Rick Minerich's Development Wonderland : powerpack, fsharp

F# Discoveries This Week 05/28/2010

RickM — Fri, 28 May 2010 17:24:01 GMT

Come in and see what’s new in the F# world. Every week is seems there is ever more content on an increasingly wider variety of topics. The community is growing at a very fast pace. Because of this, I’ve decided to change things up a bit with a new format. I hope you’ll find it enhances your experience in exploring this mountain of fresh F# information.

News

Silverlight 4 runtime has been released with F# support

The F# PowerPack 2.0.0.0 is out and supports Silverlight 3 and 4

WebSharper 2010 1.0 is out and is free for commercial use

F# Project Extender 0.9.2.1 has been released

The CUFP 2010 and ML 2010 Call for Presentations is active

F# is on InformationWeek 500: 20 Great Ideas To Steal

Video / Audio

Don Syme Talks with Sadek Drobi About F# 2.0, a First Class Citizen in Visual Studio 2010

Don Syme speaks about F# 2.0, its application fields, its integration in Visual Studio 2010 and F# open source Power Pack library. Don also discusses the genesis of F#, the ties with OCaml as well as its specificity.

Don Syme Answering Questions on F#, C#, Haskell and Scala

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.

Amanda Laucher and Josh Graham – The state of the Art on .NET

Amanda Laucher and Josh Graham present at an introductory level some of the most important elements of the .NET ecosystem: F#, M, Boo, NUnit, RhinoMocks, Moq, NHibernate, Castle, Windsor, NVelocity, Guerilla WCF, Azure, MEF.

.NET Rocks F# Panel Live from NERD Center, Cambridge, MA

While on the Road Trip, Carl and Richard recorded this panel discussion with Talbott Crowell, Rick Minerich and Richard Hale Shaw on F# at the Microsoft New England Research and Development Center. The panel makes a very compelling case for adding a functional language to your toolchest.

Blogs

Brian McNamara’s Proggit Subreddit Graph in F# and DGML

Dear Proggit: graphs are cool, but I prefer F#, so I graphed the subreddit interconnections with F# and DGML

James’ Implementing map-reduce in F#

Again, F# proves to be a remarkably succinct language to express problems, in this case the built in syntactic sugar for tuples is a godsend!

Daniel Mohl’s F# ASP.NET MVC 2 Web Application Template and
Creating an F# Template for Visual Studio 2010

Tomas Petricek recently provided a great blog post on creating MVC web applications in F#. I thought it might be nice to also have a template that replicates the functionality of the standard C# ASP.NET MVC 2 Web Application template.

Daniel Mohl’s A Simple Inversion of Control (IoC) Container in F#

In this post I will show how to build a simple Inversion of Control (IoC) container in F#

Daniel Mohl’s Getting Started with WebSharper Platform 2010

A little while ago a cool new product was brought to my attention that allows client-based web development in F#. The name of this product is WebSharper Platform 2010. In this post, I will show a simple example for getting started with WebSharper Platform 2010.

Neil Carrier’s Computation Expressions with .NET Data Types

I’m still working on my proof-of-concept and it’s going well. One thing that’s been on my mind is the desire to use computation expressions in it somewhere. So I’ve been trying to make sure I understood computation expressions well enough to use them to good purpose.

Neil Carrier’s Active Pattern Activity and More Active Pattern Activity

I have to say the F# proof of concept is still going a lot better than I had ever hoped. Not only is it easy to port the basic algorithms from C# where applicable, but the kind of straightforward design that “functional-thinking” encourages is making for a better program with much less source code.

Phillip Trelford’s Exposing F# Dynamic Lookup to C#, WPF and Silverlight

Sometimes dynamic typing can be a pragmatic way of solving a specific problem. For example say you’re a solutions provider with a core product and have a number of clients with bespoke requirements. One client asks for a product rating feature. This can be relatively easily achieved using dynamic properties:

Phillip Trelford’s F# operator overloads for WPF dependency properties

Creating WPF elements directly from F# can produce good self-contained code, but at time is a little less readable than the XAML equivalent. Lets consider placing a button bound to a command on a grid at a certain position.

Clive Tong’s Towards an F# .NET Reflector add-in

When I had the opportunity to spent some time during Red Gate's recent "down tools" week on a project of my choice, the obvious project was an F# add-in for Reflector.

Clive Tong’s F# and the rose-tinted reflection

We're already seeing increasing use of many cores on client desktops. It is a change that has been long predicted.

Julien Ortin’s Technical analysis indicators in F# – Metadata and Reflection

In this part, we show how to use reflection to fetch the metadata attributes we have described in the first part of the technical analysis series.

