diff --git a/GroteTrap.cabal b/GroteTrap.cabal
--- a/GroteTrap.cabal
+++ b/GroteTrap.cabal
@@ -1,5 +1,5 @@
 Name:           GroteTrap
-Version:        0.2
+Version:        0.3
 Synopsis:       GroteTrap
 Description:    Allows quick definition of expression languages. You get a parser for free, as well as conversion from text selection to tree selection and back.
 
@@ -14,7 +14,7 @@
 Build-type:     Simple
 
 Library
-  Build-Depends:    base, QuickCheck, parsec, mtl
+  Build-Depends:    base, QuickCheck, parsec <= 2.1.0.0, mtl
   Exposed-Modules:  Language.GroteTrap.Range
                     Language.GroteTrap.Trees
                     Language.GroteTrap.Language
diff --git a/Language/GroteTrap/Language.hs b/Language/GroteTrap/Language.hs
--- a/Language/GroteTrap/Language.hs
+++ b/Language/GroteTrap/Language.hs
@@ -2,7 +2,7 @@
 module Language.GroteTrap.Language (
 
   -- * Language
-  Language(..),
+  Language(..), language,
   
   -- * Operators
   Operator(..),
@@ -25,12 +25,20 @@
 
 -- | Language connects the syntax of identifiers, numbers, operators and functions with their semantics. GroteTrap is able to derive a parser and evaluator from a Language, as well as convert between source text selections and tree selections.
 data Language a  =   Language
-  { variable     ::  (String -> a)
-  , number       ::  (Int -> a)
+  { variable     ::  String -> a
+  , number       ::  Int -> a
   , operators    ::  [Operator a]
   , functions    ::  [Function a]
   }
 
+-- | An empty language. Use this as the starting base of your languages, setting only those fields that are of importance.
+language :: Language a
+language = Language
+  { variable    = error "variables are not supported"
+  , number      = error "numbers are not supported"
+  , operators   = []
+  , functions   = []
+  }
 
 ------------------------------------
 -- Operators
diff --git a/Language/GroteTrap/Lexer.hs b/Language/GroteTrap/Lexer.hs
--- a/Language/GroteTrap/Lexer.hs
+++ b/Language/GroteTrap/Lexer.hs
@@ -33,7 +33,7 @@
 
 type TokenPos = (Pos, Token)
 
--- | When giver a language, transforms a list of characters into a list of tokens.
+-- | When given a language, transforms a list of characters into a list of tokens.
 tokenize :: Language a -> Parser [TokenPos]
 tokenize = many . pToken
 
diff --git a/Language/GroteTrap/Parser.hs b/Language/GroteTrap/Parser.hs
--- a/Language/GroteTrap/Parser.hs
+++ b/Language/GroteTrap/Parser.hs
@@ -34,7 +34,7 @@
 
 -- | Given a language and a string, parses and evaluates the string.
 readExpression :: Language a -> String -> a
-readExpression lang = evaluate lang . resultOf . parseSentence lang
+readExpression lang = evaluate lang . readParseTree lang
 
 combine :: Parser [TokenPos] -> GenParser TokenPos () c -> String -> Either ParseError c
 combine p1 p2 input = case runParser p1 () "characters" input of
diff --git a/Language/GroteTrap/Trees.hs b/Language/GroteTrap/Trees.hs
--- a/Language/GroteTrap/Trees.hs
+++ b/Language/GroteTrap/Trees.hs
@@ -155,7 +155,7 @@
 
 -- | Selects part of a tree.
 select :: (Monad m, Tree t) => t -> TreeSelection -> m [t]
-select t (path, offset) = (sequence . map (followM t) . take offset . iterate right) path
+select t (path, offset) = (sequence . map (followM t) . take (offset + 1) . iterate right) path
 
 -- | Computes the range of a valid selection.
 selectionToRange :: (Tree a, KnowsPosition a) => a -> TreeSelection -> Range