FuncDemo

Extensens.cs

// 
// FuncDemos
// 
// Extensens.cs - 06.12.2012
// 
// Author:	glenn

using System;
using System.Net;

namespace FuncDemos
{
  public static class Extensens
  {
    public static T WithRetry<T>(this Func<T> action)
    {
      var result = default(T);
      int retryCount = 0;
      bool succees = false;

      do
      {
        try
        {
          result = action();
          succees = true;
        }
        catch (WebException ex)
        {
          retryCount++;
        }

      } while (retryCount < 3 && !succees);

      return result;
    }
    //
    // partial app
    public static Func<TResult> Partial<TParam1, TResult>(this Func<TParam1, TResult> func, TParam1 parameter)
    {
      return () => func(parameter);
    } 
    //
    // cuury
    // take func with N-Parameter and return func with N-Paramter - 1
    public static Func<TParam1, Func<TResult>> Curry<TParam1, TResult>( this Func<TParam1, TResult> func)
    {
      return parameter => () => func(parameter) ;
    } 
  }
}

FunDemo.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace FuncDemos
{
  class Program
  {
    static void Main(string[] args)
    {
      var output = 0;
      Func<int, bool> isNUll = i => ((i*i)%2) == 0;
      Func<string, Func<int, bool>, bool> isValid = (i, func) => int.TryParse(i, out output) && !func(int.Parse(i));
      var zahl = "3";
      var isTrue = isValid(zahl, isNUll);
      Console.WriteLine("value is : "+ isTrue);
      
      //
      // webClinet demo
      var client = new WebClient();

      Func<string, string> download = url => client.DownloadString(url);
      Func<string, Func<string>> downloadCurry = download.Curry();

      var data = download.Partial("http://wwww.20min.ch").WithRetry();
      var data2 = downloadCurry("http://www.20min.ch").WithRetry();
    }
  }
}