The F# September 2008 CTP is now available!

I’m very pleased to announce the availability of the F# September 2008 CTP Release, launched via the new MSDN F# Developer Center. This release represents an important step in the evolution of the F# language as we progress it towards a fully supported language for the .NET platform. A huge thank you to both the F# team and the community members who’ve helped us trial earlier versions of this release and given us so much excellent feedback.


F# is a simple, type-safe, efficient, scalable language for the .NET platform that supports both functional and object-oriented programming. One of the key things about F# is that it spans the spectrum from interactive, explorative scripting to component and large-scale software development. In this release we’ve made major improvements to the language, libraries and tools across this spectrum.

Ø  Scripting now has added support, both in the language, compiler and Visual Studio. From simple touches such as “File -> New File -> F# Script” to the improved F# Interactive Tool Window and the new, MSBuild-based resolution rules for assembly references, our aim here is to put nothing between you and your ability to explore a problem space with F#. Jomo Fisher has more on scripting with F#.

Ø  The new and improved F# Project system enables large-scale, tool-based software development with F#. Teams can now develop large applications and libraries using standard Visual Studio techniques. This also makes F# easier to approach for developers familiar with Visual Studio. Brian McNamara has more on this.

Ø  The new F# Language Service gives more intuitive and reliable intellisense, type tips and smoother background compilation, all essential tools to assist in writing correct software

On the language side, some of the consistent feedback we get about F# is that the combination of type-inferred programming and interactive exploration allows you to develop correct algorithms and objects quickly and with a very low error rate. One of the things we’ve done in this release is to extend the reach of this combination to floating-point intensive domains through Units of Measure Inference and Checking. This allows you to tame the complexity of programs that manipulate floating point numbers representing physical and abstract quantities, without losing any performance in your compiled code. Floating point is an area of programming that has long resisted the benefits of typed programming, and you can think of this feature as providing a type system for floating point numbers. Andrew Kennedy has been a key contributor to this feature and will be following up with a blog series showing how to annotate your types with measure annotations and write code that is generic with respect to units, Luca Bolognese has a blog series showing some applications to financial code, and the F# Samples include a small 2D Solar System simulator using units.


In this release we’ve also continued the work begun in the April Refresh Release to make the F# language and libraries simpler and more regular. We’ve simplified both the F# Reflection and Quotation libraries, making them easier to learn and aligning them with the idioms and metaphors of the .NET Reflection API. We’ve also made some language extensions that simplify the working with object-oriented types in F#, and made the syntax of F# sequence and computation expressions more regular.


Finally, we’re also thinking about the future. As a step towards ensuring that the F# library has a component structure suitable for a maintained, supported release, we’ve split the F# library into two halves. The first is the core component FSharp.Core.dll. When the process of bringing F# to be a supported language completes, this library will version infrequently and have a very high compatibility bar, and will be sufficient to enable idiomatic F# application development. The second is a series of value-add components called the F# PowerPack. The PowerPack includes the FsLex and FsYacc tools, and DLLs for compatibility, math, dynamic execution and query functionality. The PowerPack will see more frequent updates than the core library and is designed to support continued innovation on top of the core F#.  It is the F# team’s plan of record that the F# PowerPack will be available as a shared source component on CodePlex during the same timeframe we bring F# to supported product quality.


We’ve also prepared detailed release notes for this release, and please let us know if you spot any issues!


Programming with F# can be enormously fun and rewarding, as well as just plain productive. This is now more true than ever, and we hope you enjoy using F# as much as we do.

Comments (40)

  1. – Don’s Announcement [ reddit ]

  2. MichaelGG says:

    I’ve been seeing the "really soon" posts and wow, THANK YOU. This is so exciting. Now we’ll have no use in any project.

  3. MichaelGG says:

    I’ve been seeing the "really soon" posts and wow, THANK YOU. This is so exciting. Now we’ll have no *barrier* to use in any project.

  4. A new version of the F# CTP was released today. There are a lot of new improvements to the language and

  5. awesome says:

    "Units of Measure Inference and Checking":  THANK YOU!  I’ve been waiting YEARS for something like this!

