ipython/ipython — pull request #1073 by takluyver (2011-11-30 22:28:18+00:00)
Title: Storemagic plugin

This makes the storemagic extension a plugin, so there's a configurable option for autorestoring variables on startup (default False).

It also adds a non-configurable `default_extensions` trait to InteractiveShellApp, for extensions we want to always load as part of IPython. I considered just having a default value for the `extensions` trait, but I think that's too easy to clobber unintentionally in config, e.g. `c.InteractiveShellApp.extensions = ['sympyprinting']`.

I think this is a shortcoming of the extension system, that there isn't a simple way to add values to a container - you have to do the little dance with hasattr, and then assign or use `extend`.