Don't duplicate token ids in lists

byg/src/ComputationM.hs

@@ -38,8 +38,11 @@ newtype ComputationM' a = ComputationM { unComputationM :: WriterT [DependencyUn
 
 type ComputationM a = ComputationM' (Token a)
 
+evalComputationM' :: Int -> ComputationM () -> ([DependencyUntyped], Int)
+evalComputationM' top m = runState (execWriterT (unComputationM m)) top
+
 evalComputationM :: ComputationM () -> [DependencyUntyped]
-evalComputationM m = evalState (execWriterT (unComputationM m)) 0
+evalComputationM m = fst (evalComputationM' 0 m)
 
 genDependency :: (Show u, Show a) => (Token a -> Dependency u a) -> ComputationM a
 genDependency g = do
@@ -76,7 +79,11 @@ saveFile = runIO SaveFile
 runPandoc = runIO RunPandoc
 
 mapComputationM :: (Show a, Show b) => (Token a -> ComputationM b) -> Token [a] -> ComputationM [b]
-mapComputationM f input = genDependency (Dependency input (MapComp (evalComputationM m)))
+mapComputationM f input = do
+  top <- get
+  let (res, top') = evalComputationM' top m
+  put top'
+  genDependency (Dependency input (MapComp res))
   where m :: ComputationM ()
         m = do
           inp <- getListElem