How do you use type constraints with a short example?

Type constraints in Perl provide a way to enforce certain conditions on the data types of variables or function parameters. You can use the Moose framework to define type constraints easily. Here's a short example demonstrating how to use type constraints with Moose:


        use Moose;
        use Moose::Util::TypeConstraints;

        subtype 'PositiveInt',
            as 'Int',
            where { $_ > 0 },
            message { "The value must be a positive integer." };

        has 'age' => (
            is       => 'rw',
            isa      => 'PositiveInt',
            required => 1,
        );

        my $person = Person->new(age => 25); # This is valid
        my $invalid_person = Person->new(age => -5); # This will throw an error