Question

I understand one uses the ‘bless’ keyword in Perl inside a class’s ‘new’ method:

sub new {     my $self = bless { };     return $self; }     

But what exactly is ‘bless’ doing to that hash reference ?

Answer 1

In general, bless associates an object with a class.

package MyClass; my $object = { }; bless $object, 'MyClass'; 

Now when you invoke a method on $object, Perl know which package to search for the method.

If the second argument is omitted, as in your example, the current package/class is used.

For the sake of clarity, your example might be written as follows:

sub new {    my $class = shift;    my $self = { };    bless $self, $class;  }  

EDIT: See kixx‘s good answer for a little more detail.