[darcs-devel] changing (PatchInfo, Maybe Patch) to (PatchInfo, Hopefully Patch)

[David Roundy]

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

which also is an instance of Monad, Functor, etc.

The idea is twofold.  One benefit is that it allows us to carry around
failure information when reading a patch fails (good for ssh errors, etc).
The other is that it may be helpful for the hashed inventories.  You can
expect a (very large!) patch later today.  I'm sending a heads-up now, in
case there are any improvements you'd like to suggest.
-- 
David Roundy
Department of Physics
Oregon State University