If it is simply the total number, extended according to quantity, then you can use the [nitems] tag. If you need this number for use in an embedded Perl script, you can use
$number = $Tag->nitems();
If it is the number of line items you need, then you can use a Perl script:
[perl]
return scalar @{$Carts->{main}};
[/perl]
(The 'main' refers to the main shopping cart.)
If you have SeparateItems in effect, and need the number of unique items, you could use:
[perl]
my $cart = $Carts->{main};
foreach my $item (@$cart) {
@items = split /\|/, $items;
$count = 0;
for (@items) {
$count++ unless $seen{$_}++;
}
$count;
[/perl]