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Code samples for Functional Programming in C#
https://github.com/la-yumba/functional-csharp-code

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Code samples for Functional Programming in C#

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README 

        
# Functional Programming in C# #



This repo contains the code samples, exercises and solutions for the book

[Functional Programming in C#](https://www.manning.com/books/functional-programming-in-c-sharp?a_aid=functional-programming-in-c-sharp&a_bid=ad9af506)

published by Manning.



[![Functional Programming in C#](cover.jpg)](https://www.manning.com/books/functional-programming-in-c-sharp?a_aid=functional-programming-in-c-sharp&a_bid=ad9af506)



The code samples are organized in the following projects:



- **Examples**: examples used throughout the book, by chapter

- **Exercises**: placeholders for you to do the exercises, compile and run them;

  and compare to the provided solutions

- **LaYumba.Functional**: a functional library that we develop throughout the book

- **LaYumba.Functional.Data**: very simple functional data structures discussed in Chapter 9

- **LaYumba.Functional.Tests**: also illustrative of topics explained in the book, and

  useful to better understand the constructs in the library

- **Boc.Domain**: an example of using F# for domain objects



**Note:** you are welcome to reference `LaYumba.Functional` from your projects

via [NuGet](https://www.nuget.org/packages/LaYumba.Functional), and submit

PRs with improvements, but the main intent of this library is pedagogical.

For a more fully-fledged functional library, consider [LanguageExt](https://github.com/louthy/language-ext)



## Working with the code samples



The code samples use .NET Standard 1.6 and .NET Core 2.0, and should compile and run on all major OS's

via the `dotnet` CLI.



### Prerequisites



- [.NET Core 2.0.3 SDK](https://www.microsoft.com/net/download/core)



To check this is available, type `dotnet --version` at the command prompt, and you should get `2.0.3` or greater



### One-time setup



```

$ git clone [email protected]:la-yumba/functional-csharp-code.git

$ cd functional-csharp-code

$ dotnet restore

```



### Running the tests



Use the `dotnet test` command, for example:



```

$ cd LaYumba.Functional.Tests

$ dotnet test

```



tests in the `Exercises` and `Examples` projects can be run in the same way.



### Running examples



Many code samples in the book can be run, in case you'd like to debug or "see that it works".

The pattern is:



```

$ cd Examples

$ dotnet run Greetings

```



| Section | Command

|---:| ---

| 7.1 | `dotnet run Greetings`



## Setting up the REPL



Throughout the book, I encourage readers to try things out in the [REPL](https://en.wikipedia.org/wiki/Read%E2%80%93eval%E2%80%93print_loop).



- If you use Visual Studio, you can start the REPL by going to

`View > Other Windows > C# Interactive` (short tutorial [here](https://github.com/dotnet/roslyn/wiki/C%23-Interactive-Walkthrough))

- On Mono, use the `csharp` command

- There are several other REPLs available, some even run in the browser



You'll often need to import `LaYumba.Functional` in the REPL. In C# Interactive,

this can be done like so:



```csharp

#r "functional-csharp-code\LaYumba.Functional\bin\Debug\netstandard1.6\LaYumba.Functional.dll"

```



The path above may not work for you, in which case use an absolute path to the dll,

or type `Directory.GetCurrentDirectory()` into the REPL to see what to use as a base for a relative path.



Next, add these imports:



```csharp

using LaYumba.Functional;

using static LaYumba.Functional.F;

```



You're now ready to experiment with functional code right in the REPL, for example:



```csharp

> Func plus = (a, b) => a + b;

> Some(plus).Apply(1).Apply(2)

[Some(3)]

> Some(plus).Apply(1).Apply(None)

[None]

```



## Doing the exercises



- edit the code in `Exercises` as needed

- edit `Exercises/Program.cs` to start the class you want

- run it with:



  ```

  $ cd Exercises

  $ dotnet run

  ```

- run your tests:



  ```

  $ cd Exercises

  $ dotnet test

  ```