Phillip Trelford's Array

Last week I travelled to Malmö in Sweden for Øredev, a large well established annual conference primarily covering enterprise development practices from programming to agile.

The first night at the event was probably the most surreal I’ve experienced at a developer conference. It began with a keynote from XKCD creator Randall Munroe covering their increasingly elaborate April fools’ day pranks and turning his lounge into a ball pit.

Then, along with Rachel Reese, Julie Lerman, Iris Classon and some enthusiastic locals, I found myself in a boxing ring at the hotel watching an impressive impromptu display of acroyoga and slacklining.

The night continued on in to the early hours hacking F# with Iris, which attracted a small crowd of interested onlookers. Iris picked up F# really quickly and by the end of the night she had put together a great solution to a Kaggle machine learning competition task, while still finding time to squeeze in some tango dancing.

In the morning I woke to the entire room shaking, to the point that I thought the TV was going to come off the wall, later I learnt I was sleeping below the running machines in the gym.

Just about everyone at the conference was staying in the same hotel, just around the corner from the venue, which made it a very fun social event. It was really nice to catch up with Ashic Mahtab, Torbjörn Gyllebring and Paul Stack, and finally meet in person Jessica Kerr, Bodil Stokke, Richard and Carl from .Net Rocks, Shay Friedman and Steve Klabnik, to name just a few.

It was Rikard Ottosson who kindly invited me to give two talks at the conference, first F# Eye for the C# Guy and then F# for Trading. All the sessions were recorded and most are already available online. For some more functional love I’d highly recommend watching Rachel Reese, Bodil Stokke and Jessica Kerr’s talks.

F# Eye for the C# Guy

I first presented this talk at DDD Belfast back in 2011, and somehow it got a mention on Microsoft’s Channel 9! Since then it’s taken me to Seattle, San Francisco, Cambridge (twice), London, Norwich, Sunderland and now Malmö. Each one is slightly different but the overall theme has remained constant.

The title was borrowed from a presentation by Leon Bambrick made in 2008, and the F# logo complete with unicorn is courtesy of Chris Smith who is also responsible for the faux art work on the Learning F# 1.0 book. The not entirely genuine F# 3.0 in Action cover is all my own doing.

In the live demos I take an immutable C# class and transform it into equivalent F#, to show some of the syntactic differences. Then the focus turns to unit testing with NUnit, FsUnit, Unquote and Foq, followed by automated acceptance testing with TickSpec.

From there the focus switched to Type Providers including FSharp.Data’s JSON provider. Then accessing data from the World Bank and presenting it in a web page with High Charts using Tomas Petricek’s FunScript sample.

It was great to get a lot of questions at the end:

and some really encouraging feedback on Twitter:

The F in F# stands for fun. It's actually a keyword." - @ptrelford :) #oredev

Best talk so far F# for C# developers! Thanks @ptrelford #oredev

F# for Trading

After seeing a video of Rich Hickey’s Simple made Easy talk at Stangeloop back in 2011, I really wanted to make it to the next event, and submitted F# for Trading. I was both hugely grateful and a little surprised that it was accepted and was able to attend what is a fantastic alternative conference. Since then I’ve presented variants in San Francisco, New York, London and Amsterdam.

Thanks again to Torbjörn for the nice quotes he put up on Twitter during the session:

When you look at a language you will also get a community, with a special feel and specialization. ~ @ptrelford #oredev

Non programmers learn F# easily. Those with OOP background need to spend time un-learning first. ~ @ptrelford #oredev

The real performance gains are found by having time finding better algorithms. F# frees time up for that. ~ @ptrelford #oredev

Immutability and strong typing let's me relax and be confident things will work ~ @ptrelford #oredev ergonomics matter.

Yes, @ptrelford did just intellisense his way through open World Bank data. That's what F# type providers enables. #oredev

And to Rikard for inviting me over and to the whole Øredev team for putting on a fantastic event.

The fun continues over the coming weeks, next up I’ll be at:

• DDD Dundee (Scotland) Nov 23
• F# in Finance (Microsoft London) Nov 25
• Developer South Coast (Southampton) Nov 26
• CodeMesh (Central London) Dec 3-5
• NDC London (Docklands) Dec 2-6

Last week’s Progressive F# tutorials conference seems to have struck a note:

Progressive F# 2013 best conference ever. Fact. #progfsharp

A big thanks to Skills Matter for organizing this 2-day hands on community event:

You can see pictures from the event on Skills Matter’s Facebook photo stream:

Following on from events in 2011 and 2012 this year we welcomed 79 F#ers:

#progFsharp seems to grow in size every year :)

If you’d like to join us next year there’s currently an early bird discount:

If you enjoyed #progfsharp this year, why not get in early & get your ticket for next year? Tickets just £95 http://ow.ly/qoV5Y

This year’s F# Tutorials ran over 2 days with 2 tracks of hands on sessions.

Day 1

Jon Harrop kicked off proceedings with a talk on using F# to change the way we work:

Followed by an F# Koans session with Rachel Reese, Dan Mohl and Robert Pickering. The F# Koans are a great way to get started with F#.

