Re: [Haskell-cafe] mixing map and mapM ?

Pierre-Etienne Meunier writes:

This way :

do times<-mapM PF.getFileStatus filenames >>= return.(map PF.modificationTime)

Or also :

do times<-mapM (PF.getFileStatus >>= (return.(PF.modificationTime))) filenames let sorted=...

I do not know exactly how ghc compiles the IO monad, but it seems to me that the latter would allocate a little less.

List fusion probably converts them to the same core (you can always use ghc-core to verify this if you care). -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com