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Starting with templates, Android features can be added quickly with a single line of DSL code.

In the first installment of this two-part series on developing Android Apps with Scala and Scaloid, I explained how Scaloid simplifies and reduces the required Android code as much as possible while leveraging type safety. In this article, I explain how to utilize asynchronous task processing, the execution of methods from system services, and specific Scaloid classes and traits.

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The theory and practicum of type inference has been around for literally decades, but it remains a tricky and needlessly dry topic, even in academic circles. This talk will delve into the glorious details and subtle implications of type inference in industrial languages like C# and Scala, as well as highly mathematical languages like Haskell. We will uncover the sordid reasons beyond some of the many unnerving quirks of modern type inference schemes, as well as the the amazing power they proffer.

Love of math is not a prerequisite, though utter dread of such may result in minor hallucinations during the talk. Deep-seated hatred of static typing is welcomed! The primary focus of this talk will be on Scala, Haskell and SML, but prior knowledge of these languages is neither expected nor required.

Direct download: Uncovering_the_Unknown_-_Principles_of_Type_Inference.mp4
Category:ETE 2011
-- posted at: 11:36 PM

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This years FOTB was special. At the end of my session I showed a sneak preview of project Hiddenwood. I demonstrated complete playback of Audiotool tracks on stage — in a browser. Now that does not sound too special…

But then again, the playback was done using JavaScript only and calculated in realtime.

Audiotool is a complex piece of software so you might ask how one could torture themselves by implementing it in JavaScript? We didn’t. Instead we started building our own vision of a cross-platform application framework a couple of months ago.

Introducing project Hiddenwood.

Hiddenwood is a collection of libraries and tools specifically designed to support different devices and platforms. The core libraries are the “driver layer” and always platform-specific with a platform-independent interface.
On top of that we provide a basic layer of libraries like our UI system, animation framework or managed collections which guarantee 0% garbage collection activity and have been battle-tested in Audiotool.

The framework is all about speed and consistency. The rendering pipeline is optimized for OpenGL and although we offer something similar to Flash’s display list a lot of features are not available because they would compromise the speed.

Speaking about speed: we are always interested in staying as native as possible on our target platform. So for the browser we emit JavaScript, for Android you will get the full DalvikVM performance and for the desktop you will get JVM performance. This approach has also another very important aspect. If you want to go platform-specific for certain features you can do that.
For instance if we want to render Audiotool songs on the server using a fork-join pool for our audio calculation this is possible and might not make sense on an Android device.

You write Java code and the supported platforms are native desktop applications, Android (minimum requirements are Gingerbread and OpenGL ES 2.0) and modern browsers. Now for browsers we even go one step further and support multiple options. That means if WebGL is not available we simply fallback to a normal canvas based render-engine. The same applies to some of the Android drivers.

iOS is of course important as well and we are actively researching the best option that will give us the most flexibility and performance.

We are currently working on two real applications built with Hiddenwood. So far it is a real pleasure to enjoy quick build times and simply test what you want on the desktop with great debugging capabilities. When you are ready you can try the same app on Android or in the browser — which might take a little bit longer to compile.

Because we see Hiddenwood as an application framework there are a lot of goodies built-in like a sprite-sheet based class generator. Think Image mixerBackground = Textures.mixer.background(); where mixer was the folder name and background the name of the file.

We believe that as a developer you really do not care about what kind of technology you are using and just want a great result. We also think that you should be able to reuse platform-independent code across multiple projects. However we do not want to take power away from the developer because if you know what you are doing: go for it.

Of course we are not the only ones with this idea. Nicolas Cannasse saw the signs years ago and invented haXe which gives you a comparable experience and Google released playN a couple of weeks ago which takes a similar approach (and requires another 25 committers :P).

But when we started Hiddenwood we wanted the Java tooling experience and playN was not public at that time. We also think that a game engine is not what you want to use for all kinds of applications. So we like to be able to give people the freedom to build their own game engine on top of Hiddenwood — and calculate physics in a different thread peut-être.
Speaking about threading: the only possible solution that works across all platforms is a shared-nothing architecture which we put in place. However if you write platform specific code you can use of course everything the platform offers and a lot of the Hiddenwood core libraries like the network- or cache-layer make use of multiple threads.

In the end what makes Hiddenwood special in my opinion is that we do not believe in write once run anywhere because that just does not make sense. The essence and philosophy behind Hiddenwood is to write platform-agnostic code using kickass-libraries and being able to reuse that. Audiotool on a tablet would look completely different from Audiotool running in a browser. And Audiotool on iOS would probably be also a little bit different from Audiotool on an Android device because there are simply different paradigms you should respect.

I hope that we can share more information with you soon. With the news of mobile Flash Player being deprecated and the ongoing demand for cross-platform development we have exciting times ahead of us. I am also super excited about the (beautiful <3) applications which we are going to release in the not so distant future.

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