Can anybody please explain (my $self = shift) in Perl

Question

I\'m having a really hard time understanding the intersection of OO Perl and my $self = shift; The documentation on these individual elements is great, but none of

Answer 1

In top level-code, shift() is short for shift(@ARGV). @ARGV contains the command-line arguments.

In a sub, shift() is short for shift(@_). @_ contains the sub's arguments.

So my $self = shift; is grabbing the sub's first argument. When calling a method, the invocant (what's left of the ->) is passed as the first parameter. In other words,

$o->method(@a)

is similar to

my $sub = $o->can('method');
$sub->($o, @a);

In that example, my $self = shift; will assign $o to $self.