The Bowling Score Kata in (mainly) Functional Kotlin
I don’t often have a title in mind when I record these videos - I just write code and then look for an emerging theme while I’m editing - preferably one that will interest you enough to click through and watch until the end.
Having completed this, the 4th part of our 10 pin bowling simulator, I’m still not sure what the theme is. You should totally watch it though, and then let me know what you learned in the comments.
In this episode
00:00:37 I've made the tests easier to read
00:01:18 Start modifying our tests to include the score
00:01:38 I think that we got our domain model wrong with the Score being part of Frame
00:02:41 Make some space for new code
00:03:12 Mutating a var in a map! Horror!
00:03:45 Split rendering the score from rendering the frame
00:05:38 Now we can use our types
00:06:57 Discovering new operations on our existing types
00:09:42 Implement totalPinCount as a method
00:11:04 Re-enable tests now they have a hope of passing
00:13:46 Now raise the bar with strikes
00:14:32 Always strive to keep tests as simple as possible
00:16:50 Now spares
00:18:48 Scoring makes us re-evaluate our basic model again
00:21:28 Sometimes we get lucky and tests break
00:22:22 Commit
00:22:33 Wrap up
You can see the code on GitHub https://github.com/dmcg/bowling-for-y... and this miniseries in a playlist • Bowling Kata
If you like this, you’ll probably like my book Java to Kotlin, A Refactoring Guidebook (http://java-to-kotlin.dev). It's about far more than just the syntax differences between the languages - it shows how to upgrade your thinking to a more functional style.
