functional-workshop

functional programming principles applied in C#

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Funcs

Funcs are another sugar syntax to create delegates that the .NET framework gives us. But these do have a generic return type, and can take up to sixteen generic parameters as input. The key difference between Actions and Funcs is that the last parameter of a Func which is the return type.

using System;
using System.Diagnostics;

internal static class TestFuncs
{
    internal static void Run()
    {
        // string -> string
        Func<string, string> consoleLoggerHandler = ConsoleLogger;
        Func<string, string> debugLoggerHandler = DebugLogger;
        Func<string, string> allConsoleHandlers = consoleLoggerHandler + debugLoggerHandler;

        var consoleResponse = consoleLoggerHandler("This goes to the console");
        var debugResponse = debugLoggerHandler("This goes to the debug");
        var lastResponse = allConsoleHandlers("this goes to all");
    }

    private static string ConsoleLogger(string message)
    {
        Console.WriteLine(message);
        return "Logged to console";
    }

    private static string DebugLogger(string message)
    {
        Debug.WriteLine(message);
        return "Logged to debug";
    }
}