Without seeing the rest of your code and not really sure what value the widget ( $t->index('insert') ) is actually returning, you said '2.0'... Since I am not sure what widget you are using... I would maybe try qq/ $t->index('insert')/ or $t->index('insert').""... since perl may be trying to cast the index into a number instead of leaving it as a string The following works for me on AS 5.8.3 build 809 and Tk 804.021: 
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);

}

[download]

JamesNC

In reply to Re: Valid values of Tk::Text see() function. by JamesNC
in thread Valid values of Tk::Text see() function. by Anonymous Monk

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