diff --git a/Data/MemoCombinators.hs b/Data/MemoCombinators.hs
--- a/Data/MemoCombinators.hs
+++ b/Data/MemoCombinators.hs
@@ -28,8 +28,9 @@
 
 module Data.MemoCombinators 
     ( Memo
+    , wrap
     , memo2, memo3, memoSecond, memoThird
-    , bool, list, boundedList, either, maybe, unit, pair
+    , bool, char, list, boundedList, either, maybe, unit, pair
     , switch, integral, bits, unsignedBits
     , RangeMemo
     , arrayRange, unsafeArrayRange, chunks
@@ -39,10 +40,16 @@
 import Prelude hiding (either, maybe)
 import Data.Bits
 import qualified Data.Array as Array
+import Data.Char (ord,chr)
 
 -- | The type of a memo table for functions of a.
 type Memo a = forall r. (a -> r) -> (a -> r)
 
+-- | Given a memoizer for a and an isomorphism between a and b, build
+-- a memoizer for b. 
+wrap :: (a -> b) -> (b -> a) -> Memo a -> Memo b
+wrap i j m f = m (f . i) . j
+
 -- | Memoize a two argument function (just apply the table directly for
 -- single argument functions).
 memo2 :: Memo a -> Memo b -> (a -> b -> r) -> (a -> b -> r)
@@ -71,6 +78,9 @@
     where
     table nil cons [] = nil
     table nil cons (x:xs) = cons x xs
+
+char :: Memo Char
+char = wrap chr ord integral
 
 -- | Build a table which memoizes all lists of less than the given length.
 boundedList :: Int -> Memo a -> Memo [a]
diff --git a/data-memocombinators.cabal b/data-memocombinators.cabal
--- a/data-memocombinators.cabal
+++ b/data-memocombinators.cabal
@@ -1,7 +1,7 @@
 Name: data-memocombinators
 Description:
     Combinators for building memo tables.
-Version: 0.2
+Version: 0.3
 Stability: experimental
 Synopsis: Combinators for building memo tables.
 License: BSD3