Csharp7_Talk

Transcript

1. 1 What's new in C# 7.0? Mark Allibone @mallibone
2. 3 3 Mark Allibone, Head of Mobile @mallibone Noser Engineering AG Ambassador https://mallibone.com
3. 4 C# Entwicklung Managed Code Generics Language Integrated Query Dynamic + (Language Parity) C# 5.0 + VB 11.0 Windows 8 Runtime + Asynchrony C# 1.0 + VB 7.0 C# 2.0 + VB 8.0 C# 3.0 + VB 9.0 C# 4.0 + VB 10.0 The Age of Roslyn C# 6.0 + VB 12.0
4. 5 5 Roslyn
5. 6 C# 6 • Initialisierung von Auto Properties • Auto Properties ohne Setter • Expression Bodies • Verwendung statischer Klassen • «Null-conditional» Operator • String Interpolation • nameof • Intializer für Collections mit Indexzugriff • Exception Filter • await in catch- und finally-Blöcken
6. 7 C# 6 • Initialisierung von Auto Properties • Auto Properties ohne Setter • Expression Bodies • Verwendung statischer Klassen • «Null-conditional» Operator • String Interpolation • nameof • Intializer für Collections mit Indexzugriff • Exception Filter • await in catch- und finally-Blöcken
7. 8 C# Entwicklung Managed Code Generics Language Integrated Query Dynamic + (Language Parity) C# 5.0 + VB 11.0 Windows 8 Runtime + Asynchrony C# 1.0 + VB 7.0 C# 2.0 + VB 8.0 C# 3.0 + VB 9.0 C# 4.0 + VB 10.0 The Age of Roslyn C# 6.0 + VB 12.0 C# 7
8. 9 C# 7 8 new Features
10. 11 1. Numeric Literals // binary types public const int One = 0b0001; public const int Two = 0b0010; // grouping of numbers public const int Sixteen = 0b0001_0000; public const uint HexNumber = 0xFFFF_0000; public long Billion = 1_000_000_000_000L; public const double AvogadroConstant = 6.022_140_857_747_474e23;
12. 13 2. Tuples var oldStyle = new Tuple<string, string>("a", "b"); • Install NuGet package System.ValueType var letters = ("a", "b"); letters.Item1 = "firstLetter"; var firstLetters = (Alpha: "a", Beta: "b"); firstLetters.Alpha = "alpha" • Ohne var (string Alpha, string Beta) namedLetters = ("a", "b");
13. 14 Tuples als Returnwert private static (int Max, int Min) Range(IEnumerable<int> numbers) { int min = int.MaxValue; int max = int.MinValue; foreach (var n in numbers) { min = (n < min) ? n : min; max = (n > max) ? n : max; } return (max, min); }
14. 15 private static (int Max, int Min) Range(IEnumerable<int> numbers) { int min = int.MaxValue; int max = int.MinValue; foreach (var n in numbers) { min = (n < min) ? n : min; max = (n > max) ? n : max; } return (max, min); } Tuples als Returnwert
16. 17 17 Destructor
17. 18 3. Constructor => Destructor => Deconstructor public class Point { public double X { get; } public double Y { get; } public Point(double x, double y) { this.X = x; this.Y = y; } public void Deconstruct(out double x, out double y) { x = this.X; y = this.Y; } }
18. 19 Deconstructor: split into parts public class Point { public double X { get; } public double Y { get; } public void Deconstruct(out double x, out double y) { x = this.X; y = this.Y; } } // Deconstruction var p = new Point(3.14, 2.71); (double X, double Y) = p; Console.WriteLine($"(x,y): ({X},{Y})");
20. 21 21 out variables
21. 22 int result; // the old style if (int.TryParse(input, out result)) { Console.WriteLine(result); } else { Console.WriteLine("Could not parse input"); } 4. Declaration of out Variables
22. 23 4. Deklaration of out Variables if (int.TryParse(input, out int result)) { Console.WriteLine(result); } else { Console.WriteLine("Could not parse input"); }
24. 25 25 Pattern Matching
25. 26 5. Pattern Matching • 3 Types of Patterns – Constant Patterns if (o is null) return; // constant pattern "null" – Type Patterns if (!(o is int i)) return; // type pattern "int i" – Var Patterns • 2 C# language constructs – is – switch
26. 27 Patterns and Try-Methods object o = 7; if (o is int i || (o is string s && int.TryParse(s, out i))) { /* use i */ }
27. 28 switch Pattern public void PrintShape(object shape) { switch (shape) { case Circle c: Console.WriteLine($"circle with radius {c.Radius}"); break; case Rectangle s when (s.Length == s.Height): Console.WriteLine($"{s.Length} x {s.Height} square"); break; case Rectangle r: Console.WriteLine($"{r.Length} x {r.Height} rectangle"); break; default: Console.WriteLine("<unknown shape>"); break; case null: throw new ArgumentNullException(nameof(shape)); } }
29. 30 30 Local Functions
