![Util class Collections2.transform(
Collections2.filter(
list,
(foo) -> foo.isValid()),
(foo) -> new Bar(foo)));
No Util Class scala.collection.Iterable[T]
declares 116 methods](https://image.slidesharecdn.com/tradeoffs-130614141930-phpapp02/75/Language-Design-Trade-offs-28-2048.jpg)
![Java static char last(String s)
Usage “abc”.last()
C# static char last(string this)
Kotlin fun String.last(): Char {
return this[this.size - 1]
}](https://image.slidesharecdn.com/tradeoffs-130614141930-phpapp02/75/Language-Design-Trade-offs-31-2048.jpg)
![Java new List<String>()
Collections.<String>emptyList()
Why different?
Scala new List[String]()
emptyList[String]()
arr(0)
Why square brackets?](https://image.slidesharecdn.com/tradeoffs-130614141930-phpapp02/75/Language-Design-Trade-offs-35-2048.jpg)
Uploaded byAndrey Breslav
Language Design Trade-offs
The document discusses language design trade-offs in programming, focusing on aspects such as elegance, convenience, and complexity. It compares Java, Kotlin, and Scala in terms of their collections and error handling capabilities, highlighting differences in syntax and functionality. It emphasizes the importance of safe, compatible, and intuitive code while addressing developer experience over theoretical ideals.
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Language Design Trade-offs
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- 9. Clever Readable Simple Fast ShinyNew Good Old Ground-Breaking Compatible
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- 11. As Java Evolved… Foo<?extends T> new Foo() new Foo<T>() new Foo<>() SAM-Conversions Default methods
- 12. Lambdas & SAM-Conversions voidfoo(Function<? super Bar, ? extends Baz> g) SAM-type foo(g -> new SubBaz(g));
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- 15. Boxing for Primitives newFoo() The Age of (Auto)Boxing
- 16. Language Runtime JIT x86 amd64 ARM GC x86amd64 ARM Threads Linux Windows Mac Hard Very Hard
- 17.
- 18. JDK Collections interfaceList<E> { E get(int index); E set(int index, E value); } Read-only /** read-only */ List<Foo> getFoos() { return unmodifiableList(l); } Errors At Runtime
- 19. Cool Collections interfaceList<E> { E get(int index); } interface MutableList<E> extends List<E> { E set(int index, E value); } Read-only List<Foo> getFoos() { return l; // may be mutable } Errors At Compile Time
- 20. Safe Compatible Cool CollectionsJDK Collections catch errors early self-documenting code no wrapping/repackaging existing API’s work Intuitive ? extends Foo print(List<? extends Foo> foos)print(foos: List<Foo>)
- 21. Iterable<out T> Collection<out T> List<outT> Set<out T> MutableIterable<T> MutableCollection<T> MutableList<T> MutableSet<T> java.lang.ArrayList<T> java.util.HashSet<T> Kotlin Collections JDK Collections
- 22. Kotlin Collections =& Safe Compatible Co-variant
- 23. Java String s= null; s.length(); Errors At Runtime Kotlin val s: String s.length() val s: String? = null s.length() Errors At Compile Time = null Nullable type
- 24. Check and useval s: String? = … if (s != null) { s.length() } Check and exit if (s == null) return s.length() Rock’n’Roll s?.length()
- 25. JAR File class Foo{ String getName() { … } } Nullable or Not? <XML/> @NotNull KAnnotator
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- 28. Util class Collections2.transform( Collections2.filter( list, (foo)-> foo.isValid()), (foo) -> new Bar(foo))); No Util Class scala.collection.Iterable[T] declares 116 methods
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- 31. Java static charlast(String s) Usage “abc”.last() C# static char last(string this) Kotlin fun String.last(): Char { return this[this.size - 1] }
- 32. Access privates No VirtualNo Owner Package Many Applicable Overloading error Member Clashes Member wins = static utility
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- 35. Java new List<String>() Collections.<String>emptyList() Whydifferent? Scala new List[String]() emptyList[String]() arr(0) Why square brackets?
- 36. foo(bar<A, B>(x +1)) foo(bar < a, b > (x + 1))
- 37. Java Familiar (fromC++) Sometimes ugly Scala Always pretty Unfamiliar C# and Kotlin Familiar Always* pretty emptyList<String>() * foo((bar < A), B > (x+1))
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