Dear all, Katherine's issue is one I've run across several times, so I used this as an excuse to figure it out for myself once and for all. I thought others might be interested, so I summarized a couple of things about it: The Problem: When you create an entry in Tcl/Tk, you associate a Tcl variable with it. The problem arises when you want to use that variable to do something from within a proc (proc's are subroutines in Tcl) and the entry was made in a different proc.

The problem is that variables are local by default so you need to either pass them or somehow share them with proc's There are two ways to do this: Real lazy way: Build all your entry widgets in your main routine so they are global by default (makes for messy code, but OK for simple things) Simple way: Just declare the variable as global in the procs that it is used in. NOTE: You can not use global if you are using namespaces The Right Way: The proper way to do this is to place your entire routine into a namespace Once you have done that, any time you reference a variable that is shared across proc's you prefix it with namespace:: This is the "right way" because you don't have to worry about overwriting a global variable that someone else defined. However, I hate typing namespace:: on everything so I have never gotten used to using this method. Here is an example with name spaces: #--------------------------------------------------------------------------- ----------------------- namespace eval exmp1 { set t .exmp1 catch {destroy $t} toplevel $t label $t.msg -text "Enter Something" -padx 2m -pady 2m entry $t.entry -relief sunken -textvariable exmp1::myVar button $t.okBut -text "OK" \ -command exmp1::doOK # -command [ namespace code [list doOK] ] pack $t.msg pack $t.entry pack $t.okBut proc doOK {} { puts $exmp1::myVar destroy $exmp1::t } } #--------------------------------------------------------------------------- ----------------------- If you want to use globals: #--------------------------------------------------------------------------- ----------------------- proc bldIt {} { global t myVar label $t.msg -text "Enter Something" -padx 2m -pady 2m entry $t.entry -relief sunken -textvariable myVar button $t.okBut -text "OK" -command doOK pack $t.msg

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pack $t.entry pack $t.okBut } proc doOK {} { global t myVar puts $myVar destroy $t } set t .exmp2 catch {destroy $t} toplevel $t bldIt #--------------------------------------------------------------------------- ----------------------- If you look closely at the last example, you will note that the widgets are built in a proc. If you build your widgets in the main routine, AND you don't use namespaces, you don't need the globals: #--------------------------------------------------------------------------- ----------------------- set t .exmp2 catch {destroy $t} toplevel $t label $t.msg -text "Enter Something" -padx 2m -pady 2m entry $t.entry -relief sunken -textvariable myVar button $t.okBut -text "OK" -command doOK pack $t.msg pack $t.entry pack $t.okBut proc doOK {} { puts $myVar destroy $t } #--------------------------------------------------------------------------- ----------------------- I hope this is helpful Eric ------------------------------------------------------------------------- Eric Miller Director, CAD & Software Services Phoenix Analysis & Design Technologies (480) 813-4884, x103 www.padtinc.com ----------------------------------------------------------------- TO SUBSCRIBE: send blank email to xansys-subscribe@yahoogroups.com TO UNSUBSCRIBE: send blank email to xansys-unsubscribe@yahoogroups.com ARCHIVED on: http://www.groups.yahoo.com/messages/xansys Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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