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 builtin 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 reference to
an unknown channel name will raise a
bad chan
exception.
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 operation
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 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.
TP
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 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 created window rather than printing
it.
${tk winid}
This command is the same as its command counterpart,
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 elements,
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.