diff --git a/byg/src/DependencyGenerator.hs b/byg/src/DependencyGenerator.hs
index ccbff84..f2d45e1 100644
--- a/byg/src/DependencyGenerator.hs
+++ b/byg/src/DependencyGenerator.hs
@@ -8,7 +8,7 @@ module DependencyGenerator
   , evalDepGenM
   , inject
   , onToken
-  , runFunction
+  , onTupleToken
   , runFunctionIO
   , runFunctionIO_
   , mapDepGenM
@@ -27,7 +27,7 @@ module DependencyGenerator
   ) where
 
 import Types.Token (Token(..))
-import Types.Functions (IsFunction(), IsFunctionIO(..))
+import Types.Functions (IsFunctionIO(..))
 import Types.Dependency (Action(..), F(..), Dependency, makeDependency)
 
 import Type.Reflection (Typeable, TypeRep, typeRep)
@@ -72,10 +72,12 @@ inject x = genDependency (makeDependency NoToken (Inject x))
 onToken :: (TokenableTo a t, Show a, Typeable a, Show b, Typeable b) => (a -> b) -> t -> DepGenM (Token b)
 onToken f input = do
   input' <- toToken input
-  genDependency (makeDependency input' (InlineFunction (F f)))
+  genDependency (makeDependency input' (Function (F f)))
 
-runFunction :: IsFunction f a b => f -> Token a -> DepGenM (Token b)
-runFunction f input = genDependency (makeDependency input (Function f))
+onTupleToken :: (TokenableTo a t1, Show a, Typeable a, TokenableTo b t2, Show b, Typeable b, Show r, Typeable r) => (a -> b -> r) -> t1 -> t2 -> DepGenM (Token r)
+onTupleToken f input1 input2 = do
+  tup <- toTupleToken input1 input2
+  genDependency (makeDependency tup (Function (F (uncurry f))))
 
 runFunctionIO :: IsFunctionIO f a b => f -> Token a -> DepGenM (Token b)
 runFunctionIO f input = genDependency (makeDependency input (FunctionIO f))
diff --git a/byg/src/DependencyRunner.hs b/byg/src/DependencyRunner.hs
index 4ac2b6d..005c86d 100644
--- a/byg/src/DependencyRunner.hs
+++ b/byg/src/DependencyRunner.hs
@@ -5,7 +5,7 @@ module DependencyRunner
   , runDepRunMIO
   ) where
 
-import Types (evalFunction, evalFunctionIO)
+import Types (evalFunctionIO)
 import Types.Value
 import Types.Token
 import Types.Dependency
@@ -94,9 +94,7 @@ putTokenValue t e = case t of
 
 runAction :: forall a b. Action a b -> Value -> DepRunM Value
 runAction action input = case action of
-  Function f ->
-    calc (evalFunction f)
-  InlineFunction (F f) ->
+  Function (F f) ->
     calc f
   FunctionIO f ->
     calcM (liftIO . evalFunctionIO f)
diff --git a/byg/src/Functions/General.hs b/byg/src/Functions/General.hs
index 5b40ae3..e7e4053 100644
--- a/byg/src/Functions/General.hs
+++ b/byg/src/Functions/General.hs
@@ -1,18 +1,9 @@
-{-# LANGUAGE GADTs #-}
 module Functions.General
   ( elemOf
   ) where
 
-import Types (IsFunction(..), Token)
-import DependencyGenerator (DepGenM, TokenableTo(..), toTupleToken, runFunction)
+import Types (Token)
+import DependencyGenerator (DepGenM, TokenableTo(..), onTupleToken)
 
