Question

Perl usually converts numeric to string values and vice versa transparently. Yet there must be something which allows e.g. Data::Dumper to discriminate between both, as in this example:

use Data::Dumper;
print Dumper('1', 1);

# output:
$VAR1 = '1';
$VAR2 = 1;

Is there a Perl function which allows me to discriminate in a similar way whether a scalar’s value is stored as number or as string?

Answer 1

There’s no way to find this out using pure perl. Data::Dumper uses a C library to achieve it. If forced to use Perl it doesn’t discriminate strings from numbers if they look like decimal numbers.

use Data::Dumper;
$Data::Dumper::Useperl = 1;
print Dumper(['1',1])."\n";

#output
$VAR1 = [
          1,
          1
        ];