Go version 1.5 is on the way later this summer. One of the more interesting features is the ability to cross-build apps for Android and iOS. Is this just an experiment for Google or do they have bigger plans?

Go has been making waves in backend development for a few years now. With syntax inspired by Python and a latent desire to correct the mistakes of C++ and Java, Go is certainly unique. For those who haven’t tried it, it has some excellent concurrency and packaging features that make it enjoyable to use. While it hasn’t yet reached performance parity with C++ or the 3rd-party package support levels of Python, it has been growing rapidly.

On the eve of Go’s upcoming release, Google quietly published a calculator app called Ivy to the App Store and Google Play. We took a look under the hood to see how they built an Android & iOS app using Go.

There’s a useful series of articles by Keith Lea on the basics. For Ivy, it has a minimal app delegate (iOS) and main activity (Android), which wrap the main Go runtime and calculator code. There are no SDKs, nor much use of any platform-specific features like UIKit. The display is just a drawing area, like an HTML5 canvas. David Crawshaw, one of the developers, just gave some more background on HN.

As a nod to the App Store restrictions, Google disabled the get "FILE" command in the Ivy interpreter. The app also uses minimal Go mobile features (just the bind interface). It appears they just wanted to test the app store release processes or commemorate this milestone.

The major remaining question is, “what is Google going to do about cross-platform support?” There are a number of cross-platform toolkits that we track at SourceDNA, and runtime is just the starting place. Developers need well-designed libraries that give them access to GUI and platform capabilities. In a recent discussion, Google engineer Brad Fitzpatrick said that they are not working on this problem.

Unless a third-party fills this vacuum, Golang on mobile will remain a curiosity. If so, it will be interesting to wait and see if Google steps in and launches their own cross-platform toolkit based on Go. Meanwhile, we look forward to the release of Go 1.5!