Question

I am defining a method with an optional argument. Typically I would use something like this:

sub foo {
    ($self, $optarg) = @_;
    $optarg ||= 1;
}

I would like the optional argument to be treated as boolean, with the default being true. This obviously won’t work with the above, since $optarg will evaluate to false if the argument is not passed in.

Is there a way to differentiate the absence of an argument being passed and a value that evaluates to false?

Answer 1

This scales well to multiple optional arguments:

my $self = shift;
my $optarg = @_ ? shift : 1;

So does this, but it handles multiple required arguments better. Unfortunately, it violates the least-redundancy-possible principle.

my ($self, $optarg) = @_;
$optarg = 1 if @_ < 2;