Merge pull request #94 from marick/master

Added explanatory text to landing page

Author: marick

README.md

@@ -6,7 +6,26 @@
 [![Maintainer: garyb](https://img.shields.io/badge/maintainer-garyb-lightgrey.svg)](http://github.com/garyb)
 [![Maintainer: thomashoneyman](https://img.shields.io/badge/maintainer-thomashoneyman-lightgrey.svg)](http://github.com/thomashoneyman)
 
-Pure profunctor lenses.
+Pure profunctor lenses. A mechanism for updating, viewing, and setting
+values within nested data structures. As in:
+
+```purescript
+> structure = Tuple (Tuple (Tuple "hi!" 3) 2) 1
+
+> import Data.Lens
+> _leftmost = _1 <<< _1 <<< _1
+
+> view _leftmost structure
+"hi!"
+
+> set _leftmost "Bye!" structure 
+(Tuple (Tuple (Tuple "Bye!" 3) 2) 1)
+
+> over _leftmost String.toUpper structure
+(Tuple (Tuple (Tuple "HI!" 3) 2) 1)
+
+```
+
 
 ## Installation
 
@@ -20,6 +39,8 @@ Module documentation is [published on Pursuit](http://pursuit.purescript.org/pac
 
 You can find examples in the [tests](test/Main.purs) and the [examples](examples/README.md) directory.
 
+There is an [ebook](https://leanpub.com/lenses).
+
 ## Contributing
 
 Read the [contribution guidelines](https://github.com/purescript-contrib/purescript-profunctor-lenses/blob/master/.github/contributing.md) to get started and see helpful related resources.