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TDC2018SP | Trilha .Net - Novidades do C# 7 e 8

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TDC2018SP | Trilha .Net - Novidades do C# 7 e 8

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TDC2018SP | Trilha .Net - Novidades do C# 7 e 8

  1. 1. w w w. l a m b d a 3 . c o m . b r Novidades do C# 7 e 8
  2. 2. Giovanni Bassi • Programador • Microsoft MVP • Não gerente • blog.lambda3.com.br, podcast.lambda3.com.br, dotnetarchitects.net, nodebr, dockersp @giovannibassi /giggio.tech • Escalador e ciclista
  3. 3. podcast.lambda3.com.br 0 – Eventos 1 – Docker 2 – .NET Core RC2 3 – Git 4 – Estudo 5 – Open Source 6 – Xamarin 7 – Node.js 8 – Democracia organizacional 9 – O programador poliglota ... Toda semana em:
  4. 4. Acreditamos que a diversidade, em suas diversas expressões, deve ser respeitada e valorizada, e que uma sociedade mais diversa é uma sociedade melhor. diversidade.tech
  5. 5. bit.ly/novidadescsharp7
  6. 6. Agenda
  7. 7. Evolução do C#
  8. 8. Código gerenciado Generics Language Integrated Query Dinamismo + paridade nas linguagens C# 5 + VB 11 Programação assíncrona C# 1 + VB 7 C# 2 + VB 8 C# 3 + VB 9 C# 4 + VB 10 C# 6 + VB 14 Roslyn
  9. 9. Código gerenciado Generics Language Integrated Query Dinamismo + paridade nas linguagens C# 5 + VB 11 Programação assíncrona C# 1 + VB 7 C# 2 + VB 8 C# 3 + VB 9 C# 4 + VB 10 C# 6 + VB 14 Roslyn C# 7 + VB 15 Features!
  10. 10. Código gerenciado Generics Language Integrated Query Dinamismo + paridade nas linguagens C# 5 + VB 11 Programação assíncrona C# 1 + VB 7 C# 2 + VB 8 C# 3 + VB 9 C# 4 + VB 10 C# 6 + VB 14 Roslyn C# 7 + VB 15 Features! Features! Features!Features!
  11. 11. Código gerenciado Generics Language Integrated Query Dinamismo + paridade nas linguagens C# 5 + VB 11 Programação assíncrona C# 1 + VB 7 C# 2 + VB 8 C# 3 + VB 9 C# 4 + VB 10 C# 6 + VB 14 Roslyn C# 7 + VB 15 Features! Features! Features! Features (parte 2)? C# 8 + VB 16?
  12. 12. https://insights.stackoverflow.com/survey/2018/#most-popular-technologies
  13. 13. https://insights.stackoverflow.com/survey/2018/#most-popular-technologies
  14. 14. F# 10,000’s Tens of thousands VB 100,000’s Hundreds of thousands C# 1,000,000’s Millions
  15. 15. System.ValueTuple
  16. 16. <PropertyGroup> <LangVersion>latest</LangVersion> </PropertyGroup>
  17. 17. C# 7.0
  18. 18. public static int DiceSum(IEnumerable<object> values) { var sum = 0; foreach (var item in values) { if (item is int val) sum += val; else if (item is IEnumerable<object> subList) sum += DiceSum(subList); } return sum; } https://docs.microsoft.com/dotnet/csharp/pattern-matching http://bit.ly/cspatternmatching
  19. 19. https://docs.microsoft.com/dotnet/csharp/pattern-matching public static int DiceSum(IEnumerable<object> values) { var sum = 0; foreach (var item in values) { switch (item) { } } return sum; } http://bit.ly/cspatternmatching
  20. 20. case 0: break; case int val: sum += val; break; case PercentileDie die: sum += die.Multiplier * die.Value; break; https://docs.microsoft.com/dotnet/csharp/pattern-matching public static int DiceSum(IEnumerable<object> values) { var sum = 0; foreach (var item in values) { switch (item) { } } return sum; } http://bit.ly/cspatternmatching
  21. 21. case 0: break; case int val: sum += val; break; case PercentileDie die: sum += die.Multiplier * die.Value; break; https://docs.microsoft.com/dotnet/csharp/pattern-matching case IEnumerable<object> subList when subList.Any(): sum += DiceSum(subList); break; case IEnumerable<object> subList: break; case null: break; default: throw new InvalidOperationException("unknown"); public static int DiceSum(IEnumerable<object> values) { var sum = 0; foreach (var item in values) { switch (item) { } } return sum; } http://bit.ly/cspatternmatching
