F# Discoveries This Week 10/03/2010

RickM — Mon, 04 Oct 2010 02:23:48 GMT

Just getting in from ICFP / CUFP and what a fantastic time it was. Mike Gordon’s ICFP tribute to Robin Milner left no one in the crowd untouched. CUFP had quite a few interesting F# related talks and they should be up on Vimeo soon.

I also want to mention that the F# community has three brand new Microsoft MVPs! Daniel Mohl, Talbott Crowell and Chris Marinos were awarded at just the beginning of this month. If you have twitter, please be sure to say hi and thank them for their hard work.

Lastly, I apologize for not posting last week. I used the time to refine my CUFP F# workshop. The contents of that workshop will be online within the next few days on my personal blog.

News

F# in Education Workshop - Microsoft Research (Nov 5th)

“The special reduced rate at the Liberty Hotel for workshop attendees is available for only a limited number of rooms and expires on October 15.”

Anton Tayanovskyy – Developing WebSharper 2.0 Applications at the New England F# User Group (October 4th)

“In this talk I will present a pre-release version of WebSharper 2.0 by developing and testing a small standalone JavaScript component.”

Audio and Video

Mike Gordon's Tribute to Robin Milner at ICFP 2010

“Officially titled "ML - metalanguage or object language", this invited talk by Mike Gordon (Cambridge) at the ACM International Conference on Functional Programming 2010 (Baltimore) really was a life story of Robin Milner and of ML.”

Use of F# at Microsoft Research

“An interview of David Stern and Jurgen Van Gael by David Brown”

An Introduction to F# with Don Syme (#1 of 4)

“Don, who created F#, introduces the language and describes the best way to begin developing with F#.”

An F# Tutorial with Don Syme (#2 of 4)

“Don, who created F#, demonstrates the language with live coding examples, such as analysing a real-time Twitter feed using F# Interactive.”

F# and Windows Azure with Don Syme (#3 of 4)

“Don, who created F#, demonstrates the language with live coding examples in F# Interactive, focussing on Windows Azure.”

F# in use at Microsoft Research (#4 of 4)

“- Project Emporia, which filters updates from the Twitter public feed and automatically develops topic-based “lenses”.
- AdCenter & AdPredictor, which determines the best adverts to display in Bing search results.
- The Path of Go, an AI implementation for the popular, ancient Chinese board game on XBOX 360.”

Tools

TickSpec (An F# BDD Framework) Oct 3 2001 Release

“Lots of new features” […] “Production Ready”

Fenetics is a simple F# library for genetic algorithms

“Fenetics is a simple F# library which demonstrates genetic algorithms in action, the name is a contraction of F(#) and (G)enetics. This is lab project and as such not a commercial component, not even a potential candidate but rather a slow move towards building enterprise-level F# libraries.”

General

Kean Walmsley's BrowsePhotosynth for AutoCAD

“For those of you interested in gory details, the code – which is installed with the application – is primarily in C# but also includes an F# module for downloading the various point cloud files asynchronously.”

Adam Granicz's Tutorial: Implementing a shopping cart with WebSharper

“The code provided here should work on any existing 1.0.X installation, preferably on the latest 1.0.28 release.”

Yin Zhu's F# and Data Mining: WekaSharp: more features

“This post will contain improvement over the minimal wrapper, e.g. more Dataset processing function, some plot functionality, etc”

Daniel Mohl's F#, Caliburn.Micro, and a New WP7 Template

“Ever since I first heard about Caliburn.Micro, I have wanted to build an F# template that used it. With
the new WP7 panorama C# template that was included in the RTW release of the Windows Phone Developer Tools, I found a good opportunity. ”

Daniel Mohl's Version 1.1 of the F# Windows Phone 7 Templates

“The two F# Windows Phone 7 templates (F# and C# Win Phone App (Silverlight) and F# and C# Win Phone List App(Silverlight)) have been updated to support Windows Phone Developer Tools RTW.”

