It's such a shame the licensing of Wolfram Mathematica is so strict and pricing is high. I get it, it's the fruit of a lot of hard work but sadly it won't get the traction it deserves.
I had no idea the Wolfram Cloud had grown so useful. If you're here reading comments to see if the article is worth it: It shows how small snippets of code in the Wolfram Language get packaged as an "app" via a companion app on iPhone (which seems like a runtime essentially). That iPhone app also has an Apple Watch component to surface the packaged Wolfram Code app on the watch. Tons of quick examples of pretty clever things.
I bought the Home edition of Mathematica, and have always enjoyed using it. You can program in many paradigms, functional, rules-based, imperative, etc...
The hooks to the data and the notebook interface, far before iPython, iJulia, Beaker and others came along, so it has a head start with integration, and as another wrote below, a great standard library.
How does this get around the App Store Review Guidelines?<p><pre><code> 2.7: Apps that download code in any way or form will be rejected
2.8: Apps that install or launch other executable code will be rejected</code></pre>