Find your way

#!ek9
defines module lesson.finding.shop

  defines class

    Total
      total as Integer: 0

      addItem()
        -> price as Integer
        //total grows by one item's price
        total += price

      subtotal() as pure
        <- rtn as Integer: total

      default operator ?

  defines function

    priceLabel() as pure
      -> price as Integer
      <- rtn as String: `Total: ${price}`

    doubled() as pure
      -> price as Integer
      <- rtn as Integer: price * 2

  defines program

    ShowTotal()
      stdout <- Stdout()
      total <- Total()
      total.addItem(5)
      total.addItem(10)
      stdout.println(priceLabel(total.subtotal()))
      stdout.println("The running total is shown above")

//EOF

#!ek9
defines module lesson.finding.shop

  defines function

    receiptFooter() as pure
      -> grandTotal as Integer
      <- rtn as String: `Grand total: ${grandTotal}`

  defines program

    ShowReceipt()
      stdout <- Stdout()
      total <- Total()
      total.addItem(20)
      stdout.println(receiptFooter(total.subtotal()))

//EOF

#!ek9
defines module lesson.finding.till

  defines program

    ShowTill()
      stdout <- Stdout()
      total <- 0
      total += 15
      stdout.println(`Till total: ${total}`)

//EOF