diff --git a/Spintax.cabal b/Spintax.cabal
--- a/Spintax.cabal
+++ b/Spintax.cabal
@@ -1,5 +1,5 @@
 name:                Spintax
-version:             0.1.0.1
+version:             0.2.0.0
 synopsis:            Random text generation based on spintax
 description:         Random text generation based on spintax with nested alternatives and empty options.
 homepage:            https://github.com/MichelBoucey/spintax
@@ -7,21 +7,21 @@
 license-file:        LICENSE
 author:              Michel Boucey
 maintainer:          michel.boucey@cybervisible.fr
-copyright:           Copyright (c) 2016 - Michel Boucey
+copyright:           (c) 2016 - Michel Boucey
 category:            Text
 build-type:          Simple
 cabal-version:       >=1.10
 
 library
-  hs-source-dirs:      src
-  exposed-modules:     Text.Spintax
-  build-depends:       base >= 4.7 && < 5
-                     , text
-                     , attoparsec
-                     , mwc-random
-                     , extra
-  default-language:    Haskell2010
-  GHC-Options:         -Wall
+  hs-source-dirs:    src
+  exposed-modules:   Text.Spintax
+  build-depends:     base >= 4.7 && < 5
+                   , text
+                   , attoparsec
+                   , mwc-random
+                   , extra
+  default-language:  Haskell2010
+  GHC-Options:       -Wall
 
 source-repository head
   type:     git
diff --git a/src/Text/Spintax.hs b/src/Text/Spintax.hs
--- a/src/Text/Spintax.hs
+++ b/src/Text/Spintax.hs
@@ -11,10 +11,10 @@
 
 -- | Generate random texts based on a spinning syntax template, with nested alternatives and empty options.
 --
--- >λ> spintax {{Oh my God|Awesome}, {a|the}|A|The} {quick {and dirty |||}||}{brown |pink |grey |}{fox|flea|elephant} jumps over {the|a} {lazy |smelly |sleepy |}{dog|cat|whale}{.|!|...}
+-- >λ> spintax "{{Oh my God|Awesome}, {a|the}|A|The} {quick {and dirty |||}||}{brown |pink |grey |}{fox|flea|elephant} jumps over {the|a} {lazy |smelly |sleepy |}{dog|cat|whale}{.|!|...}"
 -- > Right "Awesome, the quick pink fox jumps over a sleepy whale."
 --
-spintax :: T.Text -> IO (Either T.Text T.Text)
+spintax :: T.Text -> IO (Either String T.Text)
 spintax template =
   createSystemRandom >>= flip runParse template
     where
@@ -37,13 +37,15 @@
                 Done r m ->
                   case m of
                     "{" -> go g o (add as m) r (l+1)
-                    "}" -> do r' <- runParse g =<< randAlter g as
-                              case r' of
-                                Left _ -> failure
-                                Right t -> go g (o <> t) [] r (l-1)
-                    "|" -> if E.null as
-                             then go g o ["",""] r l
-                             else go g o (E.snoc as "") r l
+                    "}" -> do
+                      r' <- runParse g =<< randAlter g as
+                      case r' of
+                        Left _ -> failure
+                        Right t -> go g (o <> t) [] r (l-1)
+                    "|" ->
+                      if E.null as
+                        then go g o ["",""] r l
+                        else go g o (E.snoc as "") r l
                     _   -> go g o (add as m) r l
                 Partial _ -> failure
                 Fail {} -> failure
@@ -78,6 +80,6 @@
                           ctt _   = True
           go _ _ _ _ _ = failure
 
-failure :: IO (Either T.Text b)
-failure = return $ Left "Spintax template parsing failure"
+failure :: IO (Either String b)
+failure = fail "Spintax template parsing failure"