Rick Minerich's Development Wonderland : async

F# Discoveries This Week 09/17/2010

RickM — Fri, 17 Sep 2010 20:25:06 GMT

ICFP approaches quickly and I’m working hard to make that those four hours of CUFP F# tutorial will be well worth your time. Meanwhile I’ve gathered the best the of the F# community for your enjoyment. Dig in!

News

September 23rd at CUFPx Michigan - Mark Harris: "A Commercial Deployment of F# "

“Mark Harris, formerly of Microsoft, currently working for Grange Insurance in Columbus, Ohio, will be presenting a case study of a commercial deployment of an F# solution. One of the highlights of this deployment--a process which took 18 hours was cut down to 6 minutes. Mark will be discussing the benefits and drawbacks of using F# in Grange's commercial app.

Audio and Video

Deep Fried Bytes Technology Podcast Episode 60: The Futures of the F# Language with Luke Hoban

“In this episode Keith and Woody sit down with F# Program Manager Luke Hoban at TechEd 2010 to discuss the futures of the F# language. Luke gave the guys the scoop on what developers can accomplish with F# and what the team has planned for upcoming releases of F# with Visual Studio.”

General

Dmitri Nesteruk 's Making DSLs in F#

“This article shows that making a DSL in F# is really simple. Of course, the thing about DSLs is they are domain-specific, so for the domain you choose you might encounter a lot more challenges. Have fun!”

Neil Carrier's Basic F# Computation Expressions Using Yield and Combine

“I decided to learn a little bit about computation expressions beyond the basic Bind/Return operations. So I made a goal of learning something about the Yield/Combine operations.”

Neil Carrier's F# Async Computation Expressions: A Tiny Model System

“Continuing my quest to learn computation expressions, I decided to explore from scratch the implementation of basic asynchronous behavior. This post is the result.”

Robert Pickering's What is object oriented programming really all about?

“People often ask me what functional programming is all about and why is it useful. In an attempt to answer this question in a way that is relevant to object oriented programmers it struck me it might be useful to look at what people find useful in modern object oriented programming.”

Celso Axelrud's Vector, Matrix and Linear Algebra in F#

“The following script snippets present the vector and matrix functionalities in Microsoft.Fsharp.Numerics namespace from Fsharp.PowerPack assemble.”

Daniel Markham's Functional TDD: Codd is my Copilot

“You work for the IRS. Your job today is to select a list of people with large bank balances so that you can do some kind of indescribably-complex tax-stuff to them. Your boss would like a list of these guys on his desk by noon.”

Vladimir Matveev's Slides And Samples

“Presentation and code samples from my recent talk on FSUG meeting.”

Stefano Ricciardi's Project Euler Problem 10 in F#

“Calculate the sum of all the primes below two million.”

Ashley Feniello's Project Euler Problem #8

“Largest products of five consecutive digits in this 1000-digit number.”

Ashley Feniello's Project Euler Problem #9

“Pythagorean triplet where a + b + c = 1000”

Ray Dacoco's TabControl in Visual F#

“TabControl is a control that can be used to organize information. It can be utilized as a good alternative to menustrip control.”

Ray Dacoco's Changing the Pointer when the mouse hovers an object

“To change the mouse pointer when the mouse hovers an object, use the Cursor property. All form controls in Visual F# has Cursor property.”

Community

StackOverflow - Does Functional Programming Replace GoF Design Patterns?

“Functional languages have plenty of best practice rules of the form "when you encounter problem X, use code that looks like Y", which is basically what a design pattern is.”

StackOverflow - F# Type declaration possible ala Haskell?

“If you want to keep readable type declarations separately from the implementation, you can use 'fsi' files (F# Signature File).”

A Look Outside

Chris Waggoner's Category Theory

“Category Theory is like Set Theory, but supposedly better. What is it, though?”

F# Discoveries This Week 08/27/2010

RickM — Sat, 28 Aug 2010 00:04:06 GMT

I’m back again with another edition of F# Discoveries this Week. The most exciting announcement this week is the new F# August 2010 CTP which brings with it the ability to build your own VS2010 F# Express Edition with Visual Studio Shell and the prospect of building F# applications on Windows Phone 7. Be sure to check out Daniel Mohl’s Windows Phone 7 template before getting started.

