I have been talking to Rhomobile about their new cross platform Ruby-based mobile application framework. Rhomobile is different in that it’s open source. As I will explain later in this post, being open source solves some problems associated with mobile cross platform frameworks.
I tend to assess cross platform frameworks (and widget frameworks) against the following criteria…
- Cross platform – How many platforms are supported?
- Functionality – What phone features are supported?
- License – How costly is it to use for commercial and hobby applications?
- Extensibility – What about access to phone features not supported by the framework?
- Look and feel – Do the completed applications have the look and feel of native applications on the phone?
- Legality – adherence to the iPhone SDK agreement (sec 3.3.2) not allowing calls into frameworks
So how does Rhomobile fare? Rhomobile currently has implementations for the iPhone, Windows Mobile and Blackberry. The Symbian version should become available at about the same time as the Symbian Partner Event next month. Android and LiMo versions has been mentioned.
Currently, Rhomobile just has geolocation (both as an "extended HTML tag" and a Ruby call). By January it should have camera, accelerometer, video, and PIM access. Beyond this, additional phone features are something currently being worked out – that’s one reason why they contacted me – for ideas.
Licensing is free if you open source your code. If you don’t open source then you will need a commercial license. I have been told that Rhomobile are committed to being very aggressive on pricing. At the moment, the model is 5%, whether its upfront license fees or per app shipped. If you’re selling freeware then Rhomobile will work out some reasonable deal. Basically, they are currently very open to any proposals and are initially very open to deals (but not quite free) to get the framework out there.
In terms of extensibility the thinking is that this be done by creating extended Ruby calls in a library. The great advantage of open source is that this should be easy enough for developers to do for themselves.
For ‘look and feel’ they are attempting to get pretty close to the native look and feel. For example, the iPhone version uses IUI. Similar things occur on Windows Mobile and RIM (but haven’t been checked into open source yet).
I have been told that the legality aspect of running Ruby on the iPhone is covered by "compiling it in". i.e. the completed application just does what the developer declares at compile time so there’s no extra functionality possible by running scripts. This also means there’s no separate runtime to install.
I particularly like the open source aspect because some people are now afraid of committing commercial projects to 3rd party runtimes when it’s not known how long the runtime will be around (e.g. People previously using AppForge were left without a runtime). I am not saying Rhomobile will go under – it’s just another thing to be considered. In terms of viability, I have been told that Rhomobile’s backers are committed to funding the company with little revenue expectations for years.
Rhomobile is still under development. It has lots of potential. In fact, the first company that can crack the problems of functionality, license, extensibility and ‘look and feel’ will have a something truly useful and might even revolutionise mobile application development.