Tornado

3
Launcher
This sort of safeguard is nearly universal in graphical applications, but some
people find it annoying. If you would prefer to take your chances with an
occasional unintended shutdown, for the sake of having the launcher obey you
unquestioningly, this example may be of interest. It shows how to redefine the Quit
command to shut down the launcher without first displaying a query.
To discover what procedure implements the Quit command, examine the launcher
definitions in ${WIND_BASE}/host/resource/tcl/Launch.tcl. Searching there for the
string “Quit” leads us to the following menuButtonCreate invocation, which
shows that the procedure to redefine is called launchQuit:
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menuButtonCreate File Quit Q {launchQuit}
Example 3-2
Alternate Quit Definition
The following redefinition of the launchQuit procedure eliminates the safeguard
against leaving the launcher accidentally:
#############################################################################
#
# launchQuit - abandon the launcher immediately
#
# This routine is a replacement for the launchQuit that comes with the
# launcher; it runs when Quit is selected from the File menu in place of
# the standard launchQuit, to avoid calling a confirmation dialog.
#
# SYNOPSIS:
# launchQuit
#
# RETURNS: N/A
#
# ERRORS: N/A
#
proc launchQuit {} {
exit
}
An Open Command for the File Menu
Because editing files is a common development activity, it may be useful to invoke
an editor from the launcher. This example defines a File>Open command to run the
editor specified by the EDITOR environment variable. The example is based on the
file selector built into the noticePost Tcl extension.
The code in this example collects the launcher initialization (adding commands to
the File menu, both for this example and for Example 3-1) in an initialization
procedure. In the example, the launcher executes launchExtInit, which adds
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