diff --git a/chapter10/generics.hs b/chapter10/generics.hs
index 3a84874..d289075 100644
--- a/chapter10/generics.hs
+++ b/chapter10/generics.hs
@@ -31,6 +31,18 @@ class GEq a where
   default geq :: (Generic a, GEq' (Rep a)) => a -> a -> Bool
   geq x y = geq' (from x) (from y)
 
-instance GEq Char   where geq = (==)
-instance GEq Int    where geq = (==)
-instance GEq Float  where geq = (==)
+-- Base equalities
+instance GEq Char where geq = (==)
+instance GEq Int where geq = (==)
+instance GEq Float where geq = (==)
+
+-- Equalities derived from structure of (:+:) and (:*:)
+instance GEq a => GEq (Maybe a)
+instance (GEq a, GEq b) => GEq (a,b)
+
+main :: IO ()
+main = do
+  print $ geq 2 (3 :: Int)
+  print $ geq 'a' 'b'
+  print $ geq (Just 'a') (Just 'a')
+  print $ geq ('a','b') ('a', 'b')
diff --git a/chapter9/assign/README.md b/chapter9/assign/README.md
new file mode 100644
index 0000000..d8f1130
--- /dev/null
+++ b/chapter9/assign/README.md
@@ -0,0 +1,6 @@
+Assign
+------
+
+```bash
+$ stack exec assign input.test
+```
diff --git a/chapter9/assign/happy.cabal b/chapter9/assign/assign.cabal
similarity index 93%
rename from chapter9/assign/happy.cabal
rename to chapter9/assign/assign.cabal
index ed65d8d..e70e190 100644
--- a/chapter9/assign/happy.cabal
+++ b/chapter9/assign/assign.cabal
@@ -6,7 +6,7 @@ cabal-version:       >=1.10
 
 executable assign
   build-depends:       
-      base       >= 4.6 && <4.7
+      base       >= 4.6 && <4.9
     , containers >= 0.5 && <0.6
     , mtl        >= 2.2
   default-language:    Haskell2010
diff --git a/chapter9/assign/stack.yaml b/chapter9/assign/stack.yaml
new file mode 100644
index 0000000..02c0265
--- /dev/null
+++ b/chapter9/assign/stack.yaml
@@ -0,0 +1,6 @@
+resolver: lts-3.16
+packages:
+- '.'
+extra-deps: []
+flags: {}
+extra-package-dbs: []
diff --git a/chapter9/attoparsec/simple.ml b/chapter9/attoparsec/simple.ml
new file mode 100644
index 0000000..7d02371
--- /dev/null
+++ b/chapter9/attoparsec/simple.ml
@@ -0,0 +1 @@
+(\x -> x)