Add lower bounds to package description

Also some refactoring/reformatting

Author: mpilgrem

casa-types/casa-types.cabal

@@ -35,13 +35,13 @@ library
       src
   ghc-options: -Wall
   build-depends:
-      aeson
-    , attoparsec
-    , base
-    , base16-bytestring >=1
-    , bytestring
-    , hashable
-    , path-pieces
-    , persistent
-    , text
+      aeson >=0.5.0.0
+    , attoparsec >=0.10.0.0
+    , base >=4.8 && <5
+    , base16-bytestring >=1.0.0.0
+    , bytestring >=0.10.2.0
+    , hashable >=1.1.2.0
+    , path-pieces >=0.1.0
+    , persistent >=1.2.0
+    , text >=0.11.1.5
   default-language: Haskell2010

casa-types/src/Casa/Types.hs

@@ -45,26 +45,23 @@ instance ToJSON BlobKey where
 
 instance PathPiece BlobKey where
 
-  fromPathPiece =
-    either (const Nothing) Just .
-    blobKeyHexParser
+  fromPathPiece = either (const Nothing) Just . blobKeyHexParser
 
   toPathPiece = T.decodeUtf8 . Hex.encode . unBlobKey
 
 -- | Parse a blob key in hex format.
 blobKeyHexParser :: Text -> Either String BlobKey
 blobKeyHexParser =
-  Atto.T.parseOnly
-    (fmap
-       BlobKey
-       (do bytes <- Atto.T.take 64
-           case Hex.decode (T.encodeUtf8 bytes) of
-             Right result -> pure result
-             Left _ -> fail "Invalid hex key."))
+  Atto.T.parseOnly $
+    BlobKey <$> do
+      bytes <- Atto.T.take 64
+      case Hex.decode (T.encodeUtf8 bytes) of
+        Right result -> pure result
+        Left _ -> fail "Invalid hex key."
 
 -- | Parse a blob key in binary format.
 blobKeyBinaryParser :: Atto.B.Parser BlobKey
-blobKeyBinaryParser = fmap BlobKey (Atto.B.take 32)
+blobKeyBinaryParser = BlobKey <$> Atto.B.take 32
 
 -- | Yield a t'S.Builder' value corresponding to the given t'BlobKey' value.
 blobKeyToBuilder :: BlobKey -> S.Builder