Neil Carrier's More Novice F# Computation Expression Bind/Return Mechanics

“Today’s post is more F# “beginner” stuff I’m doing to help myself learn to think about workflows (or computation expressions as they are also called).”

Neil Carrier's F# Computation Expressions, Yield/For Mechanics

“Today’s episode of the ongoing computation expression saga features Yield/YieldFrom and For. One encounters fewer examples of these than of Bind/Return, though in most respects their operation is every bit as fundamental.”

Neil Carrier's F# Computation Expression Bind/Return Mechanics Continued.

“Isn’t it always the way? Almost as soon as I posted the previous entry, I came up with an example I like better. Rather than replace that example, I’ll just post the new one here.”

Neil Carrier's F# Computation Expressions, a Simple Bind/Return Mnemonic

“Below is one I’ve come up with for basic Bind/Return operation. It’s just a simple computation expression that increments a different column of a base ten number depending on the operation.”

Neil Carrier's F# Computation Expressions: Basic Data Retrieval Mechanics

“The test database itself consists of two record types. The first is a simple key/value pair. The second is a linking record type which consists of two keys. This keeps things simple for the test, but the method would remain the same even for more complex record structures.”

Neil Carrier's F# Workflow for Building Immutable Trees from Delimited Strings

“I really wanted to create an immutable version, but I lacked the skill with computation expressions at the time of the earlier post.”

Stefano Ricciardi's A RPN Calculator in F#

“While continuing my journey in F#, after playing with Project Eulero problems for a few weeks, I have come across another excellent excercise site which goes under the name of Programming Praxis.”

Joh's F# for game development: Final development stages of Asteroid Hunter

“Things are a bit slow on the XNA development front on my side these days. I have stopped adding features to Asteroid Hunter, and am now in the process of getting the last feedback from testers before submitting the game to peer review.”

Daniel Moore's Interview with Kalani Thielen: Trends in Programming Languages

“F#, Clojure, and Scala are all fairly new and popular languages this decade, the former two with striking resemblance to OCaml and Lisp, respectively, and the lattermost being more original in syntax. In what way do these languages represent forward thinking in language design, or how do they fail to build upon lessons learned in more venerable languages like Haskell?”

Alexander Rautenberg’s Stepping Stone Algorithm in F#, Part 1

“The calculations are mostly routine and not very interesting, but at the heart of it all is a little mechanism that I found lends itself to be coded in a very succinct and elegant way, with a few standard library calls and little more”

Alexander Rautenberg’s Stepping Stone Algorithm in F#, Part 2

“These are only a few points of information regarding the previous post.”

Matthew Manela's Functional stateful programming in F#

“While you may not always need the full power of the State monad, it along with explicit state passing are key tools for writing functional programs. With them you can approach many complex problems without the need for mutable state.”

Chris Marinos' C# Expressions vs. F# Quotations: A Syntax Comparison

“Now that I better understand some problems of implicit casting to expressions/quotations, I appreciate the explicit approach- even if I’m still not a big fan of the characters used to make the tags.”

Ian Voyce's Public static fields gone from F# 2.0

“The change itself is simple: static fields can no longer be public. Static fields can still be created, but they must be private.”

Teaching and Basics

Interactive Session #9: Processing XML

“Reading and interpreting XML data is performed through the System.Xml package. You need to create a new XmlDocument value and load the XML text into the XmlDocument.”

Interactive Session #10: List, Array, Sequence

“F# supports three different list-like data structures to store values of the same type: List, Array and Sequence. In this session we want to explore the similarities and differences among these three types.”

Interactive Session #11: Units of Measure

“F# includes a language feature to annotate your code with units of measure like meter, second or kilogram, preferably from the SI system. These units are statically checked during compile time and will not be part of the compiled code.”

Rick Minerich's Learning F# for Fabulous Prizes

“I found that the anticipation caused by not knowing when the next question might be asked kept attendees on their toes. Energy ran high throughout the session, higher than I’ve ever seen before.”

