diff --git a/Data/Syntax/Combinator.hs b/Data/Syntax/Combinator.hs
--- a/Data/Syntax/Combinator.hs
+++ b/Data/Syntax/Combinator.hs
@@ -1,7 +1,7 @@
 {- |
 Module      :  Data.Syntax.Combinator
 Description :  Combinators that work with any sequence type.
-Copyright   :  (c) Paweł Nowak
+Copyright   :  (c) Daan Leijen 1999-2001, Bryan O'Sullivan 2007-2014, Paweł Nowak 2014
 License     :  MIT
 
 Maintainer  :  Paweł Nowak <pawel834@gmail.com>
@@ -15,16 +15,7 @@
 import Control.Lens.SemiIso
 import Data.SemiIsoFunctor
 
--- | Zero or more occurences of @v@ separated by @s@.
-sepBy :: SemiIsoAlternative f => f a -> f () -> f [a]
-sepBy v s =  sepBy1 v s 
-         /|/ sipure _Empty
-
--- | One or more occurences of @v@ separated by @s@.
-sepBy1 :: SemiIsoAlternative f => f a -> f () -> f [a]
-sepBy1 v s = _Cons /$/ v /*/ (s */ sepBy1 v s /|/ sipure _Empty)
-
--- | One or none occurences of @f@.
+-- | One or zero occurences of @f@.
 optional :: SemiIsoAlternative f => f a -> f (Maybe a)
 optional f = _Just /$/ f /|/ sipure _Nothing
 
@@ -32,7 +23,30 @@
 opt :: SemiIsoAlternative f => f () -> f ()
 opt f = f /|/ sipure id
 
--- | Parser one or more occurences of @f@, but prints nothing.
+-- | Parser one or zero occurences of @f@, but prints nothing.
 opt_ :: SemiIsoAlternative f => f () -> f ()
 opt_ f =  semiIso (const (Left "opt_")) Right /$/ f
       /|/ sipure id
+
+-- | @manyTill p end@ applies action p zero or more times until action
+-- end succeeds, and returns the list of values returned by p.
+manyTill :: SemiIsoAlternative f => f a -> f () -> f [a]
+manyTill p end =  _Empty /$/ end
+              /|/ _Cons /$/ p /*/ manyTill p end
+
+-- | Zero or more occurences of @v@ separated by @s@.
+sepBy :: SemiIsoAlternative f => f a -> f () -> f [a]
+sepBy v s = sepBy1 v s /|/ sipure _Empty
+
+-- | One or more occurences of @v@ separated by @s@.
+sepBy1 :: SemiIsoAlternative f => f a -> f () -> f [a]
+sepBy1 v s = _Cons /$/ v /*/ (s */ sepBy1 v s /|/ sipure _Empty)
+
+-- | Tries to apply the actions in the list in order, until one of
+-- them succeeds. Returns the value of the succeeding action.
+choice :: SemiIsoAlternative f => [f a] -> f a
+choice = foldr (/|/) (sifail "choice: all alternatives failed")
+
+-- | Combine two alternatives.
+eitherOf :: SemiIsoAlternative f => f a -> f b -> f (Either a b)
+eitherOf a b = _Left /$/ a /|/ _Right /$/ b
diff --git a/syntax.cabal b/syntax.cabal
--- a/syntax.cabal
+++ b/syntax.cabal
@@ -1,15 +1,28 @@
 name:                syntax
-version:             0.2.0.0
-synopsis:            Abstract syntax descriptions for parsing and pretty-printing.
-description:         Abstract syntax descriptions for parsing and pretty-printing.
-                     Write a single syntax description, get both a parser and a pretty-printer.
-                     .
-                     Syntax descriptions are based on semi-isomorphisms from @semi-iso@ library.
-                     .
-                     The library is very young. There are lots of useful combinators that could be written.
-                     .
-                     See @syntax-example@ for an example, @syntax-attoparsec@ and @syntax-pretty@ for
-                     a parser/printer implementation.
+version:             0.2.1.0
+synopsis:            Syntax descriptions for unified parsing and pretty-printing.
+description:
+  'syntax' allows you to write a single syntax description and instantiate is both as a parser and a pretty printer.
+  .
+  The interface is based on a custom Functor/Applicative/Monad hierarchy, provided by the 'semi-iso' package. You fmap using
+  a semi-isomorphism instead of function. A semi-isomorphism is a isomorphism that can fail in both directions, with slightly
+  weakened laws. It is worth to note that @Iso@s and @Prism@s from 'lens' are valid semi-isomorphisms :)
+  .
+  Once you write a description you can, for example turn it into an Attoparsec parser.
+  .
+  See @syntax-example@ for an example, 'syntax-attoparsec' and 'syntax-pretty' for a parser/printer implementation.
+  .
+  The library was inspired by:
+  .
+  * Rendel, Tillmann, and Klaus Ostermann. "Invertible syntax descriptions: unifying parsing and pretty printing." ACM Sigplan Notices. Vol. 45. No. 11. ACM, 2010.
+  .
+  TODO:
+  .
+  * a printer library based on Text/ByteString builders (wrapping 'pretty' is inefficient and doesn't use any features of it),
+  * try to implement indentation and Haskell layout rule,
+  * combinators for binary data formats, vectors,
+  * implementation of do notation for SemiIsoMonad with QuasiQuoters.
+
 license:             MIT
 license-file:        LICENSE
 author:              Paweł Nowak
@@ -27,5 +40,5 @@
   exposed-modules:     Data.Syntax
                        Data.Syntax.Char
                        Data.Syntax.Combinator
-  build-depends:       base >= 4 && < 5, mono-traversable, lens >= 4, semi-iso >= 0.4, scientific >= 0.3
+  build-depends:       base >= 4 && < 5, mono-traversable, lens >= 4, semi-iso >= 0.4.1, scientific >= 0.3
   default-language:    Haskell2010