[seanmcdirmid]

Squeak supports two kinds of liveness. The first is general hotswapping, which appears in mainstream languages (though not done as well as smalltalk), and as mentioned, isn't very live. Once you add the loop, you still have lots of problems to solve (e.g. is their encapsulated state, how is the state upgraded on a code change?). To make it live requires huge compromises, and anyways you could make the same modification with any language that supports hotswapping.

The second is direct object manipulation via morphic, which is quite different from manipulating the program via its code. The line is blurred a bit given that Squeak is image based (so changes to objects that you make will persist).