Merge pull request #7 from reflex-frp/jam@fix-docs

Fix docs and add a sentence about what patch is to the readme

Author: Ericson2314

README.md

@@ -1,3 +1,13 @@
 ## Patch
 
 Infrastructure for writing patches which act on other types.
+
+A `Patch` type represents a kind of change made to a datastructure.
+
+```haskell
+class Patch p where
+  type PatchTarget p :: *
+  -- | Apply the patch p a to the value a.  If no change is needed, return
+  -- 'Nothing'.
+  apply :: p -> PatchTarget p -> Maybe (PatchTarget p)
+```

src/Data/Patch/MapWithMove.hs

@@ -25,7 +25,7 @@ import qualified Data.Set as Set
 import Data.These (These(..))
 import Data.Tuple
 
--- | Patch a DMap with additions, deletions, and moves.  Invariant: If key @k1@
+-- | Patch a Map with additions, deletions, and moves.  Invariant: If key @k1@
 -- is coming from @From_Move k2@, then key @k2@ should be going to @Just k1@,
 -- and vice versa.  There should never be any unpaired From/To keys.
 newtype PatchMapWithMove k v = PatchMapWithMove (Map k (NodeInfo k v)) deriving (Show, Eq, Ord, Functor, Foldable, Traversable)