NAME

    Parallel::Pipes - parallel processing using pipe(2) for communication
    and synchronization

SYNOPSIS

      use Parallel::Pipes;
    
      my $pipes = Parallel::Pipes->new(5, sub {
        # this is a worker code
        my $task = shift;
        my $result = do_work($task);
        return $result;
      });
    
      my $queue = Your::TaskQueue->new;
      # wrap Your::TaskQueue->get
      my $get; $get = sub {
        my $queue = shift;
        if (my @task = $queue->get) {
          return @task;
        }
        if (my @written = $pipes->is_written) {
          my @ready = $pipes->is_ready(@written);
          $queue->register($_->read) for @ready;
          return $queue->$get;
        } else {
          return;
        }
      };
    
      while (my @task = $queue->$get) {
        my @ready = $pipes->is_ready;
        $queue->register($_->read) for grep $_->is_written, @ready;
        my $min = List::Util::min($#task, $#ready);
        for my $i (0..$min) {
          # write tasks to pipes which are ready
          $ready[$i]->write($task[$i]);
        }
      }
    
      $pipes->close;

DESCRIPTION

    THIS IS EXPERIMENTAL.

    Parallel processing is essential, but it is also difficult:

    How can we synchronize our workers?

      More precisely, how to detect our workers are ready or finished.

    How can we communicate with our workers?

      More precisely, how to collect results of tasks.

    Parallel::Pipes tries to solve these problems with pipe(2) and
    select(2).

    App::cpm, a fast CPAN module installer, uses Parallel::Pipes. Please
    look at App::cpm
    <https://github.com/skaji/cpm/blob/master/lib/App/cpm.pm> or eg
    directory <https://github.com/skaji/Parallel-Pipes/tree/master/eg> for
    real world usages.

METHOD

 new

      my $pipes = Parallel::Pipes->new($number, $code);

    The constructor, which takes

    number

      The number of workers.

    code

      Worker's code.

 is_ready

      my @ready = $pipes->is_ready;
      my @ready = $pipes->is_ready(@pipes);

    Get pipes which are ready to write.

 is_written

      my @written = $pipes->is_written;

    Get pipes which are written.

 close

      $pipes->close;

    Close pipes (also shutdown workers).

AUTHOR

    Shoichi Kaji <skaji@cpan.org>

COPYRIGHT AND LICENSE

    Copyright 2016 Shoichi Kaji <skaji@cpan.org>

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

