RT125758

gistfile1.txt

# Linux
> perl6 rt125758.pl6
# STARTED
2
1
3
# FINISHED

gistfile2.txt

# OSX
> perl6 rt125758.pl6
# STARTED
2
# FINISHED

rt125758.pl6

class Processor {
    has @.processes; # [[cmd1, cmd2], [cmd3]]
    has $.process-a1;
    has $.process-a2;
    has $.process-b1;

    submethod BUILD {
        my $id = 0;
        $!process-a1 := Proc::Async.new('echo', ++$id);
        $!process-a2 := Proc::Async.new('echo', ++$id);
        $!process-b1 := Proc::Async.new('echo', ++$id);

        @!processes.push([$!process-a1, $!process-a2]);
        @!processes.push([$!process-b1]);
    }

    method start-processes {
        my $p = Promise.new;
        $p.keep(1);

        for @!processes -> $group {
            $p = $p.then: {
                my @promises := $group>>.start;
                await Promise.allof(@promises) if @promises;
                sleep 5;
            }
        }

        $p;
    }
}

my $processor = Processor.new;

say "# STARTED";
await $processor.start-processes;
say "# FINISHED";