[ -disable 
.I portname
] ... [output driver options] [ X Toolkit options... ]
.SH DESCRIPTION
.I Zwgc
is the main
.I zephyr(1)
client.  It is responsible for receiving selected zephyr notices on
behalf of the user, formatting them, and then outputting them using
one or more of the output devices.

.PP
.B Selection of Zephyr Notices

.PP 
.I 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 \fIzctl(1)\fR.  The user's subscription file is
/fI$HOME/.zephyr.subs/fR, or it can be specified with the -subfile
option.  If - is specified as the subscription filename, the
subscriptions will be read from standard input.

.PP
The \fIzctl\fR command is used to manipulate subscriptions and
to change subscriptions.  See the \fIzctl(1)\fR man page for details.

.PP
.B Zephyr Description Files

.PP
.I Zwgc
formats its output messages according to the commands in its
description file.  The user's description file (\fB$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.

.PP
.B Zephyr Description File Syntax

A description file is simply a list of commands.  Whitespace is used
to separate tokens, what kind and how much is irrelevant.  Comments
can be delimited by # and newline or by /* and */.

EXPRESSIONS

Expressions consist of variable references, function calls, and
operators.  Variables are set using the \fBset\fR command.  They are
referenced in an expression by using the form $\fIvarname\fR.  Some
variables are set by default for each zephyrgram.
Functions are called using a C-like syntax,
\fBfname\fR(\fIexpr1\fR,\fIexpr2\fR), where \fBfname\fR is the
function name and \fIexpr\fRn are the arguments.  Binary operators use
infix notation.  Parenthesis can be used anywhere in an expression to
group expressions or increase readability.

Default variables

zephyr_version
The current version of \fIzwgc\fR

class

instance

opcode

default
The default output format for the zephyrgram

recipient
This is set to the recipent's name, or ``*'' for broadcast messages.

fullsender
The sender's name including the zephyr realm name

port
The port which the zephyrgram was sent from

kind

auth
``yes'', ``no'', or ``forged''

sender
fullsender, with the realm removed if it is equal to the realm of the
recipient.

time

date

fromhost
The hostname of the sender

message
The full text of the message, with nulls converted to newlines.


Functions

buffer()
The contents of the current output buffer

substitute(expr)
Evaluates variable references of the form \fI$variable\fR in expr and
converts $$ to $.

protect(expr)
Returns a string which will be evaluated identically to \fIexpr\fR,
but will not affect any surrounding environments.  That is, any
characters which could close outside environments are quoted, and any
environments in \fIexpr\fR which are not closed at the end are closed.

verbatim(expr)
Returns a string that will be displayed exactly as \fIexpr\fR looks.
Anything which could be mistaken for an environment is quoted.

getenv(expr)
Returns the value of the environment variable \fIexpr\fR, or the empty
string if it does not exist.

upcase(expr)

lowercase(expr)

zvar(expr)
Returns the value of the zephyr variable \fIexpr\fR, or the empty
string if it does not exist.

get(expr)
Returns a line from the port named \fIexpr\fR.  This call will block.

.HP
.BI "lbreak(" expr1 ", " expr2 ")"
.HP
.BI "rbreak(" expr1 ", " expr2 ")"
.br
.I Expr2
defines a set of characters.  The function returns the longest
initial
.RB ( lbreak )
or final 
.RB ( rbreak )
string from
.I expr1
composed of characters not in this set.  If 
.I expr1
is a variable reference, the variable
is modified to remove the characters returned.  If no characters
in
.IR expr2 " are in " "expr1, expr1 "
is returned, then set to "" (if a variable).
.HP
.BI "lspan(" expr1 ", " expr2 ")"
.HP
.BI "rspan(" expr1 ", " expr2 ")"
.br
This is the negation of
.B span;
the returned string consists off all characters in the set defined by
.I expr2
.B Operators
.RS .5i
.HP
.IB expr1 " + " expr2
.br
Concatenation of
.IR expr1 " and " expr2
.HP
.IB expr1 " == " expr2
.br
True if the two exprs are equal, false otherwise.
.HP
.IB expr " =~ " expr2
.br
True if regexp pattern
.IR expr2 " matches " expr1.
.HP
.IB expr1 " !~ " expr2
.br
Negation of "=~".
.HP
.IB expr1 " != " expr2
.br
Negation of "=="
.HP
.IB expr1 " and " expr2
.HP
.IB expr1 " & " expr2
.br
True if
.IR expr1 " and " expr2
are both true.
.HP
.IB expr1 " or " expr2
.HP
.IB expr1 " | " expr2
.br
True if either of
.IR expr1 " and " expr2
are true.
.HP
.BI "! " expr1
.br
The logical negation of
.I expr1.

PORTS

Ports are an abstraction which puts together all forms of I/O which
zwgc can do.  There are prexisting output ports corresponding to each
of the output devices, and more ports can be created with the
port commands described below.  It is important to realize that the
output devices are also implemented as ports.

