Nobody else has mentioned this, so I will

Private subroutines

In Pascal (sorry!) you can declare a sub within another sub. In Perl you can't. But you can define & use private subrefs:

sub my_realy_complicated_thing {
  my $easy_thing   = sub { ... };
  my $easier_thing = sub { ... };
  ...
  my $x = $easy_thing->( @lots_of_complicated_stuff );
  #etc
}
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Footnote
As I was typing this, I ended a sentence with ";"
Am I doing too much Perl?