  22. 22. var numbers1 = (1, 2); var objs = ("1", 2); WriteLine($"{numbers1.Item1}, {numbers1.Item2}"); (int one, int two) numbers2 = (1, 2); WriteLine($"{numbers2.Item1}, {numbers2.Item2}"); WriteLine($"{numbers2.one}, {numbers2.two}"); var numbers3 = (one: 1, two: 2); WriteLine($"{numbers3.one}, {numbers3.two}"); (int uno, int due) numbers4 = (one: 1, two: 2); WriteLine($"{numbers4.uno}, {numbers4.due}"); // WriteLine($"{numbers4.one}, {numbers4.two}"); // error https://docs.microsoft.com/dotnet/csharp/tuples http://bit.ly/cstuplas
  23. 23. void M() { var (name, company) = Person.Get(); WriteLine($"{name}, {company}"); } class Person { public string Name { get; set; } public string Company { get; set; } public void Deconstruct(out string name, out string company) { name = Name; company = Company; } public static Person Get() => new Person { Name = "…", Company = "…" }; } https://docs.microsoft.com/dotnet/csharp/tupleshttp://bit.ly/cstuplas
  24. 24. var numbers = (one: 1, two: 2); var (uno, due) = numbers; WriteLine($"{uno}, {due}"); https://docs.microsoft.com/dotnet/csharp/tuples http://bit.ly/cstuplas
  25. 25. if (int.TryParse("1", out int result)) WriteLine(result); if (int.TryParse("1", out var result2)) WriteLine(result2); https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#out-variables http://bit.ly/csoutvars
  26. 26. (int x, int y) GetCoordinates() => (1, 2); var (_, y) = GetCoordinates(); https://docs.microsoft.com/dotnet/csharp/discards http://bit.ly/csdiscards
  27. 27. void ObjectDeconstruction() { var (name, _) = Person.Get(); } https://docs.microsoft.com/dotnet/csharp/discards http://bit.ly/csdiscards
  28. 28. if (int.TryParse("1", out _)) WriteLine("It is a number!"); https://docs.microsoft.com/dotnet/csharp/discards http://bit.ly/csdiscards
  29. 29. object o = 1; if (o is Person p) WriteLine(p.Company); else if (o is null) WriteLine("null"); else if (o is var _) WriteLine("Unknown"); https://docs.microsoft.com/dotnet/csharp/discards http://bit.ly/csdiscards
  30. 30. 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"); } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#ref-locals-and-returns http://bit.ly/csreflocals
  31. 31. void M() { var matrix = new [,] { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 42, 10 } }; ref var item = ref Find(matrix, val => val == 42); WriteLine(item); item = 24; WriteLine(matrix[1, 3]); } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#ref-locals-and-returns http://bit.ly/csreflocals
  32. 32. public ExpressionBodiedMembers(string name) => Name = name; ~ExpressionBodiedMembers() => WriteLine("Finalized!"); private string name; public string Name { get => name; set => name = value; } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#more-expression-bodied-members http://bit.ly/csmaisebm
  33. 33. private string a = GetA() ?? throw new Exception(); private static string GetA() => throw new Exception(); https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#throw-expressions http://bit.ly/csexpthrow
  34. 34. int sixteen = 0b0001_0000; int thirtyTwo = 0b0010_0000; int sixtyFour = 0b0100_0000; int oneHundredTwentyEight = 0b1000_0000; long oneHundredBillions = 100_000_000_000; double AvogadroConstant = 6.022_140_857_747_474e23; decimal GoldenRatio = 1.618_033_988_749M; https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#numeric-literal-syntax-improvements http://bit.ly/csnumlit
