Use this function to evaluate code or run actions that should mimic the user's interactions. For example, DrScheme uses this function to evaluate expressions in the definitions window and expressions submitted at the prompt.
The function run-loop is called. It is expected to loop, calling it's argument with a thunk that corresponds to the user's evaluation. It should call it's argument once for each expression the user is evaluating. It should pass a thunk to it's argument that actually does the users's evaluation.