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The past couple of years have seen some extended debates on whether Scala is a functional language. On the one hand, Scala offers essentially all programming constructs typically associated with functional programming and a lot of Scala code is purely functional. On the other hand quite a few people disagree that Scala is a functional language. For instance, Robert Fischer writes that Scala is Not a Functional Programming Language and Daniel Spiewak summarizes some of the arguments asking Is Scala Not Functional Enough?

F# is Microsoft's first functional programming language to be included as one of Visual Studio's official set of languages. F# is a succinct, efficient, expressive functional/object-oriented programming language under joint development by Microsoft Developer Division and Microsoft Research. During the course of Erik Meijer's fantastic lecture series on functional programming fundamentals several of you asked for examples of specific topics in F#. Well, we listened. Dr. Don Syme is a principal researcher in MSR Cambridge. He has a rich history in programming language research, design, and implementation (C# generics being one of his most recognized implementations), and is the principle creator of F#. Who better to lecture on the topic than Don? This three part series will serve as an introduction to F#, including insights into the rationale behind the history and creation of Microsoft's newest language.

We had to cover monads eventually, and there are many great monad tutorials out there (see, for example, here: http://www.haskell.org/haskellwiki/Tutorials#Using_monads). In fact, there are web resources concerned solely with organizing the many monad tutorials available in the wild, and developing new monad tutorials seems to be a popular sport in the Haskell community.Today, Ralf Lämmel's lecture goes back to the roots, essentially revisiting Wadler's "The essence of functional programming"—the 1992 paper that discovered monads and popularized their use in functional programming. Ralf Lämmel's lecture and accompanying code distribution show Wadler's seminal insight: those original scenarios and observations still make sense today. Indeed, Simon Marlow (a Haskell/GHC high priest @ MSR Cambridge) recently noted: "it's still the best monad tutorial" (see http://twitter.com/simonmar/status/21397398061).

You would be forgiven if you thought the "F" in F# -- which made its debut as part of Visual Studio 2010 -- stands for "functional." After all, F# (pronounced "F sharp") is a functional programming language for the .NET Framework that combines the succinct, expressive, and compositional style of functional programming with the runtime, libraries, interoperability, and object model of .NET. But Don Syme, inventor of F# and leader of the team that incubated the language, has a different, truncated, and entirely whimsical definition. "In the F# team," says Syme, a principal researcher at Microsoft Research Cambridge, "We say, 'F is for Fun.' F# enables users to write simple code to solve complex problems. Programming with F# really does make many programming tasks simpler, and our users have consistently reported that they've found using the language enjoyable." Indeed, F#, which has been developed in a partnership between Microsoft Research and the Microsoft Developer Division, is already popular with the .NET developer community. The language is widely known in the academic community and among thought leaders, and the list of admirers will only increase as Visual F#, the result of a partnership between Microsoft Research Cambridge and Microsoft's Developer Division, becomes a first-class language in Visual Studio 2010.

In functional programming, monadic characterizations of computational effects are normally understood denotationally: they describe how an effectful program can be systematically expanded or translated into a larger, pure program, which can then be evaluated according to an effect-free semantics. Any effect-specific operations expressible in the monad are also given purely functional definitions, but these definitions are only directly executable in the context of an already translated program. This approach thus takes an inherently Church-style view of effects: the nominal meaning of every effectful term in the program depends crucially on its type. We present here a complementary, operational view of monadic effects, in which an effect definition directly induces an imperative behavior of the new operations expressible in the monad. This behavior is formalized as additional operational rules for only the new constructs; it does not require any structural changes to the evaluation judgment. Specifically, we give a small-step operational semantics of a prototypical functional language supporting programmer-definable, layered effects, and show how this semantics naturally supports reasoning by familiar syntactic techniques, such as showing soundness of a Curry-style effect-type system by the progress+preservation method.

Scala is a general purpose programming language principally targeting the Java Virtual Machine. Designed to express common programming patterns in a concise, elegant, and type-safe way, it fuses both imperative and functional programming styles. Its key features are: statically typed; advanced type-system with type inference; function types; pattern-matching; implicit parameters and conversions; operator overloading; full interop with Java

cala is a general purpose programming language principally targeting the Java Virtual Machine. Designed to express common programming patterns in a concise, elegant, and type-safe way, it fuses both imperative and functional programming styles. Its key features are: statically typed; advanced type-system with type inference; function types; pattern-matching; implicit parameters and conversions; operator overloading; full interop with Java

Building a dynamic PHP site requires you to understand how CRUD (create, read, update, delete) functions work. There are a variety of ways to implement these functions include databases, and most commonly through mySQL.  With these functions you can add new entries to the database (registration), view existing entries (retrieve users or fields), update the entries to your table or delete users (who may unsubscribe or permanently delete their accounts.) For a user account based sites, these functions are essential for keeping your user and information database up to date.

F# is the only language to be added to Visual Studio for a very long time. What makes it so special? There is a growing trend to include elements of functional programming in “mainstream” languages such as C#. If functional programming is so good this raises the question of why we don’t just move to a functional language. After all, there is an ideal candidate, F# which is a true .NET based language. So, is F# very different? Let’s find out.