Steve Gilham’s F# - excessively lazy sequences and stateful visitors

Doing something a little bit complicated here: the functional equivalent of a visitor pattern, where I want to apply a few functions to a long and potentially expensive to traverse sequence of items (so ruling out a series of iterations over the visited nodes)

Jon Harrop’s Mini hash table

Imagine you're stuck on a desert island with only a few keystrokes and you desperately need to create your own rudimentary hash table. What might you do?

Jomo Fisher’s How to Enumerate all WMI Classes

This is the F# code you would use to enumerate all WMI classes on your system and show the properties of each. of each.

Fredrik Holmstrom’s F# short hand syntax for maps and sets

I’ve always though it a shame that there is no in language short hand syntax for maps and sets in F#, something like {{foo = 1; bar = 2}} and {#1, 2#} – but having a very flexible language at my disposal I set out to find some way to achieve this, mostly for fun – but maybe someone will find a practical use of it.

Community

From StackOverflow: Scala vs F#, How do they unify OO and FP?

What are the key differences between the approaches taken by Scala and F# to unify OO and FP paradigms?

From StackOverflow: F# Static Member Type Constraints

I'm trying to define a function, factorize, which uses structural type constraints (requires static members Zero, One, +, and /) similar to Seq.sum so that it can be used with int, long, bigint, etc. I can't seem to get the syntax right, and can't find a lot of resources on the subject. This is what I have, please help.

F# Discoveries This Week 02/25/2010

RickM — Thu, 25 Feb 2010 21:31:07 GMT

Between Atalasoft, Professional F# 2.0 and the MVP Summit I’ve been completely swamped and ended up with quite a backlog of posts. Between the Brian-Chris F# Code Battle, Luca’s LChart, Ashley’s continuing FScheme series and Matthew’s MongoDB stuff I’m not sure I can pick a favorite. That’s not true, I’d go right for the DAWG-fight series. The arcane secrets of F# optimization await inside.

C9 Lectures: Dr. Don Syme - Introduction to F#, 3 of 3

In Part 3 of this 3-part lecture series, Dr. Don Syme elaborates further on: Patterns, Object Basics, [and] Imperative Programming.

Dr. Don Syme’s Async and Parallel Design Patterns in F#: Agents

In part 3 of this series, we explore lightweight, reactive agents in F# and look at some typical design patterns associated with these agents, including isolated internal state.

Chris Smith’s DAWG-fight, Optimizing text search in F# II and Dr. Brian McNamara’s DAWG-Gone (F# Language Team Code Battle Summary)

So today I’ll walk you through what Chris did right (shortest… subsection… ever!), as well as what he did wrong (get comfy in your chair), and then show my own implementation.

Luca Bolognese’s LChart: Displaying Charts in F# Parts One, Two and Three

I want to use F# as a exploratory data analysis language (like R). But I don’t know how to get the same nice graphic capabilities. So I decided to create them. Here is a library to draw charts in F#.

Dr. Brian McNamara’s An RSS Dashboard in F# Parts Four, Five and Six.

You can see from the colors in the screenshot from part one what I desired, but this requires knowing which links are ‘visited’ and which are not, so I can color each link appropriately. It turns out, this information can be had via unusual means…

Ashley Feniello’s FScheme Parts Ten and Eleven

We’re now taking the first small step into the world of nondeterministic logic programming (chapter 16 of Bill Hails’ book). Hopefully you enjoyed the last post about continuation passing and found the idea to be ripe with potential power; indeed so powerful that we’re going to use it now to bifurcate the universe! No really, we are…

Luca Bolognese’s A simpler F# MailboxProcessor

I always forget the pattern to use to create a functioning MailboxProcessor in F#. I mean, which piece has to be async and how to structure the recursive loop. When I find myself in that kind of a situation situation, my instincts scream at me: “Wrap it and make it work how your mind expects it to work”. So here is a simplification of the paradigm.

Matthew Podwysocki’s The F# PowerPack Released on CodePlex

As announced yesterday, the new February 2010 release of F# is out. This release is much more of a stabilization release instead of adding a lot of features including improvements in tooling, the project system and so on.

Matthew Podwysocki’s Exploring MongoDB with F#

I just want a quick answer with the data I have. There was one issue of course that nagged me which was the ubiquitous use of strings for everything from databases, collections, and keys. With a language such as F#, could we do any better than this approach?

Matthew Podwysocki’s F# and the Dynamic Lookup Operator ala C#

In the F# language, we have the ability to define two “dynamic” operators, a get member operator denoted by the ( ? ), and the set member operator denoted by the ( ?<- ). The F# language and its associated libraries do not have an actual implementation of these operators, but instead allow you to implement them as you see fit.

