Zen Cart Big Spender adds discounting by subtotal with filtering

One of my customers want to discount by dollars spent but NOT discount any product on sale, and also not discount specific products selectable by category, product id or manufacturer.  So I added set_cart_discount_products() to Big Spender 1.2.17, which starts from the product  subtotal and then allows you to filter out specific products (using the filters indicated above) with the cart_filter_product() function.

Here’s an example configuration, in the setup() function

 $this->add_threshold(500, 'Spend over $500, get 30% off', false);
 $this->set_cart_discount_products("%",30);
 $this->set_deal_id(500);

 $this->add_threshold(250, 'Spend over $250, get 25% off', false);
 $this->set_cart_discount_products("%",25);
 $this->set_deal_id(250);
 $this->set_no_double_dip_list(500);

 $this->add_threshold(100, 'Spend over $100, get 20% off', false);
 $this->set_cart_discount_products("%",20);
 $this->set_deal_id(100);
 $this->set_no_double_dip_list(500,250);

 $this->add_threshold(50, 'Spend over $50, get 20% off', false);
 $this->set_cart_discount_products("%",20);
 $this->set_deal_id(50);
 $this->set_no_double_dip_list(500,250,100);