gistfile1.prolog

use v6;

class Task {
   has &.callback;
   has Task @.dependencies;
   has Bool $.done;

   method new( &callback, *@dependencies ){
      self.bless(*, :&callback,  :@dependencies );
   }
   
   method add-dependency( Task $dependency ){
      push @!dependencies, $dependency;
   }

   method perform(){
      unless $!done {
         .perform() for @!dependencies;
         &!callback();
         $!done = True;
      }
   }
};

my $eat = Task.new( { say 'eating dinner1.'}  );
$eat.add-dependency( Task.new( { say 'making dinner' } ) );
#my $eat = Task.new( { say 'eating dinner. NOM!' },
#    Task.new( { say 'making dinner' },
#      Task.new( { say 'buying food' },
#        Task.new( { say 'making some money' } ),
#        Task.new( { say 'going to the store.' } )
#      ),
#      Task.new( { say 'cleaning kitchen' } )
#    )
#);

$eat.perform();

The Error I get is:
perl6 Task.pm
Nominal type check failed for parameter '@Dependencies'; expected Positional but got Array instead
in method new at Task.pm:8
in block at Task.pm:24

perl6 --version
This is perl6 version 2012.09.1 built on parrot 4.6.0 revision 0