Select Code to Download

perl -E '
    use Scalar::Util "looks_like_number";
...
-Inf: 1
Infinity: 1
-Infinity: 1

perl -E '
    use Scalar::Util "looks_like_number";
...
0b10: 0
0o10: 0
0x10: 0

perl -E '
    use Scalar::Util "looks_like_number";
...
2: 1
8: 1
16: 1

sub IsNumber {
    state $re = qr{...};
    return $_[0] =~ $re;
}

{
    my $re; BEGIN { $re = qr{...} }
...
        return $_[0] =~ $re;
    }
}

$ perl -E 'say 1e6'
1000000

$ perl -E 'say 1_000_000/1_000'
1000