At the same time we ran a Programming with the Stars session with Rich Minerich and volunteer Michael Newton. This year‘s task was the Bank OCR Kata:

 1: let zeroToNineText = """
 2:  _     _  _     _  _  _  _  _ 
 3: | |  | _| _||_||_ |_   ||_||_|
 4: |_|  ||_  _|  | _||_|  ||_| _|                          
 5: """
 6: 
 7: let getDigits (source:string) len =
 8:     let lines = source.Split([|'\n'|]).[1..3]
 9:     [for digit in 0..len-1 ->
10:         let index = digit*3
11:         [for line in lines -> line.[index..index+2]]
12:     ]
13: 
14: let zeroToNine = getDigits zeroToNineText 10
15: 
16: let toNumber text =
17:     getDigits text 9
18:     |> List.fold (fun acc digit ->
19:         let n = zeroToNine |> List.findIndex ((=) digit)
20:         acc * 10 + n
21:     ) 0
22:         
23: let accountText = """
24:     _  _  _  _  _  _     _ 
25: |_||_|| || ||_   |  |  ||_ 
26:   | _||_||_||_|  |  |  | _| 
27: """
28: 
29: let n = toNumber accountText

The code above was my attempt, check out more solutions on F# Snippets:

• Official SkillsMatter 2013 F# Tutorials Programming with the Stars Code Snippet
• Zach Bray’s solution
• Daniel Kovi’s solution
• Shortest solution

In the afternoon Rachel Reese ran a hands on session on Try F# from Zero to Data Science:

Looks like we broke http://tryfsharp.org during @rachelreese great workshop session ;) #progfsharp

Thought - @rachelreese should rename her session to DOSing around on TryFSharp ;) #progfsharp :D

Meanwhile Robert Pickering’s tutorial was on programmatically generating sounds and music with Undertone.

Playing with Undertone with @alanmgreen and @DaveHoganIW at #progfsharp... did I mention I know nothing about music! :> /cc: @robertpi

After some pizza and drinks, the coding spilt over to the local pub:

And by all accounts the fun continued on through the night:

Day 2

In the morning there was a choice between Machine Learning for Fun and Profit with Matt Moloney and Time for Functions in the Enterprise with Simon Cousins (which was my 11yo son’s favourite session!).

In the Machine Learning session we used Deep Belief Networks to categorize digits and to predict fluctuations on the Bitcoin/USD exchange rate.

The code sample and tasks are here: http://trelford.com/ProgFSharpML.zip

Simon’s slides and samples are here: https://github.com/simontcousins/pft2013

In the afternoon Dan Mohl and Zach Bray led a tutorial on Web Programming while Rich Minerich ran a Pacman AI competition.

Dan and Zach’s slides and tasks: https://github.com/dmohl/FsOnTheWeb-Workshop

Here’s a screenshot from the Pacman session:

Ben Lynch won the competition with a really strong AI:

Probably the best #fsharp conference in the world #progfsharp - and not just 'cos I won the graphman contest! (which I did, by the by ...)

If you fancy having a go at writing your own Pacman AI, pop down to the F#unctional Londoners meetup on November 14th.

I’m already looking forward to next year, if you can’t wait that long for some more conference action with F# check out:

• F# in Finance at Microsoft London on Nov 25
• CodeMesh in London on Dec 3-5
• NDC London on Dec 2-6

.Net was Microsoft’s answer to Java. Java promised a single language that could target multiple platforms. .Net offered multiple languages that targeted Windows. Back then that meant C#, VB.Net and C++/CLI,

Virtual Machines

Things have moved on for both VMs, the JVM now has a plethora of languages like Groovy, Clojure and Scala. Meanwhile .Net code has become cross platform via Mono, in fact C# and F# now have arguably offer a better story for iOS than Java. For iOS, Xamarin compiles C# and F# code to native ARM binaries.

Both VMs have been hugely successful and have seen a wealth of libraries and frameworks built on them, allowing them to interoperate with a vast array of software and devices. This makes languages built on these VMs compelling as you don’t need throw away existing enterprise investments and build everything again from scratch.

Java 8

Progress on the Java programming language has been slow, which has in part helped accelerate the adoption of new functional-first languages like Clojure and Scala. Java will be the last mainstream programming language to add lambdas when Java 8 is released potentially in March 2014.

Question marks have also been hanging over Java’s open source credentials since Oracle’s acquisition of Sun. Back in March 2012, Thoughtworks put the Future of Java in the Assess ring of their Technology Radar.

That said in London at least the Java community seems to be strong in numbers with over 3,500 members in the LJC meetup compared to just over 400 for the London .Net meetup.

C# Convergence

C#, VB.Net and C++/CLI all share similar features and so the vast majority of developers have converged over time on the C# programming language.

The dynamic CLR languages IronPython and IronRuby have lost much of their momentum and Nemerle seems to have been subsumed by JetBrains for N2.