-import Type.Reflection (Typeable, TypeRep, typeRep)
-
-
-data ElemOf a where ElemOf :: TypeRep a -> ElemOf a
-deriving instance Show (ElemOf a)
-instance (Show a, Typeable a, Eq a) => IsFunction (ElemOf a) (a, [a]) Bool where
-  evalFunction (ElemOf _) (y, ys) = y `elem` ys
-
-elemOf :: forall t a b. (Show t, Typeable t, Eq t, TokenableTo t a, TokenableTo [t] b, Typeable t) => a -> b -> DepGenM (Token Bool)
-elemOf a b = runFunction (ElemOf (typeRep :: TypeRep t)) =<< toTupleToken a b
+elemOf :: (Eq t, TokenableTo t a, TokenableTo [t] b) => a -> b -> DepGenM (Token Bool)
+elemOf = onTupleToken elem
diff --git a/byg/src/Functions/Image.hs b/byg/src/Functions/Image.hs
index 57d058b..61c0404 100644
--- a/byg/src/Functions/Image.hs
+++ b/byg/src/Functions/Image.hs
@@ -6,9 +6,9 @@ module Functions.Image
   , convertImage
   ) where
 
-import Types (IsFunction(..), IsFunctionIO(..), Token)
-import DependencyGenerator (DepGenM, TokenableTo(..), toTupleToken,
-                            runFunction, runFunctionIO, runFunctionIO_)
+import Types (IsFunctionIO(..), Token)
+import DependencyGenerator (DepGenM, TokenableTo(..), onTupleToken, toTupleToken,
+                            runFunctionIO, runFunctionIO_)
 
 import qualified Codec.Picture as CP
 import qualified Codec.Picture.STBIR as CPS
@@ -46,13 +46,9 @@ saveImage :: (TokenableTo Image a, TokenableTo FilePath b) => a -> b -> DepGenM
 saveImage a b = runFunctionIO_ SaveImage =<< toTupleToken a b
 
 
-data ConvertImage = ConvertImage deriving Show
-instance IsFunction ConvertImage (Image, ImageConversionSettings) Image where
-  evalFunction ConvertImage (ImageWrapper image, ResizeToWidth widthResized) =
-    let sizeFactor :: Double
-        sizeFactor = fromIntegral (CP.imageWidth image) / fromIntegral widthResized
-        heightResized = round (fromIntegral (CP.imageHeight image) / sizeFactor)
-    in ImageWrapper $ CPS.resize CPS.defaultOptions widthResized heightResized image
-
 convertImage :: (TokenableTo Image a, TokenableTo ImageConversionSettings b) => a -> b -> DepGenM (Token Image)
-convertImage a b = runFunction ConvertImage =<< toTupleToken a b
+convertImage = onTupleToken $ \(ImageWrapper image) (ResizeToWidth widthResized) ->
+  let sizeFactor :: Double
+      sizeFactor = fromIntegral (CP.imageWidth image) / fromIntegral widthResized
+      heightResized = round (fromIntegral (CP.imageHeight image) / sizeFactor)
+  in ImageWrapper $ CPS.resize CPS.defaultOptions widthResized heightResized image
diff --git a/byg/src/Functions/Paths.hs b/byg/src/Functions/Paths.hs
index 708ee0e..39ea60c 100644
--- a/byg/src/Functions/Paths.hs
+++ b/byg/src/Functions/Paths.hs
@@ -11,32 +11,22 @@ module Functions.Paths
 
 import Functions.Text (lowerString)
 import Functions.General (elemOf)
-import Types (IsFunction(..), IsFunctionIO(..), Token(..))
-import DependencyGenerator (DepGenM, TokenableTo(..), toTupleToken, runFunction,
+import Types (IsFunctionIO(..), Token(..))
+import DependencyGenerator (DepGenM, TokenableTo(..), onToken, onTupleToken, toTupleToken,
                             runFunctionIO, runFunctionIO_, untupleSndDepGenM)
 
 import qualified System.Directory as SD
 
-
-data JoinPaths = JoinPaths deriving Show
-instance IsFunction JoinPaths (FilePath, FilePath) FilePath where
-  evalFunction JoinPaths (s0, s1) = s0 ++ "/" ++ s1
-
 joinPaths :: (TokenableTo FilePath a, TokenableTo FilePath b) => a -> b -> DepGenM (Token FilePath)
-joinPaths a b = runFunction JoinPaths =<< TupleToken <$> toToken a <*> toToken b
-
-
-data FileComponents = FileComponents deriving Show
-instance IsFunction FileComponents FilePath (String, String) where
-  evalFunction FileComponents s =
-    let (lastRev, firstRev) = span (/= '.') $ reverse s
-        (base, ext) = case firstRev of
-          _ : firstRev' -> (reverse firstRev', reverse lastRev)
-          [] -> (reverse lastRev, "")
-    in (base, ext)
+joinPaths = onTupleToken $ \s0 s1 -> s0 ++ "/" ++ s1
 
