On Aug 18, 2006, at 1:06 PM, pepe wrote:

If you have gone that far and modified ghci, wouldn't it be easier to disable the :load command and hardwire the loading of the UserLayer module ?

Ah, but the thing is that the UserLayer is written by the user and so we don't know what it is before-hand. Also, the user should be able to switch between different Layers without destroying the application state.

1) CAFs (Constant Applicative Form) are essentially top level bindings. Top level bindings are closures, as anything in ghc, and they are in suspended state until they are evaluated. When this happens the closure is updated to store the computed value, and because of this evaluation effectively happens only once.

2) I don't know, but probably you will notice during your experiments

3) Probably no. What happens to top level bindings in the interactive environment? I think that you lose that environment too after load and some other commands. An option is to identify and disable all these commands.

I don't want to disable the commands, just the clearing of the environment. At the moment I never revert the CAFs so I'm hoping that the environment will be preserved whatever I the user does. / Ulf