use Tk;
use strict;
my $mw = tkinit;
$mw->geometry('100x100');

my $linenumbers = $mw->Text()->pack(-fill, 'both', -expand, 1);

&line_num(30);

MainLoop;

sub line_num {
   my $total_lines = shift;
   #my $line_number = qq($t->index('insert')); #?
   my $line_number = '21.0';
   print $line_number,"\n";

   $linenumbers->delete("0.1", "end");
   
   for (0..$total_lines) {
      $linenumbers->insert('end', join "\n", map {sprintf "%4d\n", $_ } $_);
   }
   #$linenumbers->yviewMoveto($line_number/$total_lines);
   #$linenumbers->yview(-pickplace, $line_number);
   $linenumbers->see($line_number);

}