Even mozilla firefox is banned on the premise that it can run arbitrary code and yes, that is the official apple instance.
The fact that they apply it when they see fit and allow other times, and that it is totally arbitrary and opaque based on their own private interests, is exactly what everyone with common sense tried to explain when criticizing the walled garden.
My understanding is that what's banned on iOS is not arbitrary code per se, it's arbitrary code downloaded from the internet. Code you enter yourself, like in Pythonista, is just fine.
Isn't the problem JITing? Mozilla could ship Firefox, even with the JS engine, it would simply be unusable (compared to Safari) because they wouldn't be allowed to run JIT (only interpreter).
Firefox isn't banned, Gecko and SpiderMonkey are. For a few reasons, Apple doesn't want Blink/V8 demolishing users' batteries, and they have the excuse that allowing 3rd party browser engines is a security risk.
It is.
Even mozilla firefox is banned on the premise that it can run arbitrary code and yes, that is the official apple instance.
The fact that they apply it when they see fit and allow other times, and that it is totally arbitrary and opaque based on their own private interests, is exactly what everyone with common sense tried to explain when criticizing the walled garden.