use constant {
    TYPE      => 0,
    ACTION    => 1,
    EXCEPTION => 2,
};

my @tasks = (
  #  TYPE     ACTION            EXCEPTION
  [ 'system', "foo --bar baz",  "foo failed." ],
  [ 'chdir',  'foobar',         "Couldn't chdir to foobar." ],
  [ 'system', "foo --bar baz2", "Couldn't pull it off." ],
  [ 'system', "foo2 --bar baz", "No joy. foo2 had problems." ],
  [ 'chdir',  '..',             "Couldn't go back up to base dir." ],
  [ 'system', "bar --foo baz",  "Darn. bar didn't make it." ],
);

%TASK_DISPATCHER = (
    system => sub {
        system( $_[ACTION] ) == 0 
            or die "$_[EXCEPTION]\n";
    },
    chdir => sub {
        chdir $_[ACTION] 
            or die "$_[EXCEPTION] $!\n";
    },
    '' => sub {
        die "Illegal task type '$_[TYPE]' specified\n";
    }
);

foreach my $task ( @tasks ) {
    
    my $type = exists $TASK_DISPATCHER{$task->[TYPE]} 
               ? $task->[TYPE] 
               : '';

    $TASK_DISPATCHER{$type}->( @$task );

}