#! /usr/local/bin/perl -w
   
   require 5.005;
   
   use strict;
   use English;
   
   use Tk;
   
   # Create main window with button and text widget in it...
   my $top = MainWindow->new;
   my $btn = $top->Button(-text=>'print odd lines')->pack;
   my $txt = $top->Scrolled('Text', -relief=>'sunken', -borderwidth=>'2',
	-setgrid=>'true', -height=>'30', -scrollbars=>'e');
   $txt->pack(-expand=>'yes', -fill=>'both');
   $btn->configure(-command=>sub{&GetText($txt)} );
   
   # Populate text widget with lines tagged odd and even...
   my $lno;
   my $oddeven;
   foreach $lno (1..20) {
	if($lno % 2) { $oddeven = "odd" } else { $oddeven = "even" };
	$lno = "Line $lno ($oddeven)\n";
	$txt->insert ('end', $lno, $oddeven);
   }
   
   # Do the main processing loop...
   MainLoop();
   
   sub GetText {
	my $txtobj = shift;

	$txtobj->tag('configure', 'odd', -background=>'lightblue');
	$txtobj->tag('configure', 'even', -background=>'lightgreen');

	# This is the goal of all the work...
	my @lines = $txtobj->get($txtobj->tagRanges('odd'));

	print STDERR join("", @lines);
   }