use Test::More tests => 1;

my @data     = qw( 000-      0101 011-      1-0- );
my @expected = qw( 0000 0001 0101 0110 0111 1000 1001 1100 1101 );

my @got = map { expand_binary( $_ ) } @data;
is_deeply \@got, \@expected;

sub expand_binary {
    my $bin = shift;
    if ( $bin =~ /-/ ) {
        ( my $zero = $bin ) =~ s/-/0/;
        ( my $one  = $bin ) =~ s/-/1/;
        return ( expand_binary( $zero ), expand_binary( $one ) );
    }
    return $bin;
}
[download]