  35. 35. double Average(IEnumerable<int> ns) { double Divide(double a, double b) { if (b == 0) throw new DivideByZeroException(); return a / b; } var sum = ns.Sum(); return Divide(sum, ns.Count()); } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#local-functions http://bit.ly/cslocalfunc
  36. 36. void Add1AndSumAll(int[] ms) { IEnumerable<int> Sum1(IEnumerable<int> ns) { foreach (var n in ns) yield return n + 1; } if (ms == null) throw new NullReferenceException(); WriteLine(Sum1(ms).Sum()); } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#local-functions http://bit.ly/cslocalfunc
  37. 37. public async ValueTask<int> Get5() { await Task.Delay(100); return 5; } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#generalized-async-return-types http://bit.ly/csasyncgeneral
  38. 38. public async ValueTask<int> SumAsync(IEnumerable<ValueTask<int>> ns) { var sum = 0; foreach (var nTask in ns) { var n = await nTask; sum += n; } return sum; } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7#generalized-async-return-types http://bit.ly/csasyncgeneral
  39. 39. C# 7.1
  40. 40. var x = (f1: 1, f2: 2); var tuple = (x.f1, x.f2, x); https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7-1#inferred-tuple-element-names http://bit.ly/cstuplainfer
  41. 41. Func<string, bool> predicate = default; int i = default; N(default); https://docs.microsoft.com/dotnet/csharp/programming-guide/statements-expressions-operators/default-value-expressions http://bit.ly/csliteraldefault
  42. 42. (int, int) N(int[] ns = default) => default; string O() { return default; } T P<T>() { T t = default; return t; } https://docs.microsoft.com/dotnet/csharp/programming-guide/statements-expressions-operators/default-value-expressions http://bit.ly/csliteraldefault
  43. 43. static async Task<int> Main(string[] args) { await Task.Delay(500); WriteLine("Done"); return 0; } https://docs.microsoft.com/dotnet/csharp/whats-new/csharp-7-1#async-main http://bit.ly/csasyncmain
  44. 44. C# 7.2
  45. 45. void M(int i, int j) { } void N() { M(i: 2, 3); } https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/non-trailing-named-arguments.md http://bit.ly/csntna
  46. 46. var m = 0b_101; //5 var n = 0x_00C0; // 192 https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/leading-separator.md http://bit.ly/cs_num
  47. 47. class Base { private protected int f; } class DerivedInSameAssembly : Base { void M() { var x = base.f; } } class DerivedInOtherAssembly : Base { void M() { var x = base.f; //error } } https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/private-protected.md http://bit.ly/csprpr
  48. 48. Vector Add(in Vector v1, in Vector v2) { v1 = default(Vector); // not OK!! v1.X = 0; // not OK!! Foo(ref v1.X); // not OK!! // OK: return new Vector(v1.X +v2.X, v1.Y + v2.Y); } https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types http://bit.ly/csmodin
  49. 49. https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/readonly-ref.md#refin-extension-methods public static Ponto Soma(in this Ponto p1, in Ponto p2) => new Ponto(p1.X + p2.X, p1.Y + p2.Y); void In() { Ponto p1 = new Ponto(1, 2), p2 = new Ponto(3, 4); var pResultado = p1.Soma(p2); var pResultado2 = p1.Soma(new Ponto(3, 4)); var pResultado3 = new Ponto().Soma(new Ponto(3, 4)); } http://bit.ly/csmodin
  50. 50. public static Ponto Subtrai(ref this Ponto p1, ref Ponto p2) => new Ponto(p1.X - p2.X, p1.Y - p2.Y); void Ref() { Ponto p1 = new Ponto(1, 2), p2 = new Ponto(3, 4); var pResultado = p1.Subtrai(ref p2); p1.Subtrai(ref new Ponto()); // não compila new Ponto().Subtrai(ref p1); // não compila } https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/readonly-ref.md#refin-extension-methods http://bit.ly/csextref
