Another little value dialog

This is a inputbox to enter a textstring, e.g. like tk_messageBox with buttons "OK", "Cancel" and an entry-field.

 proc tk_getString {w var title text} {
    variable ::tk::Priv
    upvar $var result
    catch {destroy $w}
    set focus [focus]
    set grab [grab current .]

    toplevel $w -bd 1 -relief raised -class TkSDialog
    wm title $w $title
    wm iconname  $w $title
    wm protocol  $w WM_DELETE_WINDOW {set ::tk::Priv(button) 0}
    wm transient $w [winfo toplevel [winfo parent $w]]

    entry  $w.entry -width 20
    button $w.ok -bd 1 -width 5 -text Ok -default active -command {set ::tk::Priv(button) 1}
    button $w.cancel -bd 1 -text Cancel -command {set ::tk::Priv(button) 0}
    label  $w.label -text $text

    grid $w.label -columnspan 2 -sticky ew -padx 3 -pady 3
    grid $w.entry -columnspan 2 -sticky ew -padx 3 -pady 3
    grid $w.ok $w.cancel -padx 3 -pady 3
    grid rowconfigure $w 2 -weight 1
    grid columnconfigure $w {0 1} -uniform 1 -weight 1

    bind $w <Return>  {set ::tk::Priv(button) 1}
    bind $w <Destroy> {set ::tk::Priv(button) 0}
    bind $w <Escape>  {set ::tk::Priv(button) 0}

    wm withdraw $w
    update idletasks
    focus $w.entry
    set x [expr {[winfo screenwidth  $w]/2 - [winfo reqwidth  $w]/2 - [winfo vrootx $w]}]
    set y [expr {[winfo screenheight $w]/2 - [winfo reqheight $w]/2 - [winfo vrooty $w]}]
    wm geom $w +$x+$y
    wm deiconify $w
    grab $w

    tkwait variable ::tk::Priv(button)
    set result [$w.entry get]
    bind $w <Destroy> {}
    grab release $w
    destroy $w
    focus -force $focus
    if {$grab != ""} {grab $grab}
    update idletasks
    return $::tk::Priv(button)
 }

# Usage:

 if {[tk_getString .valueDlg value "Dialog" "Please enter some text"]} {
   #catch {console show}
   #puts "user entered: $value"
    pack [ label .l -text "User entered: '$value' " ]
 }

--AF 22-06-03

updated on 23-06-03 on de's suggestion to set transient and restore previous grab