That really just leaves F# under active development, built-in to both Visual Studio and Xamarin Studio, it uses the same compiler as F# is open source under Apache 2.0.

C# 5

On .Net, the C# programming language has seen a little more innovation than Java, adding rudimentary functional programming constructs in C# 3 for LINQ like lambdas and extension methods for expressing higher-order functions.

Progress in C# 4 and 5 has been lacklustre since Microsoft departed on a rewrite of the compiler in C#, a closed source project called Rosyln, which is yet to surface.

In C# 4 the focus was on dynamic support, where the main new feature in C# 5 was async, a feature introduced in F# in 2007.

Linux

In the enterprise one of the biggest threats to .Net code bases is migration to Linux, for which outside of Mono there is no .Net story. Xamarin, key contributors to Mono, are overwhelmingly focused on mobile. Recent improvements in Mono, particularly in garbage collection, I feel make it a viable server-side platform, but it currently lacks the support and investment seen on the JVM.

As large enterprises continue to look for cost savings, I suspect more .Net share could be lost to switches to Linux. Lower operating costs combined with the promise of higher productivity with powerful functional-first languages like Clojure and Scala, are hard for IT managers to ignore. Nowadays many finance companies use the JVM on the server-side and reserve .Net, specifically WPF, solely for their front-end applications.

I’d like to see Microsoft join forces with Xamarin to deliver a well supported server-side platform with Mono for C# and F# on Linux, to compete directly with Clojure and Scala. That also means .Net open source authors should be supporting Mono deployments too.

Polyglot Programming

The promise of polyglot programming on .Net, where you pick appropriate languages for specific tasks, now rests primarily with familiar C# and functional-first F#.

As C# and F# are statically typed languages on .Net, interop between them is seamless. Both languages also offer bridges to external libraries via C APIs with P/Invoke. F# also offers rich interop to data sources and programming languages on other platforms via Type Providers.

With F# Type Providers you can interact with languages like R, MATLAB and TypeScript and their rich libraries with intellisense support in your editor. Type Providers are a real enabler for true polyglot programming.

Edge.js also bridges the gap between the .Net and JavaScript worlds with Node.js interop.

The combination of C# with it’s familiar syntax and object-oriented constructs with F# and it’s functional-first constructs and type providers, in my opinion, offers arguably the most powerful and productive programming environment currently available.

In the same Thoughtworks Technlogy Radar that questions the Future of Java, they had this to say on F# and C#:

F# is excellent at concisely expressing business and domain logic. Developers trying to achieve explicit business logic within an application
may opt to express their domain in F# with the majority of plumbing code in C#.

I’m seeing more and more .Net shops adopt F# alongside C#, take for example Kaggle a data science consultancy based in San Francisco:

At Kaggle we initially chose F# for our core data analysis algorithms because of its expressiveness. We’ve been so happy with the choice that we’ve found ourselves moving more and more of our application out of C# and into F#. The F# code is consistently shorter, easier to read, easier to refactor, and, because of the strong typing, contains far fewer bugs.

As our data analysis tools have developed, we’ve seen domain-specific constructs emerge very naturally; as our codebase gets larger, we become more productive.

The fact that F# targets the CLR was also critical - even though we have a large existing code base in C#, getting started with F# was an easy decision because we knew we could use new modules right away.

The point here is not to throw the baby out with the bath water and rewrite your entire solution in a new language, instead leverage your existing investments and use the right tool for the job on new features.

Functional Programming

Functional programming has permeated the majority of mainstream programming languages, and is gaining increasing mind share. Here’s a nice slide from Grant Crafton’s recent session on functional programming at DDD North:

It’s clear to me that many of the original protagonists of object-oriented programming are migrating towards functional. Recently I met Eric Evans, author of Domain Driven Design, in New York who spoke at length on how he’d gone all-in on functional.

At conferences like Strangeloop, I’d go as far as saying this is a done deal, very few people are talking about OOP anymore.

Functional Learning

There’s been quite a lot of FUD around functional programming being hard to learn. In general people encounter two initial speed bumps:

• Unfamiliar syntax
• Unlearning 

Neither of these speed bumps are insurmountable, otherwise there wouldn’t be such a large number of developers turning to functional languages.

Lack of familiarity with syntax can be overcome with just a few hours of immersion. For F# I’d recommend the F# Koans to guide you through the language syntax step-by-step and a Cheat Sheet to lookup common operations as you code. F#’s syntax is based on the ML programming language, once you’ve got the hang of it you’ll be able to read a host of other ML based languages like Erlang and Haskell.

Unlearning tends to take longer than learning, so unfortunately if you’ve been programming in an imperative or object-oriented style for a long time, it will be slightly harder to pick up functional programming. That it to say learning functional programming is not inherently hard, just that thinking differently can take some time. I’d recommend tackling short programming exercises like Code Katas or Project Euler problems to break the back of it.

Be patient, once you’re over the hump you could find the experience fun and rewarding:

#fsharp has really grabbed my attention. Not been this excited about a new language for a while.

— Mark Robinson (@Defstun) October 16, 2013

Happy learning!