Data.HDiff.Patch.Merge

Merging Treefixes

After merging two patches, we might end up with a conflict. That is, two changes that can't be reconciled.

data Conflict :: (kon -> *) -> [[[Atom kon]]] -> Atom kon -> * where

Hence, a conflict is simply two changes together.

Constructors

Conflict :: String -> RawPatch ki codes at -> RawPatch ki codes at -> Conflict ki codes at

Instances

(HasDatatypeInfo ki fam codes, RendererHO ki) => Show (Holes ki codes (Sum (Conflict ki codes) (CChange ki codes)) at)

Defined in Data.HDiff.Patch.Show

Methods

showsPrec :: Int -> Holes ki codes (Sum (Conflict ki codes) (CChange ki codes)) at -> ShowS

show :: Holes ki codes (Sum (Conflict ki codes) (CChange ki codes)) at -> String

showList :: [Holes ki codes (Sum (Conflict ki codes) (CChange ki codes)) at] -> ShowS

type PatchC ki codes ix = Holes ki codes (Sum (Conflict ki codes) (CChange ki codes)) (I ix)

A PatchC is a patch with potential conflicts inside

noConflicts :: PatchC ki codes ix -> Maybe (Patch ki codes ix)

Tries to cast a PatchC back to a Patch. Naturally, this is only possible if the patch has no conflicts.

getConflicts :: ShowHO ki => PatchC ki codes ix -> [String]

Returns the labels of the conflicts ina a patch.

(//) :: (Applicable ki codes (Holes2 ki codes), EqHO ki, ShowHO ki, HasDatatypeInfo ki fam codes) => Patch ki codes ix -> Patch ki codes ix -> PatchC ki codes ix

A merge of p over q, denoted p // q, is the adaptation of p so that it could be applied to an element in the image of q.

reconcile :: forall ki codes fam at. (Applicable ki codes (Holes2 ki codes), EqHO ki, ShowHO ki, HasDatatypeInfo ki fam codes) => RawPatch ki codes at -> RawPatch ki codes at -> Holes ki codes (Sum (Conflict ki codes) (CChange ki codes)) at

The reconcile function will try to reconcile disagreeing patches.

Precondition: before calling reconcile p q, make sure p and q are different.

data ProcessOutcome ki codes

Constructors

ReturnNominator

InstDenominator (Subst ki codes (Holes2 ki codes))

CantReconcile String

rawCpy :: Map Int Int -> Holes2 ki codes at -> Bool

Checks whether a variable is a rawCpy, note that we need a map that checks occurences of this variable.

simpleCopy :: Holes2 ki codes at -> Bool

isLocalIns :: Holes2 ki codes at -> Bool

arityMap :: Holes ki codes (MetaVarIK ki) at -> Map Int Int

process :: (Applicable ki codes (Holes2 ki codes), EqHO ki, ShowHO ki) => HolesHoles2 ki codes at -> HolesHoles2 ki codes at -> ProcessOutcome ki codes

This will process two changes, represented as a spine and inner changes, into a potential merged patch. The result of process sp sq is supposed to instruct how to construct a patch that can be applied to the image sq.

We do so by traversing the places where both sp and sq differ. While we perform this traversal we instantiate a valuation of potential substitutions, which might be needed in case we need to adapt sp to sq. After we are done, we know whether we need to adapt sp, return sp as is, or there is a conflict.