 fileComponents :: TokenableTo FilePath a => a -> DepGenM (Token (String, String))
-fileComponents a = runFunction FileComponents =<< toToken a
+fileComponents = onToken $ \s ->
+  let (lastRev, firstRev) = span (/= '.') $ reverse s
+      (base, ext) = case firstRev of
+        _ : firstRev' -> (reverse firstRev', reverse lastRev)
+        [] -> (reverse lastRev, "")
+  in (base, ext)
 
 hasExtension :: (TokenableTo [String] a, TokenableTo FilePath b) => a -> b -> DepGenM (Token Bool)
 hasExtension exts filename = do
diff --git a/byg/src/Functions/Template.hs b/byg/src/Functions/Template.hs
index cb58cf4..322c5a7 100644
--- a/byg/src/Functions/Template.hs
+++ b/byg/src/Functions/Template.hs
@@ -4,8 +4,8 @@ module Functions.Template
   , applyTemplate
   ) where
 
-import Types (IsFunction(..), Token)
-import DependencyGenerator (DepGenM, TokenableTo(..), toTupleToken, runFunction)
+import Types (Token)
+import DependencyGenerator (DepGenM, TokenableTo(..), onTupleToken)
 
 import Data.Text (Text)
 import qualified Data.Text as T
@@ -13,21 +13,12 @@ import qualified Data.Text as T
 data Template = TemplateParts Text Text
   deriving (Eq, Show)
 
-data MakeTemplate = MakeTemplate deriving Show
-instance IsFunction MakeTemplate (Text, Text) Template where
-  evalFunction MakeTemplate (t, c) =
-    let (beforeContent, after) = T.breakOn c t
-        afterContent = T.drop (T.length c) after
-    in TemplateParts beforeContent afterContent
-
 makeTemplate :: (TokenableTo Text a, TokenableTo Text b) => a -> b -> DepGenM (Token Template)
-makeTemplate a b = runFunction MakeTemplate =<< toTupleToken a b
-
-
-data ApplyTemplate = ApplyTemplate deriving Show
-instance IsFunction ApplyTemplate (Template, Text) Text where
-  evalFunction ApplyTemplate (TemplateParts beforeContent afterContent, t) =
-    T.concat [beforeContent, t, afterContent]
+makeTemplate = onTupleToken $ \t c ->
+  let (beforeContent, after) = T.breakOn c t
+      afterContent = T.drop (T.length c) after
+  in TemplateParts beforeContent afterContent
 
 applyTemplate :: (TokenableTo Template a, TokenableTo Text b) => a -> b -> DepGenM (Token Text)
-applyTemplate a b = runFunction ApplyTemplate =<< toTupleToken a b
+applyTemplate = onTupleToken $ \(TemplateParts beforeContent afterContent) t ->
+  T.concat [beforeContent, t, afterContent]
diff --git a/byg/src/Functions/Text.hs b/byg/src/Functions/Text.hs
index e848eb8..5f3dc75 100644
--- a/byg/src/Functions/Text.hs
+++ b/byg/src/Functions/Text.hs
@@ -7,46 +7,26 @@ module Functions.Text
   , saveTextFile
   ) where
 
-import Types (IsFunction(..), IsFunctionIO(..), Token)
-import DependencyGenerator (DepGenM, TokenableTo(..), toTupleToken,
-                            runFunction, runFunctionIO, runFunctionIO_)
+import Types (IsFunctionIO(..), Token)
+import DependencyGenerator (DepGenM, TokenableTo(..), onToken, toTupleToken,
+                            runFunctionIO, runFunctionIO_)
 
 import Data.Char (toLower)
 import Data.Text (Text)
 import qualified Data.Text as T
 import qualified Data.Text.IO as T
 
