Phillip Trelford's Array

Are you working in the enterprise?

Do you find yourself, day-in-day-out, up to the eyeballs in unmaintainable code?

Does the once beautiful architecture now more closely resemble a big ball of mud, that no amount of tooling will dig you out of?

What can you do?

1) Bury your head in the sand

A very popular option, you just need to keep practising denial.

2) Turn to drink

Another popular option, although unfortunately this strategy is only likely to last as long as your liver.

3) Become a scrum master

This is an easy way out, scrum certification is just a 2 day course away, but there’s probably no looking back.

4) Admit there’s a problem

This is one of the hardest and least popular options, but possibly the most rewarding.

Start by saying out loud: “Object Oriented Programming is an expensive disaster which must end” and then take each new day as it comes.

In a recent thread on CodePlex Mads Torgeson, C# Language PM at Microsoft, announced 2 of the key features planned for C# 6 release have now been cut:

• Primary constructors
• Declaration expressions

According to Mads:

They are both characterized by having large amounts of downstream work still remaining.

primary constructors could grow up to become a full-blown record feature

Reading between the lines Mads seems to be saying the features weren’t finished and even if they were they seemed to conflict with a potential record feature currently being prototyped.

The full thread is here: Changes to the language feature set

Language Design

I think there’s two distinct options when adding new features to an existing language with a large user base:

• upfront design
• implement incrementally

Upfront design should mean that all cases are met but comes at a time-to-market cost, where as an incremental implementation means quick releases with the potential risk of either sub-optimal syntax or backward compatibility issues when applying more features.

It appeared at the high level that the C# team’s had initially opted for the incremental option. The feature cuts however suggest to me that there may have been a change in direction towards more upfront design.

Primary Constructors

The primary constructors feature was intended to reduce the verbosity of C#’s class declaration syntax. The new feature appeared to be inspired by F# ’s class syntax.

If you like the idea of a lighter syntax for class declarations then you may just want to try F# which already has a well thought out mature implementation, i.e.

type Person(name:string, age:int) =
    member this.Name = name
    member this.Age = age

Or for simple types use the even simpler record type:

type Person = { Name:string, Age:int }

Note: on top of lighter class syntax F# also packs a whole raft of cool features not available in C#, including powerful pattern matching and data access via Type Providers.

Declaration Expressions

Declaration expressions was again designed to reduce verbosity in C# providing a lighter syntax for handling out parameters. Out parameters are used in C# to allow a method to return multiple values:

int result;
bool success = Int32.TryParse("123", out result);

Again handling multiple return values is handled elegantly in F# which employs first-class tuples, i.e.

let success, value = Int32.TryParse("123")

As shown above, C# out parameters can be simply captured in F# as if the method were returning multiple values as a tuple.

Conclusion

The first time I saw Mads publicly announce the now cut primary constructor syntax and declaration expressions was nearly a year ago at NDC London. At the time the features were announced with a number of disclaimers that they may not actually ship. I think in future it may be better for everyone to take those disclaimers with more than just a pinch of salt.

This Saturday saw the Developer Developer Developer! (DDD) East Anglia conference in Cambridge. DDD events are organized by the community for the community with the agenda for the day set through voting.

T-Shirts

The event marked a bit of a personal milestone for me, finally completing a set of DDD regional speaker T-Shirts, with a nice distinctive green for my local region. Way back in 2010 I chanced a first appearance at a DDD event with a short grok talk on BDD in the lunch break at DDD Reading. Since then I’ve had the pleasure of visiting and speaking in Glasgow, Belfast, Sunderland, Dundee and Bristol.

Talks

There were five F# related talks on the day, enough to fill an entire track:

• Taking your craft seriously with F# - Tomas Petricek
• Functional DDD - Alessandro Melchiori
• Building Skynet: ML for developers - Anthony Brown
• Using F# for Line of Business Apps – Ian Russell
• All your types are belong to us!

Tomas kicked off the day, knocking up a simple e-mail validation library with tests using FsUnit and FsCheck. With the help of Project Scaffold, by the end of the presentation he’d generated a Nuget package, continuous build with Travis and Fake and HTML documentation using FSharp.Formatting.

Anthony’s SkyNet slides are already available on SlideShare:

ASP.Net was also a popular topic with a variety of talks including:

• OWIN, Katana and ASP.NET vNext 
• Decoupling from ASP.NET - Hexagonal Architectures
• The vNext Big Thing

All your types are belong to us!

The title for this talk was borrowed from a slide in a talk given by Ross McKinlay which references the internet meme All your base are belong to us.

You can see a video of an earlier incarnation of the talk, which I presented at NorDevCon over on InfoQ, where they managed to capture me teapotting:

The talk demonstrates accessing a wide variety of data sources using F#’s powerful Type Provider mechanism.

The World at your fingertips

The FSharp.Data library, run by Tomas Petricek and Gustavo Guerra, provides a wide range of type providers giving typed data access to standards like CSV, JSON, XML, through to large data sources Freebase and the World Bank.

With a little help from FSharp.Charting and a simple custom operator based DSL it’s possible to view interesting statistics from the World Bank data with just a few key strokes:

[uk;fr;de] => fun country -> country.``CO2 emissions (metric tons per capita)`` // FSharp.Data + FSharp.Charting pic.twitter.com/D65m2KmZGp

— dirty coder (@ptrelford) September 11, 2014

The JSON and XML providers give easy typed access to most internet data, and there’s even a branch of FSharp.Data with an HTML type provider providing access to embedded tables.

Enterprise

The SQLProvider project provides type access with LINQ support to a wide variety of databases including MS SQL Server, PostgreSQL, Oracle, MySQL, ODBC and MS Access.

FSharp.Management gives typed access to the file system, registry, WMI and Powershell.

Orchestration

The R Type Provider lets you access and orchestrate R packages inside F#.

With FCell you can easily access F# functions from Excel and Excel ranges from F#, either from Visual Studio or embedded in Excel itself.

The Hadoop provider allows typed access to data available on Hive instances.

There’s also type providers for MATLAB, Java and TypeScript.

Fun

Type Providers can also be fun, I’ve particularly enjoyed Ross’s Choose Your Own Adventure provider and more recently 2048:

Write your own Type Provider

With Project Scaffold it’s easier than ever to write and publish your own FSharp type provider. I’d recommend starting with Michael Newton’s Type Provider’s from the Ground Up article and video of his session at Skills Matter.

You can learn more from Michael and others at the Progressive F# Tutorials in London this November:

DDD North

The next DDD event is in Leeds on Saturday October 18th, where I’ll be talking about how to Write your own Compiler, hope to see you there :)