namespaces - how do I update a variable via a tk window by name -

consider following situation:

namespace eval ::mydialog {}  proc ::mydialog::show {w varname args} {     upvar 1 $varname thevar    # can access thevar     # (1)     # code defining/creating window    # here widgets user interaction created,     #   of call ::mydialog::_somecallback     wm protocol $w  wm_delete_window [list ::mydialog::close $w] }  proc ::mydialog::_somecallback {}  {    # how access thevar here?     # (2) }  proc ::mydialog::close { w } {    # here changes supposed written varname in calling scope,    #    how do that?!     # (3)     destroy $w } 

im trying figure out how (a) variable calling scope (b) have available in 3 procs , (c) writing changes said variable.

(a) solve using 'upvar 1 $varname thevar' (b) solve namespace variable (c) long have 1 proc happen automaticly (a) due fact working on local alias of variable

the problem upvar works (at least intended) in (1). use upvar in (1) , save/copy namespace variable, solve (a) , (b), not (c).

i gratefull if point me in right direction here.

also, i'm relativly new tcl/tk concept might not ideal, suggestions toward better design welcome too.

i suggest use namespace variable keeps name of variable, , upvar using global scope.

namespace eval ::mydialog {     variable varname }  proc ::mydialog::show {w _varname args} {      variable varname $_varname     upvar #0 $varname thevar  }  proc ::mydialog::_somecallback {}  {     variable varname     upvar #0 $varname thevar     puts $thevar }  proc ::mydialog::close { w } {     variable varname     upvar #0 $varname thevar     set thevar newval }  set globalvar oldval # => oldval ::mydialog::show {} globalvar ::mydialog::_somecallback # => oldval ::mydialog::close {} # => newval puts $globalvar # => newval 

note syntax highlighting fails: #0 $varname thevar isn't comment.

this works namespace variables too: if have variable called nsvar in ::foobar namespace can use this:

set ::foobar::nsvar oldval ::mydialog::show {} ::foobar::nsvar ::mydialog::_somecallback ::mydialog::close {} puts $::foobar::nsvar 

with same effects.

you can't, however, use variables local procedure way.

one way make simple use snit widgets instead of collections of tcl procedures.

documentation: namespace, proc, puts, set, upvar, variable

snit documentation: man page, faq (the faq serves kind of introduction well)