On Thu, 6 May 2010 15:07:30 +1000 Ivan Miljenovic <ivan.miljeno...@gmail.com> wrote:
> On 6 May 2010 15:01, <bri...@aracnet.com> wrote: > > > > I was doing the following: > > > > > > do status <- mapM PF.getFileStatus filenames > > let times = map PF.modificationTime status > > let sorted = sortBy (\(_, t1) (_,t2) -> compare t1 t2) (zip > > filenames times) > > times <- mapM (liftM PF.modificationTime . PF.getFileStatus) filenames > > However, I'd be tempted to leave it as is (and hope/assume that fusion > does its magic). > well now it's obvious :-) I did have liftM in there, but just couldn't quite figure out how to tie things together. to be completely clear : liftM takes modificationTime from Status -> EpochTime to IO Status -> IO EpochTime so now it can operate on the results of getFileStatus, which returns `IO Status`. mapM gathers the [IO EpochTime] into `IO [EpochTime]` and then <- gives [EpochTime]. It's a little more clear in the verbose form, isn't it ? Thanks ! Brian _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