  51. 51. https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/readonly-ref.md#refin-extension-methods public static void Foo<T>(ref this T p1) where T : struct { } http://bit.ly/csextref
  52. 52. ref readonly Vector FetchOrigin() => ref origin; void M() { var v1 = new Vector(1, 2, 3); var v2 = new Vector(4, 5, 6); var vSum = Add(v1, v2); ref readonly var origin = ref FetchOrigin(); } private readonly Vector origin = new Vector(0, 0, 0); https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types http://bit.ly/csretrefro
  53. 53. ref readonly var origin = ref FetchOrigin(); var origin2 = FetchOrigin(); // copy created https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types http://bit.ly/csretrefro
  54. 54. readonly struct Ponto { public Ponto(float x, float y) { X = x; Y = y; } public float X { get; } public float Y { get; } private readonly static Ponto origem = new Ponto(); public static ref readonly Ponto Origem => ref origem; } https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types#readonly-struct-type http://bit.ly/csrostruct
  55. 55. ref readonly var p = ref Ponto.Origem; var x = p.X; // sem cópia https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types#readonly-struct-type http://bit.ly/csrostruct
  56. 56. ref int M() { var arr = new[] { 1, 2, 3 }; var otherArr = new[] { 4, 5, 6 }; ref var r = ref (arr != null ? ref arr[0]: ref otherArr[0]); Foo(ref (arr != null ? ref arr[0]: ref otherArr[0])); (arr != null ? ref arr[0]: ref otherArr[0]) = 1; return ref (arr != null ? ref arr[0]: ref otherArr[0]); } void Foo(ref int i) => i = 42; https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.2/conditional-ref.md http://bit.ly/csternarioref
  57. 57. ref struct TwoSpans<T> { // pode ter campos desde que não sejam classes public Span<T> first; public Span<T> second; } // erro: arrays of ref-like types are not allowed. TwoSpans<int>[] arr = null; https://docs.microsoft.com/en-us/dotnet/csharp/reference-semantics-with-value-types#ref-struct-type
  58. 58. readonly ref struct ReadOnlyRefPoint2D { public int X { get; } public int Y { get; } public ReadOnlyRefPoint2D(int x, int y) => (X, Y) = (x, y); } https://docs.microsoft.com/dotnet/csharp/reference-semantics-with-value-types#readonly-ref-struct-type
  59. 59. void M() { Span<int> arr = stackalloc int[3]; } https://msdn.microsoft.com/en-us/magazine/mt814808.aspx Não é unsafe
  60. 60. C# 7.3
  61. 61. Span<int> RowFive = new Span<int>(PascalsTriangle, 10, 5); fixed (int* ptrToRow = RowFive) { // Soma os números 1,4,6,4,1 var sum = 0; for (int i = 0; i < RowFive.Length; i++) { sum += *(ptrToRow + i); } Console.WriteLine(sum); } https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/pattern-based-fixed.md int[] PascalsTriangle = { 1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 5, 10, 10, 5, 1 }; Span<T>.GetPinnableReference()
  62. 62. unsafe struct S { public fixed int myFixedField[10]; } class C { private static S s = new S(); unsafe public void M() { int p = s.myFixedField[5]; } } https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#indexing-fixed-fields-does-not-require-pinning // CSharp 7.2 fixed (int* ptr = s.myFixedField) { int p = ptr[5]; }
  63. 63. var structs = new StructGrande[] { new StructGrande(), new StructGrande() }; ref StructGrande refLocal = ref structs[0]; refLocal = ref structs[1]; https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#ref-local-variables-may-be-reassigned
  64. 64. unsafe void M() { int* pArr = stackalloc int[3] { 1, 2, 3 }; int* pArr2 = stackalloc int[] { 1, 2, 3 }; Span<int> arr = stackalloc[] { 1, 2, 3 }; } https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-3#stackalloc-arrays-support-initializers
