On Sat, Dec 09, 2006 at 11:50:57AM -0800, Jason Dagit wrote: > On 12/9/06, David Roundy <[EMAIL PROTECTED]> wrote: > >Hi all, > > > >I've just started (an hour ago) converting all the (PatchInfo, Maybe Patch) > >instances in darcs to (PatchInfo, Hopefully Patch) where > > > >data Hopefully a = Actually a | Unavailable String > > Is there a reason to not use 'Either a String' instead? That's the > common way to handle error propagation (Either is a commonly used > instance of MonadError). > > Obviously creating new datatypes is easy in Haskell, but is it the > right thing here? Maybe we just need 'type Hopefully a = Either a > String' instead.
I started out with type Hopefully = Either String, but you can't make that a monad, since it overlaps with MonadError. And there's a lot of Eithers in the code already, and I'd like to be able to easily and typesafely change just one of them. -- David Roundy Department of Physics Oregon State University _______________________________________________ darcs-devel mailing list [email protected] http://www.abridgegame.org/cgi-bin/mailman/listinfo/darcs-devel
