Functional programming with Xtend
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The document discusses the principles of functional programming compared to imperative programming, emphasizing immutability and first-class functions. It highlights the benefits of immutability in Java coding, including thread safety and improved readability, along with practical examples like the creation of immutable data types. Additionally, the document introduces concepts such as lambdas and higher-order functions as part of functional programming.
Functional programming with Xtend
- 1. Functional Programming with Jan Köhnlein & Sven Efftinge
- 2. Functional programming is like describing your problem to a mathematician. Imperative programming is like giving instructions to an idiot.
- 3. Imperative vs Functional State Changes vs No State Change How? vs What?
- 5. #1 : No Side-Effects
- 6. Haskell is a purely-functional programming language
- 7. Most other functional programming languages are more relaxed, i.e. non-pure.
- 8. Most other functional programming languages are more relaxed, i.e. non-pure. But still embrace immutability!
- 9. Why Immutability? Thread-Safety Easy to test, construct and use Good Map keys and Set members Code is easier to read and understand
- 11. The beauty of java.lang.String Thread-Safety Easy to test, construct and use Good Map keys and Set members Code is easier to read and understand
- 12. "Classes should be immutable unless there's a very good reason to make them mutable...” (Joshua Bloch)
- 13. "When you create immutable classes, entire categories of problems simply disappear.” (javapractices.com)
- 14. How to build an immutable data type in Java? make everything final create constructor for fields implement hashcode implement equals
- 15. writing Immutable code in Java is tedious & error-prone
- 16. Immutability in final by default val vs. var immutable collection literals everything is an expression @Pure @Data
- 17. First Exercise Immutable Data Types
- 19. #2 : First-Class Functions
- 20. #2 : First-Class Functions passing functions as arguments higher-order functions lambdas
- 21. An Example
- 23. @Data class Movie { String title int year double rating long numberOfVotes ImmutableSet<String> categories }
- 24. What’s the best drama of the 70ies?
- 29. Java 8 Lambdas
- 30. Lambdas
- 32. Second Exercise In The Movies
- 33. Use the force, Duke! www.xtend-lang.org