  65. 65. unsafe public static byte[] ToByteArray<T> (this T argument) where T : unmanaged { var size = sizeof(T); var result = new byte[size]; byte* p = (byte*)&argument; for (var i = 0; i < size; i++) result[i] = *p++; return result; } https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/generics/constraints-on-type-parameters#unmanaged-constraint
  66. 66. public static TDelegate TypeSafeCombine<TDelegate> (this TDelegate source, TDelegate target) where TDelegate : System.Delegate => System.Delegate.Combine(source, target) as TDelegate; Action first = () => Console.WriteLine("this"); Action second = () => Console.WriteLine("that"); var combined = first.TypeSafeCombine(second); combined(); https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/generics/constraints-on-type-parameters#delegate-constraints
  67. 67. public static Dictionary<int, string> EnumNamedValues<T>() where T : System.Enum { var result = new Dictionary<int, string>(); var values = Enum.GetValues(typeof(T)); foreach (int item in values) result.Add(item, Enum.GetName(typeof(T), item)); return result; } enum Rainbow { Red, Orange, Yellow, Green, Blue, Indigo, Violet } var map = EnumNamedValues<Rainbow>(); foreach (var pair in map) Console.WriteLine($"{pair.Key}:t{pair.Value}"); https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/generics/constraints-on-type-parameters#enum-constraints
  68. 68. https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/expression-variables-in-initializers.md var t1 = (1, 2); var t2 = (3, 4); var iguais = t1 == t2; var diferentes = t1 != t2;
  69. 69. https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/expression-variables-in-initializers.md var query = from text in strings select int.TryParse(text, out int value) ? value : (int?)null;
  70. 70. public class Foo { protected Foo(out int i) => i = 1; } public class Bar : Foo { public int Value { get; } public Bar() : base(out int value) => Value = value; } https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/expression-variables-in-initializers.md
  71. 71. public class Baz { private readonly int field1 = int.TryParse(SomeStatic.Text, out int value) ? Value : -1; } https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/expression-variables-in-initializers.md
  72. 72. https://github.com/dotnet/csharplang/blob/master/proposals/csharp-7.3/auto-prop-field-attrs.md [Serializable] public class Foo { [field: NonSerialized] public string MySecret { get; set; } }
  73. 73. C# 8.0
  74. 74. public class Cartesian { public int X { get; } public int Y { get; } } public class Polar { public static bool operator is(Cartesian c, out double R, out double Theta) { R = Math.Sqrt(c.X * c.X + c.Y * c.Y); Theta = Math.Atan2(c.Y, c.X); return c.X != 0 || c.Y != 0; } } void M() { var c = new Cartesian(3, 4); if (c is Polar(var R, _)) WriteLine(R); } https://github.com/dotnet/csharplang/blob/master/proposals/patterns.md
  75. 75. void N(string? aNullableString, bool condition) { WriteLine(aNullableString.Length); // warning if (aNullableString != null) WriteLine(aNullableString); // no warning if (!string.IsNullOrWhiteSpace(aNullableString)) WriteLine(aNullableString!.Length); // I know better var anotherNullableString = condition ? "Hello" : aNullableString; WriteLine(anotherNullableString.Length); // warning var yetAnotherNullableString = condition ? "Hello" : null; WriteLine(yetAnotherNullableString.Length); // warning string nonNullableString = null; //warning WriteLine(nonNullableString); // no warning } https://github.com/dotnet/csharplang/blob/master/proposals/nullable-reference-types.md https://github.com/dotnet/roslyn/blob/features/NullableReferenceTypes/docs/features/NullableReferenceTypes/README.md
