The Case for Kotlin and Ceylon

My DevoxxUK 2017 presentation introducing Kotlin and Ceylon to a Java audience

Transcript

1. Copyright © 2017 Russel Winder 1 The Case for Kotlin and Ceylon Russel Winder @russel_winder russel@winder.org.uk https://www.russel.org.uk
2. Copyright © 2017 Russel Winder 2 Java is stagnant, thankfully we have Kotlin and Ceylon Russel Winder @russel_winder russel@winder.org.uk https://www.russel.org.uk
3. Copyright © 2017 Russel Winder 3 The Case for Kotlin and Ceylon Russel Winder @russel_winder russel@winder.org.uk https://www.russel.org.uk
4. Copyright © 2017 Russel Winder 4 The “Prosecution” Advocate • Ex theoretical physicist • Ex UNIX systems programmer • Ex academic: – Parallel programming – Software development and programming – HCI, UI, UX • Ex Company director • Ex Independent consultant • Ex analyst • Ex author • Ex expert witness • Ex trainer Russel Winder
5. Copyright © 2017 Russel Winder 5 The “Defence” Advocate Appears to be missing. :-) The audience will have to substitute.
6. Copyright © 2017 Russel Winder 6 The Jury That’s you the audience.
7. Copyright © 2017 Russel Winder 7 Prologue
8. Copyright © 2017 Russel Winder 8 An outline case presented, much, much more detail is available.
9. Copyright © 2017 Russel Winder 9 Introduction
10. Copyright © 2017 Russel Winder 10 Java is… • …an “old” programming language steeped in “imperative” and “object oriented” history. • …a programming language, evolving very slowly. • …not really keeping up with modern programming ideas and techniques.
11. Copyright © 2017 Russel Winder 11 The Java Platform is… • …a mature and extensive hardware-independent platform. • …evolving very, very slowly. • …a platform for many programming languages: – Java, Scala, Kotlin, Ceylon, Frege, Groovy, Fantom, Gosu, … – Groovy, Clojure, JRuby, Jython, Golo, …
12. Copyright © 2017 Russel Winder 12 Some Philosophy
13. Copyright © 2017 Russel Winder 13 Is Change Good?
14. Copyright © 2017 Russel Winder 14 Is Change Good? • Change threatens backward compatibility, backward compatibility is determined to be sacrosanct, ergo no. • Change enables new knowledge, new techniques, new tools, ergo yes.
15. Copyright © 2017 Russel Winder 15 Assembly languages Procedural languages Functional languages Object-oriented languages ? Logic languages Machine code
16. Copyright © 2017 Russel Winder 16 Backward compatibility is the enemy of progress.
17. Copyright © 2017 Russel Winder 17 Backward compatibility is the excuse of the lazy to avoid work.
18. Copyright © 2017 Russel Winder 18 Backward compatibility is the way applications become outdated and broken.
19. Copyright © 2017 Russel Winder 19 Is backward compatibility the biggest threat to Java?
20. Copyright © 2017 Russel Winder 20 Moving On
21. Copyright © 2017 Russel Winder 21 Distinguish Java the language from JVM and Java Platform.
22. Copyright © 2017 Russel Winder 22 If Java will not change…
23. Copyright © 2017 Russel Winder 23 Assembly languages Procedural languages Functional languages Object-oriented languages ? Logic languages Machine code
24. Copyright © 2017 Russel Winder 24 Scala, touted as a replacement for Java, incorporates functional programming into an object oriented language. However…
25. Copyright © 2017 Russel Winder 25 Many took to Scala, but many found it unsatisfactory. Kotlin and Ceylon are two of the results.
26. Copyright © 2017 Russel Winder 26 The Two Languages • Kotlin – Interwork with Java allowing incremental change of codebase. – Influenced by Java, Groovy, Scala. – Superior type system to Java. • Ceylon – Replace Java but use the Java Platform. – Module based from the outset. – Far superior type system to Java.
27. Copyright © 2017 Russel Winder 27 Both Kotlin and Ceylon Can compile to JVM or JavaScript.
28. Copyright © 2017 Russel Winder 28 Both Kotlin and Ceylon are languages of the 2010s.
29. Copyright © 2017 Russel Winder 29 Hello World has to be done
30. Copyright © 2017 Russel Winder 30 /** * The Hello World program in Kotlin. * * @author Russel Winder */ fun main(args:Array<String>) { println("Hello World.") } "The Hello World program in Ceylon." by("Russel Winder") shared void run() { print("Hello World."); } Top level functions. /** * The Hello World program in Java * * @author Russel Winder */ public class HelloWorld_Java { public static void main(final String[] args) { System.out.println("Hello World."); } }
31. Copyright © 2017 Russel Winder 31 Doing everything with classes and packages as in Java (and Scala) seen as too restrictive. Adding top level functions, etc. seen as right, make the compiler do the work of creating classes for the JVM.
32. Copyright © 2017 Russel Winder 32 Factorial is required
33. Copyright © 2017 Russel Winder 33 Code
34. Copyright © 2017 Russel Winder 34 Let’s look at anagrams Or word count
35. Copyright © 2017 Russel Winder 35 Code
36. Copyright © 2017 Russel Winder 36 Some Further Thoughts
37. Copyright © 2017 Russel Winder 37 Operator overloading was deemed too hard for programmers to cope with by the inventors of Java. Most JVM languages since have put it back, one way or another.
38. Copyright © 2017 Russel Winder 38 Language evolution by replacement.
39. Copyright © 2017 Russel Winder 39 Kotlin and Ceylon represent two possible futures on the JVM.
40. Copyright © 2017 Russel Winder 40 Headlines • Kotlin: – More declarative than Java. – Less code. – Mixed language codebase. – More expressive than Java. • Ceylon: – More declarative than Java. – Modules. – Far better type system than Java. – More expressive than Java.
41. Copyright © 2017 Russel Winder 41 Both Kotlin and Ceylon run on Android.
42. Copyright © 2017 Russel Winder 42 A Challenge to You Try all this in Java.
43. Copyright © 2017 Russel Winder 43 The Case for Kotlin and Ceylon Russel Winder @russel_winder russel@winder.org.uk https://www.russel.org.uk