use strict;
use warnings;

use Test::More;

my @zero = (0, 0.0, -0, -0.0, 0E0);
my @notzero = (1, -1, 1.1, -1.1, '', undef, 'foo', 'a string', 3, 4, \@zero);

plan tests => @zero + @notzero;

for my $scalar (@zero) {
    ok is_zero ($scalar), "$scalar is zero";
}

for my $scalar (@notzero) {
    ok !is_zero ($scalar), ($scalar // 'undef') . ' is not zero';
}

sub is_zero {
    my $scalar = shift;
    return defined ($scalar) && length ($scalar) && (!$scalar || $scalar eq '0E0');
}