Question

I have the following code in my class :

 sub new {     my $class = shift;     my %args  = @_;     my $self  = {};     bless( $self, $class );     if ( exists $args{callback} ) {         $self->{callback} = $args{callback};     }     if ( exists $args{dir} ) {         $self->{dir} = $args{dir};     }     return $self; }  sub test {   my $self = shift;   my $arg  = shift;   &$self->{callback}($arg); }  

and a script containing the following code :

 use strict; use warnings; use MyPackage;  my $callback = sub {    my $arg = shift;    print $arg; };  my $obj = MyPackage->new(callback => $callback);  

but I receive the following error:

Not a CODE reference ... 

What am I missing? Printing ref($self->{callback}) shows CODE. It works if I use $self->{callback}->($arg), but I would like to use another way of invoking the code ref.

Answer 1

The ampersand is binding just to $self and not the whole thing. You can do curlies around the part that returns the reference:

&{$self->{callback}}($arg); 

But the

$self->{callback}->($arg); 

is generally considered cleaner, why don’t you want to use it?