ythirion

public static Either<Exception, string> GetHtml(string url)
{
    var httpClient = new HttpClient(new HttpClientHandler());
    try
    {
        var httpResponseMessage = httpClient.GetAsync(url).Result;
        return httpResponseMessage.Content.ReadAsStringAsync().Result;
    }
    catch (Exception ex) { return ex; }
}

ythirion

static Func<string, string> GenerateGuidForUser = user => user + ":" + Guid.NewGuid();
static Func<string, string> GenerateGuidForUserMemoized = memo(GenerateGuidForUser);

[Fact]
public void memoization_example()
{
    GenerateGuidForUserMemoized("spongebob");// spongebob:e431b439-3397-4016-8d2e-e4629e51bf62
    GenerateGuidForUserMemoized("buzz");// buzz:50c4ee49-7d74-472c-acc8-fd0f593fccfe
    GenerateGuidForUserMemoized("spongebob");// spongebob:e431b439-3397-4016-8d2e-e4629e51bf62
}

ythirion

static Option<double> Half(double x)
    => x % 2 == 0 ? x / 2 : Option<double>.None;

[Fact]
public void bind_monad()
{
    Option<double>.Some(3).Bind(x => Half(x));// None
    Option<double>.Some(4).Bind(x => Half(x));// Some(2)
}

ythirion

  static Func<int, int> Add2 = x => x + 2;
  static Func<int, int> Add3 = x => x + 3;
  
  static int Add5(int x) => Add2.Compose(Add3)(x);

ythirion

new int[] { 2, 4, 6 }.Map(x => x + 3); // 5,7,9
new List<int> { 2, 4, 6 }.Map(x => x + 3); // 5,7,9
//Prefer use List (Immutable list)
List(2, 4, 6).Map(x => x + 3); // 5,7,9

ythirion

Option<int> aValue = 2;
aValue.Map(x => x + 3); // Some(5)

Option<int> none = None;
none.Map(x => x + 3); // None

//Left -> Some, Right -> None
aValue.Match(x => x + 3, () => 0); // 5
none.Match(x => x + 3, () => 0); // 0

ythirion

public class User
{
    public readonly Guid Id;
    public readonly string Name;
    public readonly int Age;

    public User(Guid id, string name, int age)
    {
        Id = id;
        Name = name;

ythirion

static int Double(int i) => i * 2;