#!/usr/bin/perl -w

use strict;

my $tasks = 
{

	"A_Task_2" =>
	{
		priority => 2,
 	},

	"A_Task_1" =>
	{
		priority => 1,
 	},

	"A_Task_3" =>
	{
		priority => 3,
 	},

	"B_Task_1" =>
	{
		priority => 1,
      task_depends =>
			[
				'A_Task_1',
				'A_Task_2',
				'A_Task_3',
				'A_Task_4',
			],
 	},

   "A_Task_4" =>
	{
		priority => 4,
 	},

};

# for my $taskname (sort keys %$tasks)   # works fine
for my $taskname (sort { $tasks->{priority} <=> $tasks->{priority} } keys %$tasks )   # not working - can you see what I'm trying to do?
{
   my $task = $tasks->{$taskname};
   print  $task->{priority} , "-", $taskname, "\n"  ;  # works 
   sleep(1) ;
}