The Perl Toolchain Summit needs more sponsors. If your company depends on Perl, please support this very important event.
#!/usr/bin/perl

# the classical producer/consumer example, using semaphores
# one process produces items, sends a signal.
# another process waits for that signal and
# consumed the item.

use Coro;
use Coro::Semaphore;

my $produced = new Coro::Semaphore 0;
my $finished = new Coro::Semaphore 0;

async {
   for my $i (0..9) {
      print "produced $i\n";
      push @buffer, $i;
      $produced->up;
      cede if @buffer > 5; # simulate memory pressure ;)
   }
   print "work done\n";
   $finished->up;
};

async {
   while () {
      $produced->down;
      my $i = shift @buffer;
      print "consumed $i\n";
   }
};

$finished->down;

print "job finished\n";