Exercise 36: Ordering groceries

Support 100 food items added to the grocery list via "We need more {food_item}" or "Add {food_item} to the grocery list".

Add a "display the grocery list" command. This should display a full-screen white form with the header "Grocery List" at the top and with the list in a scrollable container. A command "Close that" should hide this form.

Add a "print the grocery list" command.

The command "Order the groceries for delivery at {time}" should place an order via the web. Once the user speaks this command, the computer should reply with "Speak the confirmation code to continue". The confirmation code should consist of the word "delta" followed by the number that represents the current day of week. So for Tuesday, the confirmation code is "delta two". Alternatively, the command "cancel that" can be used to abort. Techniques used from exercise 35 should be employed to implement a system that detects unexpected results and aborts operations. A successful order should be communicated as "Your grocery order was placed successfully. The total came to 85 dollars and 21 cents.".