use 5.010;
use strict;
use warnings;

sub callback_host(&) {
  my ($thunk) = @_;
  say "In callback host, knowing nothing about blafus";
  $thunk->();
}

sub callback($) {
  my ($blafu) = @_;
  say "In callback, got the blafu '$blafu'";
}

my @blafus = qw/hallo ich peter/;

for my $blafu (@blafus) {
  say "In loop, current blafu '$blafu'";
  callback_host {
    callback($blafu)
  }
}