Ashley Feniello's Project Euler Problem #13

“It would be interesting to do without BigInts. Could use doubles with enough precision for just the first ten digits or some such thing, but just wanted the correct answer to plug into the site and I’m lazy :-)”

Ashley Feniello's Project Euler Problem #12

“First triangle number to have over five hundred divisors.”

Ashley Feniello's Project Euler Problem #11

“Greatest product of four adjacent numbers (up, down, left, right, or diagonally) in this 20x20 grid:”

Ashley Feniello's Project Euler Problem #10

“Easy problem, but way too slow (taking several minutes) with the naïve prime number generator from problem 7. This new version is 10x faster”

Community

Line of business applications: Will F# make my life easy?

“I am not asking whether it is possible to develop Line of Business application in F#. I am asking whether F# will make my life easier to develop Line of Business applications when compared to C#? My main concern will be threading & UI synchronization.”

How to limit the number of threads created for an asynchronous Seq.map operation in F#?

“The problem is, this tends to create too many threads and crash the application periodically”

Pattern matching on the beginning of a string in F#

“I am trying to match the beginning of strings in f#. Not sure if I have to treat them as a list of characters or what. Any suggestions would be appreciated”

F# Discoveries This Week 11/30/2009

RickM — Mon, 30 Nov 2009 16:44:58 GMT

A great deal going on this past week with Chris Smith releasing the source samples for Programming F#, Julien Ortin writing a spelling corrector, Matthew Moloney exploring the Azure worker role, Steve Gilham playing with NDepend and a flurry of Reactive Framework (Rx) posting by Matthew Podwysocki and Steffen Forkmann.

Chris Smith Releases the Source Code for Programming F#

I've gotten a few requests recently for the source code of the examples in Programming F#. I've attached them as a series of F# Script files.

Disclaimer: I tech edited a portion of this book and so may be a bit biased.

Now that that’s out of the way, you should know that this is currently the only book which is up to date with the plethora of F# API and language changes which have occurred over the past few months. That’s not to say that it’s not also fantastic in its own right, because it is.

At the very least giving these code samples a look is well worth your time.

Julien Ortin’s Simple Spelling Corrector in F#

This post is based on Peter Norvig’s How to write a spelling corrector, which is written in Python. His spell-checker ranks word-substitution candidates by their frequency in the language as determined by parsing some sources. He then gives different ways which could help make his algorithm more effective, such as taking the context into account (using n-grams).

Matthew Moloney’s Azure F# Worker Role with WCF

Azure now has support for input endpoints on Worker Roles! (Azure Tools Nov 2009) This is awesome as it greatly simplifies building WCF services in the cloud. As per usual, I’ve gone ahead and ported the most important components to F# and I have included a short list of some of the difficulties I had while doing so.

Steve Gilham’s Working on F# with NDepend

Following up from the earlier post here, looking more in depth at some of the results out of NDepend for my own little code quality project, and in addition to the results noted there.

Matthew Podwysocki’s Going Interactive with the Reactive Extensions

Lately in my series on the Reactive Extensions, you’ll have noticed I focused quite a bit on the IObservable<T> and IObserver interfaces as well as the extensions methods that are included. There is one thing, however, that might have been missed with the release of the Reactive Extensions is the inclusion of System.Interactive.dll. The idea behind this is to include many of the extension methods that are available to IObservable<T> and port them to work on the IEnumerable<T> interface.

Steffen Forkmann’s Mapping the Reactive Framework operators (Rx) for F#

The “Reactive Extensions for .NET (Rx)” comes with lot’s of operators for using IObservable<T>. This code mimics the signature of the default F# sequence combinators and allows to use observables like sequences.

and … Generating an IObservable<T> from an IEvent in F#

Yesterday I showed how we can map some of the Rx operators to an API which looks more like the F# base classes. Today I wanted to use these mapped operators in a WPF-application written in F#.

Rick Minerich's Development Wonderland : Azure, F#