Re: [Haskell-cafe] Eta-expansion and existentials (or: types destroy my laziness)

On 16 October 2010 12:16, Roman Leshchinskiy wrote:

eta :: Stream a -> Stream a eta s = Stream s next   where     next (Stream s next') = case next' s of                               Just (x,s') -> Just (x,Stream s' next')                               Nothing     -> Nothing

Making GHC optimise stream code involving eta properly is hard :-)

Good point, I don't exactly mean non-recursive for requirement 3) then - I mean an adjective with a fuzzier definition like "GHC-optimisable" :-) Max