SH-TK(1) SH-TK(1)
NAME
tk, chan, send, recv, alt - loadable tk module for sh.
SYNOPSIS
load tk
chan name...
send chan value
tk window title [ args... ]
tk winctl winid cmd
tk wintitle winid title
tk namechan chan [ name ]
tk del name
tk winid tkcmd
${tk window title [ args... ] }
${tk onscreen winid [ how ] }
${tk winid tkcmd }
${recv chan }
${alt chan ... }
DESCRIPTION
Tk is a loadable module for sh(1) that provides access to
Inferno Tk graphics and string channels. Most of the buil-
tin commands that it defines map closely to primitives
within wmlib(2) and tk(2). Unless otherwise stated, if a
command requires a winid argument, if no window with that id
is found, a bad win exception is raised. Similarly, a refer-
ence to an unknown channel name will raise a bad chan excep-
tion. There is no requirement that this module be used in a
windowing context: although window creation will fail if
there is no context, the channel communication primitives
will work regardless.
chan For each name in turn, chan creates a new channel
called name within the tk module. Name henceforth
represents a Limbo chan of string and can be used
to send string values between sh processes running
in parallel. A chan is also used to receive events
arriving from the window manager. It is illegal to
create a channel whose name consists entirely of
numeric digits.
send Send sends its argument value down the channel
chan, blocking until a corresponding receive oper-
ation takes place on the channel.
tk window Tk window creates a new top-level window with the
text of title in the titlebar at the top. Each
window created by the tk module is assigned a
unique numeric id. This id is printed by this
Page 1 Plan 9 (printed 11/21/24)
SH-TK(1) SH-TK(1)
command; to get access to the value of the winid
in a script, use ${tk window}. All the remaining
arguments are joined together by spaces and passed
as the tk options for the window. When a window
is created, a corresponding channel of the same
name is created. Events from the window manager
arrive on this channel, and should be responded to
appropriately using tk winctl.
tk onscreen
Tk onscreen must be called to make window winid
visible for the first time, the same as onscreen
in tkclient(2). How is the same as for that call -
if given, it must be one of place, onscreen or
exact.
tk winctl Tk winctl is used to communicate requests to the
window manager. (see winctl() in wmlib(2)). If an
event arriving on a window's channel is passed to
tk winctl, a suitable default action will take
place. The set of possible actions include:
exit A request to close the window.
size A request to resize the window.
task A request to miniaturise the window.
move A request to move the window.
tk wintitle
Tk wintitle changes the title of the window winid
to title.
tk del Tk del deletes a channel or a window. If name is
the winid of an existing window, then both the
window and its associated channel are destroyed.
A del of a non-existent channel or window is
ignored.
tk namechan
Tk namechan invokes the Tk module's namechan()
function to give a tk name to a channel within the
tk module. If name is omitted, then the tk name
given will be the same as chan.
tk winid If winid is the id of an existing window, the rest
of the arguments joined together by spaces and
sent as a tk command to be interpreted in that
window. If the shell is in interactive mode, then
the string returned by tk will be printed. The
exit status of tk is false if the string returned
Page 2 Plan 9 (printed 11/21/24)
SH-TK(1) SH-TK(1)
by tk begins with a bang (!) character.
${tk window}
Tk window is the same as its command counterpart,
except that it yields the winid of the newly cre-
ated window rather than printing it.
${tk winid}
This command is the same as its command counter-
part, except that it yields the return value from
the Tk command as its result.
${recv} Recv receives a string value from chan and yields
that value. It will block until a corresponding
send operation takes place on the channel.
${alt} Alt waits until a value is available on any of the
named chans. It yields a list containing two ele-
ments, the name of the channel from which the
value was received, and the actual value received.
EXAMPLE
The following code creates a window and allows normal window
manager operations on it. Another shell in a new process
group is created in order to prevent the shell window from
disappearing when the tk window is deleted.
sh
load std tk
pctl newpgrp
wid=${tk window 'My window'}
tk onscreen $wid
tk $wid update
while {} {tk winctl $wid ${recv $wid}} &
SOURCE
/appl/cmd/sh/tk.b
SEE ALSO
sh(1), sh-std(1), sh-expr(1), tkcmd(1), tk(2), tkclient(2),
wmlib(2), ``The Tk Reference Manual''
Page 3 Plan 9 (printed 11/21/24)