In the following example, we have an application which has the following sources of configurable information:
- hard coded value of "None" for the label for the button
- resource file (called {programName}.def) which might be shipped along with the application and would be installed in the same directory as the application, allowing a site administrator to set site wide defaults for the application
- user provided app-defaults file which allows the user to customize personal preferences
- command line argument permitting a per invocation unique value setting
#! /usr/tcl84/bin/tclsh
package require Tk
proc listResources { w } {
set retval {}
set head [tk appname]$w
foreach tuple [$w configure] {
if { [llength $tuple] == 5 } {
lappend retval $head.[lindex $tuple 1]
}
}
return $retval
}
option add *currentValue "None" widgetDefault
# Pick up resources installed with application
set scriptDir [file dirname [info script]]
puts "scriptDir = $scriptDir"
set programName [file tail $argv0]
set defaultResources [file join $scriptDir $programName.def]
puts "defaultResources = $defaultResources"
catch {option readfile $defaultResources startupFile }
# Pick up user defined resource file
set userDefaults [file join $::env(HOME) "app-defaults" $programName]
puts "userDefaults = $userDefaults"
catch {option readfile $userDefaults userDefault }
set b [button .button1 -textvariable currentValue -command [list exit]]
if { $::argc > 0 } {
if { [lindex $::argv 0] == "-currentValue" } {
option add *currentValue [lindex $argv 1] 70
}
}
set currentValue [option get $b currentValue {}]
puts "currentValue = $currentValue"
pack $b
# Uncomment these lines to display the resources used by the $b widget
# foreach i [listResources $b] {
# puts [format "%s: %s" $i [option get $b $i {} ]]
# }
