In Perl, how can a subroutine get a coderef that points to itself?

Question

For learning purposes, I am toying around with the idea of building event-driven programs in Perl and noticed that it might be nice if a subroutine that was registered as an

Answer 1

To get a reference to the current subroutine without using an extra variable, you can use a tool from functional programming, the Y-combinator, which basically abstracts away the process of creating the closure. Here is a perlish version:

use Scalar::Util qw/weaken/;

sub Y (&) {
    my ($code, $self, $return) = shift;
    $return = $self = sub {$code->($self, @_)};
    weaken $self;  # prevent a circular reference that will leak memory
    $return;
}

schedule_event( Y { my $self = shift; ... }, 0);