diff --git a/raft.cabal b/raft.cabal
--- a/raft.cabal
+++ b/raft.cabal
@@ -1,20 +1,20 @@
 name               : raft
-version            : 0.3.11.0
+version            : 0.4.0.0
 synopsis           : Miscellaneous Haskell utilities for data structures and data manipulation.
 description        : This Haskell library contains miscellaneous data structures and data manipulation functions for general uses.
 
 license            : MIT
 license-file       : LICENSE
-author             : Brian W Bush <consult@brianwbush.info>
-maintainer         : Brian W Bush <consult@brianwbush.info>
-copyright          : (c) 2005-17 Brian W Bush
+author             : Brian W Bush <code@functionally.io>
+maintainer         : Brian W Bush <code@functionally.io>
+copyright          : (c) 2005-19 Brian W Bush
 category           : Data
 stability          : Experimental
 build-type         : Simple
 cabal-version      : >= 1.10
 homepage           : https://bitbucket.org/functionally/raft
 bug-reports        : https://bwbush.atlassian.net/projects/HRAFT/issues/
-package-url        : https://bitbucket.org/functionally/raft/downloads/raft-0.3.7.2.tar.gz
+package-url        : https://bitbucket.org/functionally/raft/downloads/raft-0.4.0.0.tar.gz
 
 source-repository head
   type             : mercurial
diff --git a/src/Control/Monad/Except/Util.hs b/src/Control/Monad/Except/Util.hs
--- a/src/Control/Monad/Except/Util.hs
+++ b/src/Control/Monad/Except/Util.hs
@@ -26,10 +26,12 @@
 , guardIO
 , eitherError
 , runToIO
+-- * Exceptions
+, guardSomeException
 ) where
 
 
-import Control.Exception (IOException, throw, try)
+import Control.Exception (IOException, SomeException, throw, try)
 import Control.Monad (unless, when)
 import Control.Monad.Except (ExceptT, MonadError, MonadIO, liftIO, runExceptT, throwError)
 import Data.String (IsString(..))
@@ -47,6 +49,14 @@
   (either (throwError . show) return =<<)
     . liftIO
     . tryIOError
+
+
+-- | Catch any exception and throw it into 'MonadError String'.
+guardSomeException :: (MonadIO m, MonadError String m) => IO a -> m a
+guardSomeException =
+  (either (throwError . (show :: SomeException -> String)) return =<<)
+    . liftIO
+    . try
 
 
 -- | Throw 'Data.Either.Left' into 'Control.Exception.IOException'.
diff --git a/src/Data/Function/MapReduce/Internal.hs b/src/Data/Function/MapReduce/Internal.hs
--- a/src/Data/Function/MapReduce/Internal.hs
+++ b/src/Data/Function/MapReduce/Internal.hs
@@ -42,11 +42,10 @@
 
 
 -- | Functiom for mapping and then reducing.
-type MapReduce a k v b =  Ord k
-               => (a -> (k, v))   -- ^ Function for mapping to keys and values.
-               -> (k -> [v] -> b) -- ^ Function for reducing values.
-               -> [a]             -- ^ The values.
-               -> [b]             -- ^ The reduced values.
+type MapReduce a k v b =  (a -> (k, v))   -- ^ Function for mapping to keys and values.
+                       -> (k -> [v] -> b) -- ^ Function for reducing values.
+                       -> [a]             -- ^ The values.
+                       -> [b]             -- ^ The reduced values.
 
 
 -- | Reduce values by group.
diff --git a/src/Data/List/Util/Listable.hs b/src/Data/List/Util/Listable.hs
--- a/src/Data/List/Util/Listable.hs
+++ b/src/Data/List/Util/Listable.hs
@@ -15,6 +15,7 @@
 
 {-# LANGUAGE FlexibleInstances      #-}
 {-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE MonoLocalBinds         #-}
 {-# LANGUAGE MultiParamTypeClasses  #-}
 {-# LANGUAGE Safe                   #-}
 
diff --git a/src/Data/Table/Identifier.hs b/src/Data/Table/Identifier.hs
--- a/src/Data/Table/Identifier.hs
+++ b/src/Data/Table/Identifier.hs
@@ -14,6 +14,7 @@
 
 
 {-# LANGUAGE FlexibleInstances         #-}
+{-# LANGUAGE MonoLocalBinds            #-}
 
 {-# OPTIONS_GHC -fno-warn-deprecations #-}
 
@@ -24,6 +25,7 @@
 ) where
 
 
+import Data.String.Util (Stringy(..))
 import Data.Table (Tabulatable(..))
 
 
@@ -31,12 +33,7 @@
 newtype Id a = Id {unId :: a}
   deriving (Read, Show)
 
-instance Tabulatable (Id String) where
-  labels = const ["ID"]
-  tabulation = (: []) . unId
-  untabulation = Id . head
-
-instance (Read a, Show a) => Tabulatable (Id a) where
+instance Stringy a => Tabulatable (Id a) where
   labels = const ["ID"]
-  tabulation = (: []) . show . unId
-  untabulation = Id . read . head
+  tabulation = (: []) . toString . unId
+  untabulation = Id . fromString . head
diff --git a/src/Data/Tabular.hs b/src/Data/Tabular.hs
--- a/src/Data/Tabular.hs
+++ b/src/Data/Tabular.hs
@@ -15,6 +15,7 @@
 
 {-# LANGUAGE FlexibleInstances    #-}
 {-# LANGUAGE Safe                 #-}
+{-# LANGUAGE MonoLocalBinds         #-}
 {-# LANGUAGE TupleSections        #-}
 {-# LANGUAGE UndecidableInstances #-}
 
@@ -31,7 +32,7 @@
 ) where
 
 
-import Control.Monad (ap, liftM)
+import Control.Monad (ap)
 import Data.List (intercalate)
 import Data.List.Split (splitOn)
 
@@ -117,7 +118,7 @@
 readTabular :: Tabular a
   => FilePath -- ^ The filename.
   -> IO [a]   -- ^ Action to read the data.
-readTabular = liftM (checkHeader . read) . readFile
+readTabular = fmap (checkHeader . read) . readFile
 
 
 -- | Write tabular data.
diff --git a/src/Data/Tuple/Util.hs b/src/Data/Tuple/Util.hs
--- a/src/Data/Tuple/Util.hs
+++ b/src/Data/Tuple/Util.hs
@@ -14,6 +14,7 @@
 
 
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE MonoLocalBinds   #-}
 {-# LANGUAGE Safe             #-}