First of all, I am very strongly in favor of Lennart's proposal of slowing down the BBP. This discussion is now moving in the direction of changes or alternatives to BBP itself. That is a worthwhile discussion, but it's not practical until we first come to a conclusion about Lennart's original proposal. For now, what is on the table is to find a way to swap BBP, exactly as it is now, in or out using some simple mechanism like a pragma. The proposed syntax LANGUAGE Prelude=AlternativePrelude is nice, but the difficulty in finding a Proposal 3 shows that this syntax is not good enough. We need a combined Proposal 1 and Proposal 3 that works something like this: The base package comes with two versions of each of the affected modules. Something like this: Prelude.Traditional Prelude.Alternative Data.List.Traditional Data.List.Alternative etc. Then we need some simple mechanism - a LANGUAGE pragma, or whatever - that swaps all at once which of the two sets are re-exported by the standard modules. -Yitz