30. 31 6. Local functions // Fibonacci contains a local function Fib which cannot be called from the outside. // The local function has access to local variables and parameters of the outer function public int Fibonacci(int x) { if (x < 0) throw new ArgumentException("Less negativity please!", nameof(x)); return Fib(x).current; (int current, int previous) Fib(int i) { if (i == 0) return (1, 0); var (p, pp) = Fib(i - 1); return (p + pp, p); } }
31. 32 Local functions public IEnumerable<T> Filter<T>(IEnumerable<T> source, Func<T, bool> filter) { if (source == null) throw new ArgumentNullException(nameof(source)); if (filter == null) throw new ArgumentNullException(nameof(filter)); return Iterator(); IEnumerable<T> Iterator() { foreach (var element in source) { if (filter(element)) { yield return element; } } } }
32. 33 33 ref locals and ref returns
34. 35 static void Main(string[] args) { int[,] matrix = { { 1, 2 }, { 11, 12 }, { 21, 22 }, { 31, 32 }, { 41, 42 }, { 51, 52 } }; int item = Find(matrix, (val) => val == 42); // ref var item = ref Find(matrix, (val) => val == 42); Console.WriteLine(item); item = 24; Console.WriteLine(matrix[4, 1]); } public static ref int Find(int[,] matrix, Func<int, bool> predicate) { for (int i = 0; i < matrix.GetLength(0); i++) for (int j = 0; j < matrix.GetLength(1); j++) if (predicate(matrix[i, j])) return ref matrix[i, j]; throw new InvalidOperationException("Not found"); } 7. ref locals and ref returns
35. 36 static void Main(string[] args) { int[,] matrix = { { 1, 2 }, { 11, 12 }, { 21, 22 }, { 31, 32 }, { 41, 42 }, { 51, 52 } }; int item = Find(matrix, (val) => val == 42); // ref var item = ref Find(matrix, (val) => val == 42); Console.WriteLine(item); item = 24; Console.WriteLine(matrix[4, 1]); } public static ref int Find(int[,] matrix, Func<int, bool> predicate) { for (int i = 0; i < matrix.GetLength(0); i++) for (int j = 0; j < matrix.GetLength(1); j++) if (predicate(matrix[i, j])) return ref matrix[i, j]; throw new InvalidOperationException("Not found"); } 7. ref locals and ref returns
36. 37 static void Main(string[] args) { int[,] matrix = { { 1, 2 }, { 11, 12 }, { 21, 22 }, { 31, 32 }, { 41, 42 }, { 51, 52 } }; // int item = Find(matrix, (val) => val == 42); ref var item = ref Find(matrix, (val) => val == 42); Console.WriteLine(item); item = 24; Console.WriteLine(matrix[4, 1]); } public static ref int Find(int[,] matrix, Func<int, bool> predicate) { for (int i = 0; i < matrix.GetLength(0); i++) for (int j = 0; j < matrix.GetLength(1); j++) if (predicate(matrix[i, j])) return ref matrix[i, j]; throw new InvalidOperationException("Not found"); } 7. ref locals and ref returns
38. 39 39 More expression bodied members
39. 40 8. More expression bodied members public Person(string name) => names.TryAdd(id, name); // constructors ~Person() => names.TryRemove(id, out string s); // destructors public string Name { get => names[id]; // getters set => names[id] = value; // setters } // throw expressions public string GetLastName() => throw new NotImplementedException();
40. 41 41 public async Task<int>(…)
43. 44 44 ValueTask
44. 45 9. Async return Types private bool isIncache = false; private int cacheResult; public ValueTask<int> CachedFunc() { return isIncache ? new ValueTask<int>(cacheResult) : new ValueTask<int>(LoadCache()); } private async Task<int> LoadCache() { // simulate async work: await Task.Delay(100); cacheResult = 100; isIncache = true; return cacheResult; }
45. 46 C# 7 - Takeaways • Numeric Literals • Tuples • Deconstructor • Out Parameter • Pattern Matching • ref locals and ref returns (aka Pointer) • Local Functions • More expression bodied members (aka lambdas) • Async return Types
46. 47 47
47. 48 48 C# 7.1
48. 49 49 Visual Studio 2017 15.3 & .Net Core 2.0
49. 50 50 C# 7.1 is not enabled by default
50. 51 51
51. 52 52
52. 53 53
53. 54 54
54. 55 55
55. 56 56
56. 57 57 async main
57. 58 58
58. 59 59
59. 60 60 default
60. 61 61
61. 62 62 Infered tuples
62. 63 63
63. 64 64
64. 65 65
65. 66 66 Not impressed aka have a better idea?
66. 67 67 https://github.com/dotnet/csharplang
67. 68 68 The End
68. 69 Takeaways • Ensure your maximum productivity with new C# features • Give C# 7.1 a try if you want to • Give the team your feedback and suggestions https://github.com/dotnet/csharplang
69. 71 71 Thank you for coming and happy coding! @mallibone
70. Vielen Dank für Ihre Aufmerksamkeit! Mark Allibone mark.allibone@noser.com Hans-Peter Bornhauser hanspeter.bornhauser@noser.com