News and Upcoming Talks

F# (August 2010 CTP)

Announcing the F# 2.0 Standalone Tools Update

A standing invitation to F# users to "get in touch"

Don Syme lecturing at the F#unctional Londoners Meetup (9/9)

Tools and Libraries

WekaSharp: An F# wrapper for Weka (Yin Zhu)

F# and C# Win Phone List Template (Silverlight) (Daniel Mohl)

fsai Release FSharp AI library 1.10.0 (Lukáš Kouřil)

RockScroll: my new favourite Visual Studio Add-In (Kean Walmsley)

Video, Audio and Slides

Slides and samples from F# talk in Manchester (Oliver Sturm)

F# Intro Talk at NextGenUG in So’ton (Phillip Trelford)

Slides from Combinators, DSLs, HTML, and F# (Robert Pickering)

Busy .NET Developer’s Guide to F#: Basics (Ted Neward)

Technical Articles

iTunes via F# Interactive (Cameron Taggart)

F# for puzzles (Morse code decoder) (Brian McNamara)

Extracting elements from Win32 resource files (Luis Diego Fallas)

A variation on Matt Moloney's "Memento" pattern (Don Syme)

Bound Variables in F#: What Reflection Reveals (Neil Carrier)

Getting F# Running on a Continuous Integration Server (Ade Miller)

How F#'s async really works? (George Cullen)

Segment Tree in F# (Neil Carrier)

Bound Variables in F#: What Reflection Reveals (Neil Carrier)

Fuzzy Logic Experiments in F# (Neil Carrier)

Fuzzy Logic in F#, Example 1 (Neil Carrier)

Fuzzy Logic in F#, Now More Functional! (Neil Carrier)

F# “fun” with Windows Phone 7 (Fahad)

Getting started with Windows Phone in F# (Senthil Kumar)

Euler Problem 10 (Mark Pearl)

Euler Problem 16 (Mark Pearl)

Project Euler Problem 9 in F# (Stefano Ricciardi)

Project Euler Problem 8 in F# (Stefano Ricciardi)

Project Euler Problem 6 and 7 in F# (Stefano Ricciardi)

Enumerable.Skip vs Seq.skip (Mauricio Scheffer)

Getting Started and Evangelism Articles

Putting the fun in functional programming (Daniel Markham)

Back to school : Getting to know F# (Mehfuz Hossain)

Learning F# by writing C# (Alan Hemmings)

F# - sharper than C# (Josh Reuben)

Learning F# for C# developers (Bill Morrissey)

F# Community

Ars Technica - What do you think of F# ?

SO - How to merge sorted sequences in F#.

SO - Which to use, C# or F#? In this "real world" case

hubFS: F# Databse Application Samples & Articles

hubFS: MailboxProcessor.TryScan paradigm

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 07/05/2009

RickM — Mon, 06 Jul 2009 01:11:00 GMT

If you find yourself in the Boston area tomorrow, Monday July 6th, come see Amanda Laucher’s New England F# User’s Group talk. She is currently working on a new book for O’Reilly: F# in a Nutshell.

Luca Bolognese’s Series on LAgent: Parts One, Two, Three, Four, Five and Six

I built myself a little agent framework based on F# MailboxProcessors. I could have used MailboxProcessors directly, but they are too flexible for my goal. Even to write a simple one of these guys, you need to use async and recursion in a specific pattern […]

Each article is a worthwhile read, containing at least one tasty morsel of F# information. For example, I'm sure to use the dynamic function loading from part six sometime in the near future.

Slides for Robert Pickering’s Tech Days Paris Talk: Introduction to F# and Collective Intelligence

Hello. I’m F#. Friendly, Approachable. Built in .NET.

I enjoyed the quotes from Don Syme, Eric Meijer, and Julien Laugel. The collective intelligence example was also very well demonstrated. Most of all, I enjoyed having a chance to see how Robert Pickering puts together a F# presentation. I particularly like his style of annotating functions.

Oliver' Strum’s Channel 9 Talk on F# – Taking Efficiency One Step Further

Microsoft Research describes F# as "a scripted / functional / imperative / object-oriented programming language". Combining all those aspects in one language is certainly not an easy task, but they've done a good job of it.

In this talk, Oliver covers the basics well. He also does a very good job at conveying why the functional programming constructs in F# are so important.

Matthew Podwysocki’s F# - Async Running with Continuation Scissors

[…] let’s walk through a simple example of using the Twitter HTTP API to get a user timeline using F# asynchronous workflows.

A fast ride through the basics of using the twitter HTTP API in F#. I hadn’t previously seen an example of Async.RunWithContinuations. This error handling style is quite elegant.