Steve Gilham’s Updating F# posts to 1.9.9.9 Parts One and Two

Possibly a few more issues will come out as I reconstitute my analysis tool, which is currently undergoing a retooling of its build system to automate some of the manual checks for whether the operational tests succeeded or not.

Steffen Forkmann’s FAKE – F# Make 0.29 Released

Last week I released version 0.29 of my build automation tool “FAKE – F# Make”. The new version comes along with a couple of changes which I will now describe.

Luis Diego Fallas’s Using a Webcam with DirectShowNET and F#

In this post I'm going to show a small F# example of using DirectShowNET to access a webcam and manipulate the image data.

Mark Needham’s F#: Passing an argument to a member constraint

I've written previously about function overloading in F# and my struggles working out how to do it and last week I came across the concept of inline functions and statically resolved parameters as a potential way to solve that problem.

Julien Ortin’s BitTorrent Bencoded values and BitTorrent Metainfo file handling in F#

Byte strings can be strings represented as byte strings (such as the description of the exchanged data), as well as an array of bytes (such as a hash). Representing them with the .Net strings can thus lead to errors. Hence we shall keep the byte array representation.

Julien Ortin continues his series on Purely Functional Data Structures with a Skew binomal heap, a Banker’s double-ended queue, a Alternative binary random access list, a Bootstrapped queue, and a Implicit queue.

This post describes the F# implementation of the <insert data structure here> from Chris Okasaki’s “Purely functional data structures”.

Scott Seely’s F# is Changing My Style

The types I’m interested are concrete (no abstract methods) and have a zero-argument constructor. A few years ago, I would have done a bunch of looping constructs to look at each element. However, I’ve been doing a lot more work with F#. While doing this experiment in C# for a project, I wound up writing the following instead:

Steve Gilham’s It almost feels like cheating…

Having renamed all the .c files as .cpp, getting a first building assembly was simple, and then making it refer to an initially empty F# library, no problem; and then setting up an (again, initially empty) unit test assembly depending on both (where vice-tests to match up new and old implementations, and their eventual unit test replacements can accumulate), just as normal.

Brad Clow’s F# Examples talk at BFG

Earlier this week I gave a short talk at the Brisbane Functional Group on F#. The idea was to give an introductory feel for the language by way of some simple examples.

Phillip Trelford’s F# Talk at Edge UG: Slides and Demos

I presented a 1 hour talk introducing F# with 4 demos (attached to this post): Full-screen WPF POS Checkout sample with Barcode scanner integration (in 100 lines). Twitter WPF client script (200 lines). Matermind board game in WPF (300 lines). Lunar Lander XNA game (>400 lines).

Matt Jackson’s AssertWasCalled in F# (or how I learned to stop worrying and hate extension methods)

Unfortunately, this upcasting led me on a short goose chase to find out which interface in the Rhino Mocks codebase was responsible for AssertWasCalled only to realise that it was an extension method sitting hiding away somewhere else.

Discoveries This Week 06/14/2009

RickM — Mon, 15 Jun 2009 00:09:00 GMT

Another great week in F#. Most importantly, it is now known that the language will continue to be available for free, despite productization. Also, the F# PowerPack is now available for VS2010 beta and the MSDN documentation is up.

Tore Green asks Don Syme “will F# continue to be freely available?”

Free options will continue to exist, most likely through the VS shell. For example, we'll be continuing with our VS2008 plugin until the plans around a VS2010 shell finalize.

It is very good to hear that the productization of F# won’t stop it from continuing to be available for free.

Tomas Petricek’s WebCast – Using Asynchronous Workflows

Now that Visual Studio 2010 Beta 1 is out, it is finally a good time to take a look at one of the (in my opinion) most interesting new features in the new release - the F# language.

In this Webcast, Tomas shows how simple it is to add asynchronous operation to an application via the F# asynchronous workflow feature.

F# PowerPack Beta 1 for .NET 4.0/Visual Studio 2010 is Available.

F# PowerPack is now available for download for the latest Beta development milestones of the next generation of Microsoft's development platform and tools.

I know a great many people (not to mention myself) were disappointed that the VS 2010 beta did not ship with this. I for one am in love with it’s Math and Charting features.

Visual F# MSDN Documentation

The Visual F# product provides support for developing F# applications or extending other .NET applications with F# code.

We now have official documentation in the MSDN style we all know and love.

F# – You can overload operators, but you can’t use them.

^ (op_Concatenate): Compiler error in F#. Apparently only strings can be concatenated.

> (op_GreaterThan): Runtime Error – Failure during generic comparison: the type Program+OppTest4 does not implement the System.IComparable interface.

It’s not what you say but how you say it, and while I feel the reaction of the author was way over the top, his concerns seem justified. I’m hoping it’s just a bug and, now being identified, will be resolved.