Repository : ssh://darcs.haskell.org//srv/darcs/ghc On branch : master
http://hackage.haskell.org/trac/ghc/changeset/49ca2a37bef18aa57235ff1dbbf1cc0434979b1e >--------------------------------------------------------------- commit 49ca2a37bef18aa57235ff1dbbf1cc0434979b1e Author: Twan van Laarhoven <twa...@gmail.com> Date: Fri Nov 23 15:03:45 2012 +0100 Changed deriving of Functor, Foldable, Traversable to fix #7436. Added foldMap to derived Foldable instance. The derived instances will no longer eta-expand the function. I.e. instead of fmap f (Foo a) = Foo (fmap (\x -> f x) a) we now derive fmap f (Foo a) = Foo (fmap f a) Some superflous lambdas are generated as a result. For example data X a = X (a,a) fmap f (X x) = (\y -> case y of (a,b) -> (f a, f b)) x The optimizer should be able to simplify this code, as it is just beta reduction. The derived Foldable instance now includes foldMap in addition to foldr. compiler/prelude/PrelNames.lhs | 9 ++- compiler/typecheck/TcGenDeriv.lhs | 178 ++++++++++++++++++++++--------------- 2 files changed, 114 insertions(+), 73 deletions(-) Diff suppressed because of size. To see it, use: git show 49ca2a37bef18aa57235ff1dbbf1cc0434979b1e _______________________________________________ Cvs-ghc mailing list Cvs-ghc@haskell.org http://www.haskell.org/mailman/listinfo/cvs-ghc
