Kotlin Programming: The Big Nerd Ranch Guide, First Edition

Extracting to Extensions

Next, you will apply what you have learned to refine NyetHack. Open the project and the Tavern.kt file.

Tavern.kt contains duplicate chains of logic called on several collections: shuffled().first().

    ...
    (0..9).forEach {
        val first = patronList.shuffled().first()
        val last = lastName.shuffled().first()
    }

    uniquePatrons.forEach {
        patronGold[it] = 6.0
    }

    var orderCount = 0
    while (orderCount <= 9) {
        placeOrder(uniquePatrons.shuffled().first(),
                menuList.shuffled().first())
        orderCount++
    ...

This duplication indicates an opportunity to extract the duplicate logic to a reusable extension.

Define a new extension called random at the top of Tavern.kt:

Listing 18.11  Adding a private random extension (Tavern.kt ...