How to make a rule for limiting one product per cart Can anyone help me?
I want to know how to make a rule for limiting one product per cart. I found rule for limiting qty only but not order item.

I found this with code Drupal Commerce Shopping cart limit
But I want to do it with rule ...
Yes, to restrict to one product per order, add a rule:


Event: before add product to cart, 
Action: remove all products from cart.


The effect is existing products are removed and only the latest selected product is added to the cart.