Say I've to develop an app that runs on iOS, Android and Windows 8 Mobile. Now all three platforms are technically in different program languages. The only 'reuse' that I can see is that of the boxes-and-lines drawings (UML :) charts and nothing else.

So how do companies/programmers manage the variation of the same product across different platforms especially since the implementation languages differ? It's 'easier' in the desktop world IMO given the plethora of languages and cross-platform libraries to make your life easier. Not so in the mobile world.

More so, product line management principles don't seem to be all that applicable - what is same and variant doesn't really matter - the application is the same (conceptually) and the implementation is variant.

Some difficulties that come to mind:

• Bug Fixing: Applications maybe designed in a similar manner but the bug identification and fixing would be radically different. A bug on iOS may/may-not be existent for that on Android. Or a bug fix approach on one platform may not be the same on another (unless it's a semantic bug like a!=b instead of a==b which would require the same 'approach' to fixing in essence
• Enhancements: Making a change on one platform would be radically different than on another
• Code-Design Divergence: They way the code is written/organized, the class structures etc., could be very different given the different implementation environments - leading to further reuse of the (above) UML models.

There are of course many others - just keeping the development in sync and making sure all applications are up to the same version with the same set of features etc. Seems the effort is 3x that of a single application. So how exactly does one manage this nightmarish situation?

Some thoughts:

• Split application to client/server to minimize the effect to client side only (not always doable)
• Use frameworks like Unity-3D that could take care of the cross-platform problem (mostly applicable to games and probably not to other applications etc.)

Any other ways of managing a platform line? What are some proven approaches to managing/taming the effects?