Additional Web.PathPieces.PathPiece instances to deserialize Int32, Word32, Word64, Double, Bool, TimeOfDay, UTCTime and ZonedTime

PathPieceInstances.hs

safeRead :: forall a. Read a => Text -> Maybe a
safeRead s = case (reads $ T.unpack s) of
   [(v,_)] -> Just v
   _ -> Nothing

instance PathPiece Int32 where
    fromPathPiece s =
        case Data.Text.Read.decimal s of
            Right (i, _) -> Just i
            Left _ -> Nothing
    toPathPiece = T.pack . show

instance PathPiece Word32 where
    fromPathPiece s =
        case Data.Text.Read.decimal s of
            Right (i, _) -> Just i
            Left _ -> Nothing

    toPathPiece = T.pack . show

instance PathPiece Word64 where
    fromPathPiece s =
        case Data.Text.Read.decimal s of
            Right (i, _) -> Just i
            Left _ -> Nothing

    toPathPiece = T.pack . show

instance PathPiece Double where
    fromPathPiece s =
        case Data.Text.Read.double s of
            Right (i, _) -> Just i
            Left _ -> Nothing
    toPathPiece = T.pack . show

instance PathPiece Bool where
    fromPathPiece "true" = Just True
    fromPathPiece "false" = Just False
    fromPathPiece "True" = Just True
    fromPathPiece "False" = Just False
    fromPathPiece  _ = Nothing
    toPathPiece = T.pack . show

instance PathPiece TimeOfDay where
    fromPathPiece = safeRead
    toPathPiece = T.pack . show

instance PathPiece UTCTime where
    fromPathPiece = safeRead
    toPathPiece = T.pack . show

instance PathPiece ZonedTime where
    fromPathPiece = safeRead
    toPathPiece = T.pack . show