F# (programming language)

F# (programming language)
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Name	F#
Paradigm	Functional, imperative, object-oriented, metaprogramming, concurrent, type-safe
Designer	Don Syme, Microsoft Research
Developer	Microsoft, The F# Software Foundation
Latest release version	8.0.0
Latest release date	14 November 2023
Typing	Inferred, static, strong
Influenced by	OCaml, C#, Haskell
Influenced	F*
Operating system	Cross-platform
License	MIT License
Website	https://fsharp.org/

F# (programming language). F# is a strongly typed, functional-first programming language that runs on the .NET platform. Developed initially at Microsoft Research under the leadership of Don Syme, it aims to combine the succinctness and expressiveness of functional languages like OCaml with the robustness and interoperability of the Microsoft .NET Framework. It is an open-source, cross-platform language supported by both Microsoft and the community-driven The F# Software Foundation.

History

The genesis of F# can be traced to research at Microsoft Research in Cambridge, where Don Syme and his team sought to bring functional programming to the .NET Common Language Runtime. Influenced heavily by the ML (programming language) family, particularly OCaml, the first version was released as part of Microsoft Visual Studio 2010. A pivotal moment in its evolution was its transition to open-source governance, culminating in the establishment of The F# Software Foundation to steward its development independent of Microsoft. Key milestones include its integration into Xamarin for mobile development and its adoption as a fully supported language for cloud development on the Microsoft Azure platform.

Features

F# is distinguished by its functional-first paradigm, emphasizing immutability and first-class functions to facilitate concise and predictable code. Its advanced Type inference system, inherited from OCaml, minimizes the need for explicit type annotations while ensuring Type safety. The language seamlessly integrates Asynchronous programming primitives, like Async workflows, and supports Computation expressions for creating domain-specific languages. Other notable features include Pattern matching, Units of measure for scientific computing, and robust support for Metaprogramming via Type providers, which enable rich IntelliSense and data integration directly from external sources like SQL databases or JSON schemas.

Syntax and examples

F# syntax is lightweight and indentation-sensitive, omitting verbose punctuation common in languages like C#. A simple function to calculate a factorial demonstrates its conciseness, using Pattern matching on an integer argument. List processing is idiomatic, utilizing the pipe-forward operator (`|>`) to chain operations, a style popularized in Functional programming circles. For interoperability, F# can directly consume types and libraries from the entire .NET Framework, including those written in C# or Visual Basic .NET. Type providers allow developers to write code against live data sources, such as a SQL Server database, with compile-time safety and editor support akin to working with static types.

Development tools

The primary integrated development environment for F# is Microsoft Visual Studio, which offers deep tooling support including IntelliSense, debugging, and project templates. For cross-platform and lightweight editing, Visual Studio Code with the Ionide extension provides a rich experience on macOS and Linux. The core compiler and tools are distributed via the .NET SDK, and build automation is typically handled by FAKE, an F#-specific build system. Package management is facilitated through NuGet, and the interactive programming environment FSI (F# Interactive) allows for rapid scripting and data exploration, commonly used in data science scenarios alongside tools like Jupyter Notebooks.

Applications and adoption

F# has found significant adoption in domains requiring high correctness and complex data transformation, such as quantitative finance, where institutions like Credit Suisse have utilized it for modeling and risk analysis. Its strengths in data science and analytics are leveraged through libraries like Deedle and integration with the Apache Spark ecosystem via .NET for Apache Spark. Within Microsoft, it is used for internal tools and services on the Microsoft Azure cloud platform. The language is also popular for developing web applications, using frameworks like Saturn or Giraffe atop ASP.NET Core, and for cross-platform mobile apps via the F# Mobile Apps template in Xamarin.

Category:Programming languages Category:Functional languages Category:.NET programming languages Category:Microsoft development tools