References :: creating

References can be created in several ways:

1. By using the backslash operator on a variable, subroutine, or value. (This works much like the & (address-of) operator in C.) This typically creates another reference to a variable, because there's already a reference to the variable in the symbol table. But the symbol table reference might go away, and you'll still have the reference that the backslash returned. Here are some examples:

            $scalarref = \$foo;
            $arrayref  = \@ARGV;
            $hashref   = \%ENV;
            $coderef   = \&handler;
   

2. A reference to an anonymous array can be created using square brackets:

            $arrayref = [
                          'Laurel',
                          'Hardy',
                          ['Gummo', 'Zeppo', 'Chico']
                        ];
   

   The array has no name; it can only be accessed via its reference, $arrayref. Hence the reason it's called "anonymous."

3. A reference to an anonymous hash can be created using curly braces:

            $hashref = {
                         'AC1'  => q[Asheron's Call],
                         'ACDM' => q[Asheron's Call],
                         'AC2'  => q[Asheron's Call 2],
                       };
   

   As with the array in the preceding example, the hash has no name; it can only be accessed via its reference, $hashref.

4. A reference to an anonymous subroutine can be created using sub without a subroutine name:

            $coderef = sub { print "Who is Mattie Young?\n" }; 
   

   This subroutine can be called only via its reference, $coderef:

    1        # call anonymous subroutine via its reference
    2        &$coderef($arg);
    3