sub extract {
    my %args = @_;

    my @arr = @{$args{arr}};         
    my ($bf, $bt) = @{$args{range}};   
    if ($bf > $bt) {
        ($bf, $bt) = ($bt, $bf); 
        @arr = reverse @arr;       
    }
    die "Out of range" unless @arr == $bt - $bf + 1;
    my ($from, $to) = @{$args{subrange}}; 
    my @range = $from <= $to ? $from..$to : reverse($to..$from);

    die "Out of range" if $range[0] < $bf || $range[0] > $bt ||
         $range[-1] < $bf || $range[-1] > $bt;

    local $" = ", ";
    my @a = eval "local \$[ = $bf; \@arr[@range]";
    die $@ if $@;
    \@a;
}



my $a = extract arr      => [qw /cero uno dos tres/],
                range    => [5, 8],
                subrange => [6, 5];

print "$_\n" for @$a;
__END__
uno
cero
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