hi, i am building a shopping cart and cant figure out how to store something like this into a session.

[product_id1] = quantity;
[product_id1] = size
[product_id1] = color;

[product_id2] = quantity;
[product_id2] = size;
[product_id2] = color;
...
etc

so when a user select the quantity of a product then selects its color then selects to add to a cart i want the items selected to be added into a session and each item added to the cart , its attributes selected to be added into a session. how would i do this?

many many thanks.