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Gdg dev fest 2107 to kotlin, with love
Ayman Mahfouz, a VP of Engineering with 20 years in software development, shares insights on Kotlin, highlighting its features like brevity, null safety, conditionals, smart casts, and lambdas. He contrasts Kotlin's strengths with Java, emphasizing how Kotlin simplifies code with its expressive syntax and compile-time enforced null safety. The document serves as a brief introduction to Kotlin's advantages over other programming languages.
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Gdg dev fest 2107 to kotlin, with love
- 1. To Kotlin, withL ve Ayman Mahfouz
- 2. Biography (boooooring!) - VPof Engineering at Webalo - Los Angeles based - UX4IIoT - 20 years of software development - PhD. in software engineering
- 3. Programming Languages Pascal CC++ Java Python C# Objective-C ActionScript Scala Ruby Octave JavaScript Go TypeScript Kotlin BASIC
- 4. Kotlin Arrives! - Paidlittle attention until Google I/O announcement. - Android Studio Canary 3. - Immediately fell in love - Strongly-typed - Brief - Expressive - Interoperable with Java - Growing support - Starts from where others ended (Java, Python, Go, Swift)
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- 6. Brevity In Java, onewould normally write this: With my background, I translated this into Kotlin verbatim: Not idiomatic but still shorter! Can you spot the omissions? ● No ; ● No “new” ● “override” is a modifier ● “:” not “implements” ● “public” is default ● Return type In Java one would typically write code like this:
- 7. Brevity Using “Single ExpressionFunction” syntax Pass a lambda expression to a function that accepts a single-method interface
- 8. Brevity Omit parameter type Omitparameter name as well Eliminate left hand side completely Lambda expression only argument so we can eliminate the parenthesis Omit parameter type
- 9. Brevity to Kotlin ... FromJava ... With love!
- 10. We will gothrough: Brevity Null Safety Conditionals Smart Cast Lambdas Collections
- 11. Null Safety The dreadedNPE Handle explicitly
- 12. Null Safety Handle viaJava 8 Optionals - very verbose! Handle by convention: - Special member naming (IfAny) - Null checks in constructor - Hand-coded - AspectsOr let it throw! (pun intended)
- 13. Null Safety Kotlin safenavigation operator Compile-time language-enforced null safety Forced init Force null guard Allowing late init Conscious NPE
- 14. We will gothrough: Brevity Null Safety Conditionals Smart Cast Lambdas Collections
- 15. Conditionals I cringe whenI see if statements that look like this Use the ternary operator please!
- 16. Conditionals In Kotlin, ifstatement is an expression Combined with single expression function shorthand So you can write a function like this
- 17. Conditionals I hate “Switch”statements! But I love “when” expressions! 1. No annoying “break” or even “case” 2. Match against any type 3. Switch variable can be of any type
- 18. We will gothrough: Brevity Null Safety Conditionals Smart Cast Lambdas Collections
- 19. Smart Cast In Javaexplicit cast is needed In Kotlin Smart Cast takes place automatically
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- 22. Smart Cast Automatic castto non-null
- 23. We will gothrough: Brevity Null Safety Conditionals Smart Cast Lambdas Collections
- 24. Lambdas Think of itas a “function literal” The function “Array” produces an array by applying a lambda
- 25. Lambdas Higher-order functions: functionsthat take other functions as arguments
- 26. Lambdas Closures: lambdas canaccess variables in their outer scope
- 27. We will gothrough: Brevity Null Safety Conditionals Smart Cast Lambdas Collections
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- 29. Collections - Streaming Chaininglambda operations
- 30. Collections - Immutability InJava both mutable and immutable collections implement the same interface - Runtime error Kotlin uses different interfaces - Compile error
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