Proposal: Make intersperse lazier

The current implementation of Data.List.intersperse causes a space leak under certain not uncommon circumstances. Trac ticket: http://hackage.haskell.org/trac/ghc/ticket/4282 The proposed implementation, intersperse :: a -> [a] -> [a] intersperse _ [] = [] intersperse sep (x:xs) = x : go xs where go [] = [] go (y:ys) = sep : y : go ys changes the semantics from intersperse (x : _|_) = _|_ to intersperse (x : _|_) = x : _|_ apart from that, I think only the run-time behaviour is changed. Period of discussion: Two weeks, until 30 Sep. 2010. Cheers, Daniel