F# Documentation - Visual Studio Community

Welcome to the official documentation for F#, a powerful, open-source, functional-first programming language developed by Microsoft. F# is designed to be robust, concise, and performant, making it an excellent choice for a wide range of applications, from data science and machine learning to web development and enterprise services.

Getting Started with F#

Begin your F# journey with these essential resources:

Installation: Learn how to install F# and the necessary components for Visual Studio Community.
Your First Program: Write and run a simple F# application to get a feel for the syntax and workflow.
Project Structure: Understand the typical F# project layout and how to manage your code.

// Hello, World! in F#
    printfn "Hello, F# World!"

Core F# Language Features

Dive deep into the functional programming paradigm with F#:

Immutability by Default: Understand how F# encourages safe and predictable code through immutable data structures.
Pattern Matching: Leverage powerful pattern matching for elegant data decomposition and control flow.
Type Inference: Experience concise code without sacrificing type safety thanks to F#'s advanced type inference.
Asynchronous Workflows: Build scalable and responsive applications using F#'s built-in support for asynchronous programming.
Object-Oriented Programming: While functional-first, F# seamlessly integrates with .NET and supports object-oriented patterns.

Immutability

F# variables are immutable by default. You use the let keyword for defining values that cannot be changed after their initial assignment.

let message = "This is immutable"
    // Trying to reassign will result in a compile-time error:
    // message <- "New value"

Pattern Matching

Pattern matching allows you to deconstruct data and execute code based on its shape.

let describeNumber n =
        match n with
        | 0 -> "Zero"
        | 1 -> "One"
        | _ when n < 0 -> "Negative"
        | _ -> "Positive"

    printfn "%s" (describeNumber 5) // Output: Positive
    printfn "%s" (describeNumber 0) // Output: Zero

Visual Studio Integration

Visual Studio Community provides a rich and seamless development experience for F#:

IntelliSense: Advanced code completion, parameter info, and quick hints.
Debugging: Step through your F# code, inspect variables, and set breakpoints.
Project Templates: Quickly scaffold new F# projects for various application types.
F# Interactive (FSI): Execute F# code snippets interactively and test logic on the fly.
Unit Testing: Integrate with popular unit testing frameworks like FSUnit and xUnit.net.

F# Ecosystem and Tools

Explore the vibrant F# ecosystem:

NuGet Package Manager: Access a vast collection of F# libraries and tools.
.NET Libraries: Leverage the full power of the .NET Framework and .NET Core.
Build Tools: Use dotnet CLI and F# build targets for automation.
Web Frameworks: Discover frameworks like Saturn and Giraffe for building web applications.
Data Science: Utilize libraries like Deedle for data manipulation and ML.NET for machine learning.

Tutorials and Examples

Enhance your F# skills with practical examples and step-by-step guides: