Phillip Trelford's Array

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Flappy

2. July 2015 F#, Mono, .Net, WPF Comment (1)

This week I ran a half-day hands on games development session at the Progressive .Net Tutorials hosted by Skills Matter in London. I believe this was the last conference to be held in Goswell Road before the big move to an exciting new venue.

My session was on mobile games development with F# as the implementation language:


Here’s a quick peek inside the room:


The session tasks were around 2 themes:

  • implement a times table question and answer game (think Nintendo’s Brain Training game)
  • extended a simple Flappy Bird clone

Times table game

The motivation behind this example was to help people:

  • build a simple game loop
  • pick up some basic F# skills

The first tasks , like asking a multiplication question, could be built using F#’s REPL (F# Interactive) and later tasks that took user input required running as a console application.

Here’s some of the great solutions that were posted up to F# Snippets:

To run them, create a new F# Console Application project in Xamarin Studio or Visual Studio and paste in the code (use the Raw view in F# Snippets to copy the code).

Dominic Finn’s source code includes some fun ASCII art too:

// _____ _   _ _____ _____ _____  ______  _  _   _____  _____ _     
//|  __ \ | | |  ___/  ___/  ___| |  ___|| || |_|  _  ||  _  | |    
//| |  \/ | | | |__ \ `--.\ `--.  | |_ |_  __  _| | | || | | | |    
//| | __| | | |  __| `--. \`--. \ |  _| _| || |_| | | || | | | |    
//| |_\ \ |_| | |___/\__/ /\__/ / | |  |_  __  _\ \_/ /\ \_/ / |____
// \____/\___/\____/\____/\____/  \_|    |_||_|  \___/  \___/\_____/
//

Flappy Bird clone

For this example I sketched out a flappy bird clone using Monogame (along with WinForms and WPF for comparison) with the idea that people could enhance and extend the game:

image

Monogame lets you target multiple platforms including iOS and Android along with Mac, Linux, Windows and even Rapsberry Pi!

The different flavours are available on F# Snippets, simply cut and paste them into an F# script file to run them:

All the samples and tasks are also available in a zip: http://trelford.com/ProgNet15.zip

Have fun!

NDC Oslo 2015 Experience Report

21. June 2015 F#, Erlang Comment (0)

Last week my son Sean and I popped over to Norway for NDC Oslo, billed as one of the world’s largest independent software conferences.

Venue

The venue, the Oslo Spektrum in the centre of the city was huge, with a large lower floor for vendors and refreshments surrounded by 9 rooms for talks. There were nearly 2000 delegates and nearly 200 speakers at the event, enjoying a veritable binge festival of hour long talks, and even a room where you could watch all the talks simultaneously on a series of big screens.

Invitation

My 8yo Sean had been invited to do a lightning talk, and according to one NDC conference organizer they were then stuck with inviting me along too, apparently something they wouldn’t have done otherwise, or so he felt compelled to tell me on our first meeting. The other organizers seemed happier to see me or perhaps were more able to exercise tact. Regardless, it was great to meet up with many friends old and new and from far and wide.


Travel

NDC were kind enough to arrange flights and accommodation for me, but I had to pay for Sean’s travel myself. The hotel was close to the venue, unfortunately when we arrived late on Wednesday night it was over-booked and the room we were initially sent to was already occupied, where the phrase what is seen cannot be unseen is probably quite fitting. Thankfully we were eventually rehoused in another hotel nearby. The next day we were asked to pay 4500Kr (450GBP) to remain in the hotel. After some assistance from organizer Charlotte Lyng we were relieved to be given an unoccupied room at the original hotel for the following nights.

Lightning talk

Sean’s lightning talk was after lunch on the Thursday, the room was standing room only with over 100 attending, and he had a great reception. He started with a short rendition of Pink Floyd’s Wish You Were Here while I set up the laptop (thanks to Carl Franklin of .Net Rocks for the loan of the guitar). Followed by the main content, a live coding session on Composing 3D Objects in OpenGL with F#.

There was a lot of reaction on Twitter, here's a few of the many tweets:






Thanks for all the supportive comments, this was only Sean's third public speaking engagement and he really enjoyed speaking at and attending the conference.

You can try composing your own 3D scenes in the browser with F# and WebGL at Fun3D.net


F# for C# developers

My talk was an introduction to the F# programming language from a C# developer's perspective and also seemed to be well received, although in terms of Twitter I was rightly eclipsed by my son Sean's efforts. In fact from now on I think I might be more commonly known as Sean's dad.



I also appear to have made the NDC Oslo speaker leaderboard, in the 100-200 audience category, thanks for all the greens votes! :)


Other talks

We saw some fantastic talks including Phil Nash on his C++ unit testing framework Catch, Gojko Azdic's thoughts on Continuous Delivery, Grey Young's new project PrivateEye, Tomas Petricek's live coded F# web programming session, Gary Short's Troll Hunting talk and many more. It was also great to see F# feature so heavily both on and off the functional programming track, and attendance on the FP track doubling since last year!

Summary

Both Sean and I really enjoyed the conference, there were a vast array of speakers to learn from, huge numbers of passionate developers to mingle with during the breaks and a very child friendly vendor floor. The floor was complete with a surfboard simulator, and Sean was very happy to win a Raspberry Pi for his efforts on it, along with enjoying an endless supply of ice cream! Also, look out for Sean's interview on Herding Code which should be out in a month or so.

Legacy Hiring

17. June 2015 Comment (2)

Over the years I’ve been involved in a lot of developer hiring. Here I’d like to share a pearl of wisdom I gleaned from a colleague I shared the hiring process with.

Their angle was to give extra points to people with experience with both building AND maintaining systems, i.e those who stuck around long enough to understand the consequences of their own actions.

I found this is an interesting insight, the logic being that you learn the longer term impact of your design decisions from hanging around to fix the faults and add new features.

But what does staying the distance actually teach you? I think the only real way is to find out for yourself, but here’s a few things that spring to mind.

Prefer simple

Simple isn’t easy, there’s an old saying that goes “I didn't have time to write a short letter, so I wrote a long one instead”.

The same goes for code; finding the underlying simplicity can take significantly longer than just bashing out the first thing that comes to mind. However the long term payoffs for system maintenance can be huge.

Tests

Tests can be a good thing, and test-driven development (TDD) can provide a helpful suite of regression tests to move forward with. However if the end result is tightly-coupled tests then the the pattern might be better coined Test-Driven Concrete (TDC), as instead of making change easier the product becomes almost impossible to maintain (thanks to Ian Johnson for the metaphor).

Instead of testing at the class and method level you should be testing required behaviour.

Summary

If you’re embarking on a big shiny new project, it might make sense to have some developers around who’ve been through the mill and come out the other side, and can help guide you to a more maintainable future.

Do you have any tips to share?

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