Updated readme

Author: jirkapok

FunctionalCsharp/readme.md

@@ -1,6 +1,58 @@
 # Functional C#
 
-* Examples based on following sources:
+## Definition of C# z WIKI
+* https://en.wikipedia.org/wiki/C_Sharp_(programming_language)
+* Multi-paradigm: structured, imperative, object-oriented, event-driven, task-driven, functional, generic, reflective, concurrent
+* https://www.amazon.com/Functional-Programming-write-better-code/dp/1617293954
+
+
+## Already build in
+* Delegates and lambdas (C# 3)
+```csharp
+persons.Where(p => p.IsRetired)
+```
+
+* Static usings (C# 6)
+```csharp
+using static System.Math;
+double result = Pow(2, 3);
+```
+
+* Nonnullable (C# 8)
+```csharp
+string? nickname = null;
+```
+
+* Immutables (record C# 9+)
+```csharp
+public record Person(string Name, DateOnly BirthDate);
+```
+
+* Pattern matching (C# 7-11)
+```csharp
+  if (obj is string s) ...
+  if (person is { Age: > 18, Name: var n }) ...
+  var result = shape switch
+  {
+  Circle c => "circle",
+  _ => "Unknown shape"
+  }
+```
+
+## The good parts
+* Linq lambas (Dotnet 3.5 2007) - tragedie představená v roce 2017: lokální funkce
+* Exception handling (Try object)
+* Result Type (https://dotnet.github.io/dotNext/features/core/result.html)
+* Option instead of Null (https://dotnet.github.io/dotNext/features/core/optional.html)
+* Discriminated unions (Most awaited feature) https://www.youtube.com/watch?v=tD46WVJ2h9I&ab_channel=NickChapsas
+
+
+## Examples Implementations
+* Used language-ext and OneOf nugets
+* Others: Functional.DotNet, Funcky, FunCs, Fambda, Farity or other exotic implementations like FuncSharp
+
+
+## Examples based on following sources
   * [FuncSharp library](https://github.com/MewsSystems/FuncSharp)
   * [The New Option and Result Types of C#](https://www.youtube.com/watch?v=aksjZkCbIWA)
   * [Result pattern in medatr](https://goatreview.com/improving-error-handling-result-pattern-mediatr/)