  76. 76. async Task M() { foreach await (var i in GetStream()) WriteLine(i); } IAsyncEnumerable<int> GetStream() => new[] { 1, 2, 3 }.ToAsyncEnumerable(); async IAsyncEnumerable<int> MyIterator() { for (int i = 0; i < 100; i++) { await Task.Delay(1000); yield return i; } } https://github.com/dotnet/csharplang/blob/master/proposals/async-streams.md
  77. 77. using await (IAsyncDisposable resource = await store.GetRecordAsync(…)) { … } class Foo : IAsyncDisposable { public async Task DisposeAsync() { await ... } } https://github.com/dotnet/csharplang/blob/master/proposals/async-streams.md
  78. 78. interface I { void M() { WriteLine("I.M"); } } class C : I { } // OK void M() { I i = new C(); i.M(); // prints "I.M" } https://github.com/dotnet/csharplang/blob/master/proposals/default-interface-methods.md
  79. 79. Dictionary<string, List<int>> field = new() { { "item1", new() { 1, 2, 3 } } }; XmlReader.Create(reader, new() { IgnoreWhitespace = true }); https://github.com/dotnet/csharplang/blob/master/proposals/target-typed-new.md
  80. 80. // list[Index.CreateFromEnd(1)] var ultimoItem = list[^1]; // list[Index.CreateFromEnd(2)] var penultimoItem = list[^2]; // list[3, Index.CreateFromEnd(2)] var multiDimensional = list[3, ^2]; https://github.com/dotnet/csharplang/blob/master/proposals/ranges.md
  81. 81. // list[Range.Create(2, Index.CreateFromEnd(3))] var slice1 = list[2..^3]; // list[Range.ToEnd(Index.CreateFromEnd(3))] var slice2 = list[..^3]; // list[Range.FromStart(2)] var slice3 = list[2..]; // list[Range.All] var slice4 = list[..]; // list[Range.Create(1, 2), Range.All] var multiDimensional = list[1..2, ..] https://github.com/dotnet/csharplang/blob/master/proposals/ranges.md
  82. 82. class Person : IEquatable<Person> { public string First { get; } public string Last { get; } public Person(string First, string Last) => (this.First, this.Last) = (First, Last); public void Deconstruct(out string First, out string Last) => (First, Last) = (this.First, this.Last); public bool Equals(Person other) => other != null && First == other.First && Last == other.Last; public override bool Equals(object obj) => obj is Person other ? Equals(other) : false; public override int GetHashCode() => GreatHashFunction(First, Last); … } class Person(string First, string Last); https://github.com/dotnet/csharplang/blob/master/proposals/records.md
  83. 83. extension class Enrollee extends Person { // static field static Dictionary<Person, Professor> enrollees = new Dictionary<Person, Professor>(); // instance method public void Enroll(Professor supervisor) { enrollees[this] = supervisor; } // instance property public Professor Supervisor => enrollees.TryGetValue(this, out var supervisor) ? supervisor : null; // static property public static ICollection<Person> Students => enrollees.Keys; // instance constructor public Person(string name, Professor supervisor) : this(name) { this.Enroll(supervisor); } } https://github.com/dotnet/csharplang/issues/192
  84. 84. public shape SGroup<T> { static T operator +(T t1, T t2); static T Zero { get; } } https://github.com/dotnet/csharplang/issues/164
  85. 85. public static AddAll<T>(T[] ts) where T : SGroup<T> { var result = T.Zero; foreach (var t in ts) { result += t; } return result; } https://github.com/dotnet/csharplang/issues/164
  86. 86. public shape SGroup<T> { static T operator +(T t1, T t2); static T Zero { get; } } https://github.com/dotnet/csharplang/issues/164
  87. 87. w w w. l a m b d a 3 . c o m . b r Obrigado! Giovanni Bassi @giovannibassi /giggio.tech

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