diff --git a/byg/byg.cabal b/byg/byg.cabal
index 2436f7c..7bac461 100644
--- a/byg/byg.cabal
+++ b/byg/byg.cabal
@@ -17,6 +17,7 @@ library
     import: common
     hs-source-dirs: src
     exposed-modules:
+        Types
         Sources
         Functions
         ComputationM
diff --git a/byg/src/ComputationM.hs b/byg/src/ComputationM.hs
index b78ae23..c2deafc 100644
--- a/byg/src/ComputationM.hs
+++ b/byg/src/ComputationM.hs
@@ -1,17 +1,14 @@
 {-# LANGUAGE GADTs #-}
 module ComputationM where
 
+import Types
+import Sources
+import Functions
+
 import Unsafe.Coerce (unsafeCoerce)
 import Control.Monad.State
 import Control.Monad.Writer
 
-import Functions
-import Sources
-
-
-data ComputationRun a b = ComputationRun (Function a b)
-                        | ComputationRunIO (FunctionIO a b)
-
 
 
 data TypedRun a b where
@@ -77,6 +74,9 @@ runIO f input = genDependency (Dependency input (FIO f))
 
 listDirectory = runIO ListDirectory
 openImage = runIO OpenImage
+convertImage = runIO ConvertImage
+saveFile = runIO SaveFile
+runPandoc = runIO RunPandoc
 
 
 makeTraversable :: Token TokenNotTraversable [a] -> Token TokenTraversable (Token TokenNotTraversable a)
diff --git a/byg/src/Functions.hs b/byg/src/Functions.hs
index 9814068..0ca37a8 100644
--- a/byg/src/Functions.hs
+++ b/byg/src/Functions.hs
@@ -2,37 +2,34 @@
 {-# LANGUAGE FunctionalDependencies #-}
 module Functions where
 
+import Types
 import Sources
 
-data Image = Image
-  deriving (Show)
-data ImageConversion = ImageConversion
-  deriving (Show)
-
 data Function a b where
   IsImageFilename :: Function FilePath Bool
   ConvertedImageFilename :: Function FilePath FilePath
 
 deriving instance Show (Function a b)
 
-data FunctionIO a b where
-  ConvertImage :: FunctionIO (Image, ImageConversion) Image
-  Save :: FunctionIO (a, FilePath) ()
-  RunPandoc :: FunctionIO String String
-
-deriving instance Show (FunctionIO a b)
-
-
-
 class (SourceState a, Show f) => IsFIO f a b | f -> a b where
   runFIO :: f -> a -> IO b
 
-data ListDirectory = ListDirectory
-  deriving (Show)
+data ListDirectory = ListDirectory deriving (Show)
 instance IsFIO ListDirectory FilePath [FilePath] where
-  runFIO ListDirectory path = undefined
+  runFIO ListDirectory _path = undefined
 
-data OpenImage = OpenImage
-  deriving (Show)
+data OpenImage = OpenImage deriving (Show)
 instance IsFIO OpenImage FilePath Image where
-  runFIO OpenImage path = undefined
+  runFIO OpenImage _path = undefined
+
+data ConvertImage = ConvertImage deriving (Show)
+instance IsFIO ConvertImage Image Image where
+  runFIO ConvertImage _image = undefined
+
+data SaveFile = SaveFile deriving (Show)
+instance IsFIO SaveFile (String, FilePath) () where
+  runFIO SaveFile _source = undefined
+
+data RunPandoc = RunPandoc deriving (Show)
+instance IsFIO RunPandoc String String where
+  runFIO RunPandoc _source = undefined
diff --git a/byg/src/Sources.hs b/byg/src/Sources.hs
index 627586c..28a7fe8 100644
--- a/byg/src/Sources.hs
+++ b/byg/src/Sources.hs
@@ -1,5 +1,7 @@
 module Sources where
 
+import Types
+
 import Data.ByteString (ByteString)
 
 data Source a where
@@ -10,3 +12,9 @@ class SourceState a where
 
 instance SourceState FilePath where
   stateOfSource = undefined
+
+instance SourceState Image where
+  stateOfSource = undefined
+
+instance SourceState (String, FilePath) where
+  stateOfSource = undefined
diff --git a/byg/src/Types.hs b/byg/src/Types.hs
new file mode 100644
index 0000000..40ebc50
--- /dev/null
+++ b/byg/src/Types.hs
@@ -0,0 +1,4 @@
+module Types where
+
+data Image = Image
+  deriving (Show)