VMD-L Mailing List

From: Thomas Evangelidis (te8624_at_mbg.duth.gr)
Date: Sun Dec 21 2008 - 21:00:38 CST

Dear Tcl/Tk programmers,

I'm preparing a GUI to incorporate it into VMD in the context of a new
plugin. I
have a problem related to Object Oriented Tcl and particularly referencing
variable $w which points to the top level widget. The problem occurs when I
try to open a .psf file (see 2 last lines of code):

package provide tt_GUI 1.0

namespace eval ::tt_GUI:: {

  namespace export startGUI
   variable w

}

proc ::tt_GUI::startGUI {} {

   variable w

   # make the initial window
   set w [toplevel ".tt_GUI"]
   wm title $w "Truncate Trajcetory"
   wm resizable $w 0 1

   label $w.psfLab -text { Select trajcetory .psf file : }
   label $w.psfPathLab -text {No file selected}

   button $w.psfBut -command {set types {
           {".psf Files" {.psf} }
           }
           set file [tk_getOpenFile -filetypes $types -parent .]
           $w.psfPathLab configure -text $file} \
           -text Open

....(irrelevant code)....

}

The error message I get is:

can't read "w": no such variable can't read "w": no such variable

     while executing

"$w.psfPathLab configure -text $file"

     invoked from within

".tt_GUI.psfBut invoke"

     ("uplevel" body line 1)
     invoked from within

"uplevel #0 [ <http://wiki.tcl.tk/_edit/22154>list $w
invoke]<http://wiki.tcl.tk/_edit/22154>
"

     (procedure "tk::ButtonUp" line 22)
     invoked from within

"tk::ButtonUp .tt_GUI.psfBut "

     (command bound to event)

That should be a piece of cake for a Tcl programmer but unfortunately I'm
not that familiar with OO Tcl. I would deeply appreciate any help.

Tom

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