use Tkx;
use strict;

our (@data, @editctls, @buttons);

open IN, "test.txt";
flock IN, 1;
@data = <IN>;
close IN;

chomp @data;


our $mw = Tkx::widget->new(".");

for (my $x = 0; $x < @data; $x++) {
    push @editctls, $mw->new_ttk__entry(-width => 30, -textvariable => \$data[$x]);
    $editctls[$x]->g_grid(-row => $x, -column => 0);
    
    push @buttons, $mw->new_ttk__button(-text => "Update", -command => sub { update($x); } );
    $buttons[$x]->g_grid(-row => $x, -column => 1);
}

Tkx::MainLoop();    


sub update {

    my $which = shift;

    open DATA, "+<test.txt";
    my @stuff = <DATA>;
    $stuff[$which] = $data[$which] . "\n";
    seek DATA, 0, 0;
    print DATA @stuff;
    truncate DATA, tell(DATA);
    close DATA;
}