use strict;
use warnings;

use Data::Dumper;

my %properties;
while (my $propline = <DATA>) {
   next if $propline =~ /^#/;
   chomp $propline;
   my ($key, $value) = split(/=/, $propline, 2);
   _insert(\%properties, $key, $value);
}

sub _insert {
	my ($root, $key, $value) = @_;
	my ($first, $rest) = split /\./, $key, 2;
	if (defined $rest) {
		$root->{$first} = {} unless ref($root->{$first}) eq 'HASH';
		_insert($root->{$first}, $rest, $value);
	} else {
		$root->{$first} = $value;
	}
}

print Dumper(\%properties);

__DATA__