[commit: packages/binary] master: Update README's example about deriving instances (cb344c2)

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Repository : ssh://git@git.haskell.org/binary

On branch  : master
Link       : http://git.haskell.org/packages/binary.git/commitdiff/cb344c27889e5cbb42dad36e2c6f1780b3c9cea2

>---------------------------------------------------------------

commit cb344c27889e5cbb42dad36e2c6f1780b3c9cea2
Author: Lennart Kolmodin <kolmodin at gmail.com>
Date:   Sun May 11 16:13:00 2014 +0400

    Update README's example about deriving instances
    
    Demonstrate how to use GHC's Generics.


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cb344c27889e5cbb42dad36e2c6f1780b3c9cea2
 README.md | 48 ++++++++++++++----------------------------------
 1 file changed, 14 insertions(+), 34 deletions(-)

diff --git a/README.md b/README.md
index 5234835..b32d7ff 100644
--- a/README.md
+++ b/README.md
@@ -54,42 +54,22 @@ the ``Get`` and ``Put`` monads.
 
 More information in the haddock documentation.
 
-## Deriving binary instances ##
+## Deriving binary instances using GHC's Generic ##
 
-It is possible to mechanically derive new instances of Binary for your
-types, if they support the Data and Typeable classes. A script is
-provided in tools/derive. Here's an example of its use.
+Beginning with GHC 7.2, it is possible to use binary serialization without
+writing any instance boilerplate code.
 
-    $ cd binary 
-    $ cd tools/derive 
-
-    $ ghci -fglasgow-exts BinaryDerive.hs
-
-    *BinaryDerive> :l Example.hs 
-
-    *Main> deriveM (undefined :: Exp)
-
-    instance Binary Main.Exp where
-      put (ExpOr a b) = putWord8 0 >> put a >> put b
-      put (ExpAnd a b) = putWord8 1 >> put a >> put b
-      put (ExpEq a b) = putWord8 2 >> put a >> put b
-      put (ExpNEq a b) = putWord8 3 >> put a >> put b
-      put (ExpAdd a b) = putWord8 4 >> put a >> put b
-      put (ExpSub a b) = putWord8 5 >> put a >> put b
-      put (ExpVar a) = putWord8 6 >> put a
-      put (ExpInt a) = putWord8 7 >> put a
-      get = do
-        tag_ <- getWord8
-        case tag_ of
-          0 -> get >>= \a -> get >>= \b -> return (ExpOr a b)
-          1 -> get >>= \a -> get >>= \b -> return (ExpAnd a b)
-          2 -> get >>= \a -> get >>= \b -> return (ExpEq a b)
-          3 -> get >>= \a -> get >>= \b -> return (ExpNEq a b)
-          4 -> get >>= \a -> get >>= \b -> return (ExpAdd a b)
-          5 -> get >>= \a -> get >>= \b -> return (ExpSub a b)
-          6 -> get >>= \a -> return (ExpVar a)
-          7 -> get >>= \a -> return (ExpInt a)
-          _ -> fail "no decoding"
+```haskell
+{-# LANGUAGE DeriveGeneric #-}
+
+import Data.Binary
+import GHC.Generics (Generic)
+
+data Foo = Foo deriving (Generic)
+
+-- GHC will automatically fill out the instance
+instance Binary Foo
+```
 
 ## Contributors ##