COMMANDS

noop
does nothing

set variable = expr
sets \fIvariable\fR equal to \fIexpr\fR

fields variable ...
sets the list of variables to be equal to the fields in the
zephyrgram.  If there are more variables than fields, the extra
variables are left empty.

print expr ...
adds the values of the expressions to the current output buffer,
separated by one space.

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 a line is ignored, and there must be only whitespace before 
the \fIendshow\fR.  Variable substitutions and formatting commands
(but not expressions or functions) happen.

clearbuf
Clears the output buffer.

appendport expr1 expr2
Creates a port called \fIexpr1\fR.  All output to the port will be
appended to the file \fIexpr2\fR.  There is no input.

execport expr1 exprlist
Creates a port called \fIexpr1\fR.  A command named by \fIexprlist\R
is forked, and all output to the port will go to the standard input
of the process.  Reading from the port will return the standart output
of the process.

inputport expr1 expr2 
Creates a port called \fIexpr1\fR.  All input from the port come from
the file \fIexpr2\fR.  There is no output.

outputport expr1 expr2
Creates a port called \fIexpr1\fR.  The file \fIexpr2\fR will be
truncated, or created if it does not exist. All output to the port
will be appended to the file \fIexpr2\fR.  There is no input.

closeinput expr
Closes the file associated with \fIexpr\fR.

closeoutput expr
Sends an EOF to the process if \fIexpr\fR was a port created by
execport, or closes the file if it was created by closeport or
appendport.

closeport expr
Closes input and output of \fIexpr\fR as defined above.

put [expr [exprlist]]
Sends data to a port.  The default data if no expressions are given is
the output buffer.  The default port if no port is specified is the
port corresponding to the default output device.

exec exprlist
Execs a program without any input or output.

if expr then commands [elseif expr then commands] ... [else commands] endif

case expr1 [ ((match expr ...) | default) commands ] ... endcase
Evaluates \fIexpr1\fR.  Then, each of the match expressions is
evaluated in order.  The first time an expression matches \fIexpr1\fR,
then the body of commands under it is executed.  default always
matches, so it should go at the end.

while expr do statements endwhile
Executes \fIstatements\fR until \fIexpr\fR is true.

break
Exits the innermost if, case, or while block.

exit
Completes processing of the current zephyrgram.


.SH OUTPUT
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 \fB@(foo)\fR), then a new
environment with no changes is created.  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 appropriate characteristics of the display are taken from
the TERMCAP entry for that tty (see \fItermcap(5)\fR.  Supported @
commands are:
   @center	center
   @em		Emphasis.  User underline if available, else reverse video.
   @bold	Bold letters.  If not available, reverse video, else underline.
   @bell	"bl" termcap entry, else "^G"
   @blink	"mb"/"me" termcap entry, else nothing.
   @rv		"so"/"se" termcap entry.
   @u		"us"/"ue" termcap entry.
   @l or @left		left aligned
   @c or @center	center aligned
   @r or @right		right aligned

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
	@large		large type size
	@medium		medium type size
	@small		small type size
	@beep		beeps once
	@font		sets the font.  This will remain in effect for
			the rest of the environment.
	@color		sets the color.  This will remain in effect for
			the rest of the environment.

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.  It has three .
separated fields, which are the class, instance, and recipient of the
message by default.  It can be set by setting the \fIstyle\fR zwgc
variable.  Note that it \fBmust always\fR have exactly two .
characters in it.  The substyle is determined by as above by @
commands in the message text.

Zwgc variables which the X output device can read are:

	default_X_geometry	default geometry for zgrams
	X_geometry		overrides geometry in resource file
	default_X_bgcolor	default background color for zgrams
	X_bgcolor		overrides bgcolor in resource file

The fonts and color for a piece of text are determined by the styles
defined in the X resources file.  The following resources are
understood
by zwgc:

zwgc.style.\fIstylenames\fR.geometry
	geometry for messages of the specified style

zwgc.style.\fIstylenames\fR.background
	background colorfor messages of the specified style

zwgc.style.\fIstylenames\fR.substyle.\fIsubstylename\fR.fontfamily
	fontfamily name for the specified style and substyle

zwgc.style.\fIstylenames\fR.substyle.\fIsubstylename\fR.foreground
	foreground color for the specified style and substyle

zwgc.fontfamily.\fIfontfamilyname\fR.\fIsize\fR.\fIface\fR
	specifies the fonts for a given fontfamily.  \fIsize\fR is one
	of small, medium, or large, and \fIface\fR is one of roman,
	bold, italic, or bolditalic.

If you think this is all confusing, you're right.  The best thing to
do is to look at the default files and the desc and resource files of
people who seem to know what's going on.

.B raw
No processing is performed on the output.

.SH FILES
.nf
~/.zwgc.desc
~/.zephyr.vars
~/.zephyr.subs
~/.Xresources
/usr/athena/lib/zephyr/zwgc_resources
/etc/athena/zwgc.desc
.fi
.SH SEE ALSO
zctl(1), zephyr(1), znol(1), zephyrd(8), zhm(8), X(1)
.br
Project Athena Technical Plan Section E.4.1, `Zephyr Notification Service'
.SH AUTHORS
.br
John Carr
.br
Marc Horowitz
.br
Mark Lillibridge
.sp