简介

该库有助于以更实用的方式编写代码

安装

在NuGet上可用

dotnet add package CSharpFunctionalExtensions

或者

PM> Install-Package CSharpFunctionalExtensions

例子

Maybe

创建一个值

Maybe<string> apple = Maybe<string>.From("apple");

// or

Maybe<string> apple = Maybe.From("apple"); // type inference

// or

var apple = Maybe.From("apple");

GetValueOrDefault

void Response(string fruit)
{
    Console.WriteLine($"It's a {fruit}");
}

Maybe<string> apple = "apple";
Maybe<string> unknownFruit = Maybe<string>.None;

string appleValue = apple.GetValueOrDefault("banana");
string unknownFruitValue = unknownFruit.GetValueOrDefault("banana");

Response(appleValue); // It's a apple
Response(unknownFruitValue); // It's a banana

Where

bool IsMyFavorite(string fruit)
{
    return fruit == "papaya";
}

Maybe<string> apple = "apple";

Maybe<string> favoriteFruit = apple.Where(IsMyFavorite);

Console.WriteLine(favoriteFruit.ToString()); // "No value"

Map

string CreateMessage(string fruit)
{
    return $"The fruit is a {fruit}";
}

Maybe<string> apple = "apple";
Maybe<string> noFruit = Maybe<string>.None;

Console.WriteLine(apple.Map(CreateMessage).Unwrap("No fruit")); // "The fruit is a apple"
Console.WriteLine(noFruit.Map(CreateMessage).Unwrap("No fruit")); // "No fruit"

Select

Maybe<string> MakeAppleSauce(Maybe<string> fruit)
{
    if (fruit == "apple") // we can only make applesauce from apples 🍎
    {
        return "applesauce";
    }

    return Maybe<string>.None;
}

Maybe<string> apple = "apple";
Maybe<string> banana = "banana";
Maybe<string> noFruit = Maybe<string>.None;

Console.WriteLine(apple.Bind(MakeAppleSauce).ToString()); // "applesauce"
Console.WriteLine(banana.Bind(MakeAppleSauce).ToString()); // "No value"
Console.WriteLine(noFruit.Bind(MakeAppleSauce).ToString()); // "No value"

如对函数式编程感兴趣的小伙伴，请前往Github查看官方文档

github地址

https://github.com/vkhorikov/CSharpFunctionalExtensions

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