Introducing Functional Programming Server-Side Functional Programming Developing Client-Side Applications Numerical Computing Working with Data Visualizing Data with .NET Charts

One of the common discussions that I've had with several colleagues when we're making use of some of the higher order functions that can be applied on collections is whether to use the LINQ style syntax or to chain the different methods together. I tend to prefer the latter approach although when asked the question after my talk at Developer Developer Developer I didn't really have a good answer other than to suggest that it seemed to just be a personal preference thing. Damian Marshall suggested that he preferred the method chaining approach because it more clearly describes the idea of passing a collection through a pipeline where we can apply different operations to that collection.

There's much excitement about JDK 7 and in particular Lambdas! I've waded through the bloat to help you get an understanding of it. If you search for JDK 7 in your favourite search engine the chances are you'll hit the controversies surrounding lambadas in Java fairly early on in your hunt. It's a contentious subject, which means it's getting a lot of attention from a lot of clever people, but this in turn makes the process slow and adds difficulty in making decisions. My take is that lambdas will be in JDK 7 - you can see plenty of evidence of that around the web and in the snapshot builds. That said, no decision is concrete (which is a wise tip from The Pragmatic Programmer no less!). This article is aimed at those who don't know much about functional programming or what Lambdas, Closures or Currying are and want to get 'primed'.

In ASP.NET development, F# also offers productivity advantages over VB and C#.  F# is different because it is statically checked and type-safe.  It addresses weaknesses in ASP.NET development like untyped values, complex form construction, and using strings for IDs and method names that connect markup with code-behind (class-files).  Writing a web application in F# on the WebSharper platform can be less-time consuming if a developer is not great at writing web apps in JavaScript.  Through WebSharper, developers can write a web app using a large subset of F# and .NET core libraries and then just let WebSharper map the code to JavaScript.  WebSharper can integrate with ASP.NET applications, but it is different from the standard approach because it builds applications from miniature web pages called "pagelets".  The pagelets correspond to functions on the client-side and they are automatically translated into JavaScript.   WebSharper supports a wide range of JavaScript libraries, making it easy for developers to optimize their code in whatever way they choose.  jQuery, qooxdoo, Flapjax, and Yahoo UI are all supported by WebSharper.  The leap from F# to JavaScript is manageable because both are functional languages that support lambda expressions and closures.  Another unique part of WebSharper is a "formlet".  A formlet is a special pagelet that provides form functionality.  Formlets in Web Sharper run and validate on the client, submitting their result to a either a client- or a server-side callback.

Starting from Visual Studio 2010 F# is full member of .NET Framework languages family. It is functional language with syntax specific to functional languages but I think it is time for us also notice and study functional languages. In this posting I will show you some examples about cool things other people have done using F#.

F# is ideal for data-rich, concurrent and algorithmic development: "simple code to solve complex problems". F# is a simple and pragmatic programming language combining functional, object-oriented and scripting programming, and supports cross-platform environments including PC, Mac, and Linux. We'll provide the tutorials, resources and tools you’ll need to begin working with F# right away.

As many long time readers know, I am an enthusiast of the F# programming language.  I make no apologies for the fact that, if you are developing software on the .NET platform, F# is one of the better choices you can make for numerous reasons.  It is one of the reasons I proudly contributed as a co-author to the book, Professional F# 2.0, which is being published by Wrox in October. Some of the oft cited benefits of F# are that, to distill them quickly, it is good at doing intensely mathematical operations, it is built for parallelism, and it is good at helping define domain specific languages.  Those benefits are so often cited by speakers on the F# speaker circuit that they pretty much seem cliche to me at this point (note, yours truly is proud to call himself a member of said circuit, and often gives this talk!)  As great as these features are, there are a couple features, that in my more mundane F# experiences, seem to stand out as things that “save my ass”, for lack of a better phrase, more often than not.

In this interview made by InfoQ’s Sadek Drobi, Don Syme, a Senior Researcher at Microsoft Research, answers questions mostly on F#, but also on functional programming, C# generics, type classes in Haskell, similarities between F# and Scala.

Today sees the launch of Visual Studio 2010, at five launch events around the world, as announced by Bob Muglia, Jason Zander and S. Somasegar, and presented live today in Las Vegas.   Visual Studio 2010 includes the official version 2.0 of the F# language. As is our custom on the F# team, we also release a matching MSI and ZIP of F# 2.0 (for use with Visual Studio 2008 and as a standalone compiler on a range of platforms)   Today represents the culmination of 7 years of work on the language at Microsoft Research, and, more recently, the Microsoft Developer Division. I am immensely proud of what we’ve achieved. F# brings a productive functional and object-oriented programming language to .NET, extending the platform to new audiences in technical, algorithmic, data-rich, parallel and explorative domains, and its inclusion in Visual Studio 2010 represents a huge milestone for the language.   To help understand what we’re doing with F#, I’ve listed some of the common questions people have about the language below.  We thank everyone who has been involved in the production of F#, especially the many users who have given us feedback on the language!

We describe a practical method for reasoning about realistic concurrent programs. Our method allows global two-state invariants that restrict update of shared state. We provide simple, sufficient conditions for checking those global invariants modularly. The method has been implemented in VCC, an automatic, sound, modular verifier for concurrent C programs. VCC has been used to verify functional correctness of tens of thousands of lines of Microsoft's Hyper-V virtualization platform and of SYSGO's embedded real-time operating system PikeOS.