PyPad is a Python interpreter for iOS. This sounds incredibly exciting, right – finally I can do proper development and run Python programs on iOS! Unfortunately, that’s not really the case (mostly due to Apple’s restrictions).
PyPad lets you create multiple modules and execute each of them. However, only a subset of the standard library is available, and there’s nothing iOS-specific available (so you can’t access the camera, or touch information, and so on). Getting code in and out of the app is done via copy and paste. The standard keyboard is provided, with start/pause/stop buttons.
I keep the app installed so that I can (via AirPlay mirroring) demonstrate simple Python snippets. However, if I have an Internet connection available, then I can do that in Prompt (ssh’d to a server that has Python installed) much more elegantly.
The app is clearly limited by Apple’s restrictions as to what’s acceptable for iOS. However, it does seem like it could do much more (e.g. see Codea) if more of the standard library was available (this would mean rewriting chunks, I presume) and if there were special iOS-specific modules available for accessing things specific to the device (especially for accessing touch and graphical output). It could accept .py and text files from other applications, making it easy to get code in (e.g. from Dropbox) and share files (as text) – although perhaps that crosses Apple’s boundary for what’s ok. It would be nice to include the Python documentation, too (I have a separate app for this, but it makes sense to have it in once place).
The app is only $2, so if you’ve any interest in Python on iOS, then I’d recommend buying it to have a look and to encourage more development. You probably won’t end up using it that much, however.