-
-data ConcatStrings = ConcatStrings deriving Show
-instance IsFunction ConcatStrings [String] String where
-  evalFunction ConcatStrings = concat
-
 concatStrings :: TokenableTo [String] a => a -> DepGenM (Token String)
-concatStrings a = runFunction ConcatStrings =<< toToken a
-
-
-data ConcatTexts = ConcatTexts deriving Show
-instance IsFunction ConcatTexts [Text] Text where
-  evalFunction ConcatTexts = T.concat
+concatStrings = onToken concat
 
 concatTexts :: TokenableTo [Text] a => a -> DepGenM (Token Text)
-concatTexts a = runFunction ConcatTexts =<< toToken a
-
-
-data LowerString = LowerString deriving Show
-instance IsFunction LowerString String String where
-  evalFunction LowerString s = map toLower s
+concatTexts = onToken T.concat
 
 lowerString :: TokenableTo String a => a -> DepGenM (Token String)
-lowerString a = runFunction LowerString =<< toToken a
-
-
-data ToText = ToText deriving Show
-instance IsFunction ToText String Text where
-  evalFunction ToText s = T.pack s
+lowerString = onToken (map toLower)
 
 toText :: TokenableTo String a => a -> DepGenM (Token Text)
-toText a = runFunction ToText =<< toToken a
+toText = onToken T.pack
 
 
 data ReadTextFile = ReadTextFile deriving Show
diff --git a/byg/src/Types/Dependency.hs b/byg/src/Types/Dependency.hs
index d8d5a1b..da7a96b 100644
--- a/byg/src/Types/Dependency.hs
+++ b/byg/src/Types/Dependency.hs
@@ -11,7 +11,7 @@ module Types.Dependency
   ) where
 
 import Types.Token (Token(..))
-import Types.Functions (IsFunction(), IsFunctionIO(..))
+import Types.Functions (IsFunctionIO(..))
 
 import Type.Reflection (Typeable, TypeRep, typeRep)
 import Text.Printf (printf)
@@ -19,8 +19,7 @@ import Data.Text (Text)
 import qualified Data.Text as T
 
 data Action a b where
-  Function :: IsFunction f a b => f -> Action a b
-  InlineFunction :: (Typeable a, Typeable b, Show b) => F a b -> Action a b
+  Function :: (Typeable a, Typeable b, Show b) => F a b -> Action a b
   FunctionIO :: IsFunctionIO f a b => f -> Action a b
   Inject :: (Typeable a, Show a) => a -> Action () a
   FilterComp :: (Typeable a, Show a) => Action ([a], [Bool]) [a]
@@ -53,7 +52,6 @@ actionTargetType _ = typeRep
 actionTouchesFilesystem :: Action a b -> Bool
 actionTouchesFilesystem = \case
   Function _ -> False
-  InlineFunction _ -> False
   FunctionIO f -> functionIOTouchesFilesystem f
   Inject _ -> False
   FilterComp -> False
diff --git a/byg/src/Types/Functions.hs b/byg/src/Types/Functions.hs
index b346421..1073c14 100644
--- a/byg/src/Types/Functions.hs
+++ b/byg/src/Types/Functions.hs
@@ -1,14 +1,10 @@
 {-# LANGUAGE FunctionalDependencies #-}
 module Types.Functions
-  ( IsFunction(..)
-  , IsFunctionIO(..)
+  ( IsFunctionIO(..)
   ) where
 
 import Type.Reflection (Typeable)
 
-class (Show f, Show a, Typeable a, Show b, Typeable b) => IsFunction f a b | f -> a b where
-  evalFunction :: f -> a -> b
-
 class (Show f, Show a, Typeable a, Show b, Typeable b) => IsFunctionIO f a b | f -> a b where
   evalFunctionIO :: f -> a -> IO b
   functionIOTouchesFilesystem :: f -> Bool