  6. Today we shipped the September CTP of F# !!!! Evviva !! Read this blog post about it. To celebrate I

  7. colder says:

    Today is a special day.

    It’s a sunny day! (although outside raining now)

    It’s a crazy day! (although quiet around me)

    It’s a sharp day!

    It’s a funny day!

  8. sparky says:

    Great work F# team. Can’t wait to dive into this.

  9. Anders Cui says:

    Can this version be integrated with VS 2005?

  10. Anders Cui says:

    F# September 2008 CTP发布了,这是F#进展过程的重要一步。

  11. Don Syme just announced today the F# Community Technical Preview (CTP) Release September 2008 which is

  12. Don Syme just announced today the F# Community Technical Preview (CTP) Release September 2008 which is

  13. Don Syme just announced today the F# Community Technical Preview (CTP) Release September 2008 which is

  14. Don Syme’s WebLog on F# and Other Research Projects : The F# September 2008 CTP is now available! F#,

  15. The September 2008 CTP of F# is now available for download.  F# is a functional programming language

  16. The September 2008 CTP of F# is now available for download.  F# is a functional programming language

  17. Eduardo says:


    I was trying some of the code in your book Expert F# with this new release, and get compilation errors. Specifically, String.Split is not recognized in the fsi. Can you suggest what DLLs need to be included, or what namespaces opened, in order for the code in your book to work with this latest release?


  18. Mike Gale says:

    That "Units of Measure Inference and Checking", caught my attention.  Having language support for this vital (and annoying) job really shows that somebody is paying attention to what some need.  (Instead of just doing the old conventional things with the same old conventional shortcomings.)

    Thanks very much.

  19. Wow, what a busy week!  The F# CTP is out the door, and it’s already making reverberations around

  20. Edit: Updated for the September CTP. With the September CTP hot off the presses , I figured it was time

  21. Ευχάριστα νέα για τους φίλους της F#, καθώς έχουμε στα χερια μας το πρώτο release της productized πλέον

  22. F# の September CTP (英語) がリリースされました。また同時に F# の Developer Center (英語) が公開されています。今回の F# に関しては Don Syme のブログ

  23. Tom Kirby-Green says:

    Fantastic news Don. Kudos to you and the team! Can’t wait to install this and start playing around.

  24. Microsoft acaba de liberar una nueva CTP del lenguaje F# tal y como podéis leer en el nuevo MSDN F# Developer

  25. Hi! I am happy to announce that The F# September 2008 CTP is now available for you all to get explored

  26. You’ve been kicked (a good thing) – Trackback from

  27. Hoping F# will be big success and make big wave in .net circle. The impovement side should be on intractive and as well as memory (stroage). Best of Luck!!!  

  28. Una piacevole novità ci attende al rientro dalle ferie (per chi ci è andato :-)): è stata

  29. Publicación del inglés original : Martes, 2 de septiembre de 2008 2:07 PM PST por Somasegar El pasado

  30. Seth says:

    Sweet! FSharp is a neat addition to the staple of .NET Languages

  31. Joel says:

    F# Community Technical Preview (CTP) 2008 was released! Good news!

  32. The September community technology preview (CTP) of F# marks an important step along the path to integrate

  33. F# Releases says:

    The F# Team has released the F# September 2008 CTP. Seeing F# followed by "CTP" is outstanding. …

  34. [原文地址]: F# September 2008 CTP Released [原文发表时间]:Tuesday, September 02, 2008 2:07 PM 去年 10 月, 我在 blog

  35. How many more languages we need actually! May be we should have a committee working on getting rid of some old ones as well.

  36. Julien says:

    Also thanks people at INRIA for the greatest language ever : OCaml ! F# is a microsoft implementation of OCaml, and it seems to be a *good thing*

  37. F# is the new kid on the block in terms of .NET languages.  Currently in CTP form , it will be one

  38. Brian Taylor says:

    2nd comment from someone going through your F# Expert book.  String.split is also unrecognized in my VS2008 environment.  From intellisense it looks like there is no string split function at all.  

  39. Tim says:

    I’ve just opened the book and ran the first example in VS 2008 and it doesn’t work…what an effing fail

    (I’m looking at and using errata and pulling in PowerPak, still fails)