Darcs.Hopefully

Documentation

data Hopefully a

Hopefully p C (x y) is Either String (p C (x y)) in a form adapted to darcs patches. The C (x y) represents the type witness for the patch that should be there. The Hopefully type just tells whether we expect the patch to be hashed or not, and SimpleHopefully does the real work of emulating Either. Hopefully sh represents an expected unhashed patch, and Hashed hash sh represents an expected hashed patch with its hash.

data PatchInfoAnd p

PatchInfoAnd p represents a hope we have to get a patch through its info. We're not sure we have the patch, but we know its info.

Instances

MyEq p => MyEq (PatchInfoAnd p)

Invert p => Invert (PatchInfoAnd p)

ReadPatch p => ReadPatch (PatchInfoAnd p)

(Conflict p, Effect p, ShowPatch p) => ShowPatch (PatchInfoAnd p)

Commute p => Commute (PatchInfoAnd p)

Apply p => Apply (PatchInfoAnd p)

RepoPatch p => Patchy (PatchInfoAnd p)

Effect p => Effect (PatchInfoAnd p)

Conflict p => Conflict (PatchInfoAnd p)

data WPatchInfo

WPatchInfo represents the info of a patch, marked with the patch's witnesses.

Instances

MyEq WPatchInfo

unWPatchInfo :: WPatchInfo -> PatchInfo

compareWPatchInfo :: WPatchInfo -> WPatchInfo -> EqCheck

piap :: PatchInfo -> Named p -> PatchInfoAnd p

piap i p creates a PatchInfoAnd containing p with info i.

n2pia :: Named p -> PatchInfoAnd p

n2pia creates a PatchInfoAnd representing a Named patch.

patchInfoAndPatch :: PatchInfo -> Hopefully (Named p) -> PatchInfoAnd p

conscientiously :: (Doc -> Doc) -> PatchInfoAnd p -> Named p

conscientiously er hp tries to extract a patch from a PatchInfoAnd. If it fails, it applies the error handling function er to a description of the patch info component of hp.

hopefully :: PatchInfoAnd p -> Named p

hopefully hp tries to get a patch from a PatchInfoAnd value. If it fails, it outputs an error "failed to read patch: <description of the patch>". We get the description of the patch from the info part of hp

info :: PatchInfoAnd p -> PatchInfo

winfo :: PatchInfoAnd p -> WPatchInfo

hopefullyM :: Monad m => PatchInfoAnd p -> m (Named p)

hopefullyM is a version of hopefully which calls fail in a monad instead of erroring.

createHashed :: String -> (String -> IO (Sealed a)) -> IO (Sealed (Hopefully a))

extractHash :: PatchInfoAnd p -> Either (Named p) String

actually :: a -> Hopefully a

unavailable :: String -> Hopefully a

patchDesc :: forall p. PatchInfoAnd p -> String