#!/usr/bin/perl

use strict;
use List::Util qw(max);
use POSIX qw(ceil);
use Tk;

my $mw = new MainWindow();

my @fields = ("Name", "Street", "Postal code", "City");

my @l;
for (@fields) {
    my $f = $mw->Frame->pack(-fill => "x");
    my $l = $f->Label(-text => $_, -anchor => "w")->pack(-side => "left");
    push @l, $l;
    my $e = $f->Entry->pack;
}

my $maxwidth = max map { $_->reqwidth } @l;
my $fontwidth0 = $mw->fontMeasure($l[0]->cget("-font"), "0");
my $maxwidth_chars = ceil($maxwidth / $fontwidth0);

for (@l) {
    $_->configure(-width => $maxwidth_chars);
}
MainLoop;