1 files changed, 1 insertions, 57 deletions
diff --git a/app/Code.hs b/app/Code.hs
index 4473287..684686f 100644
--- a/app/Code.hs
+++ b/app/Code.hs
@@ -23,7 +23,7 @@ data Instr
   | Invoke Builtin -- give control to a builtin (invoked from head)
   | Done -- all done, can return
   | Cut -- remove choicepoints of the current goal
-  | Choices [[Code]] -- split off several possibilities (push choicepoints)
+  | Choices [Code] -- split off several possibilities (push choicepoints)
   deriving (Show)
 
 type Code = [Instr]
@@ -77,59 +77,3 @@ data Builtin =
 
 instance Show Builtin where
   show _ = "Builtin _"
-
-data Dereferenced
-  = FreeRef Int
-  | BoundRef Int Datum
-  | NoRef
-  deriving (Show, Eq)
-
--- TRICKY: HeapRefs alone must not form a cycle other than the FreeRef case.
-derefHeap :: Heap -> Int -> Dereferenced
-derefHeap h@(Heap _ hmap) x =
-  case hmap M.!? x of
-    Just (HeapRef x') ->
-      if x == x'
-        then FreeRef x'
-        else derefHeap h x'
-    Just x' -> BoundRef x x'
-    _ -> NoRef
-
-writeHeap :: Int -> Datum -> Heap -> Heap
-writeHeap addr x (Heap nxt m) = Heap nxt (M.adjust (const x) addr m)
-
-newHeapVar :: Heap -> (Heap, Int)
-newHeapVar heap = head <$> newHeapVars 1 heap
-
-newHeapVars :: Int -> Heap -> (Heap, [Int])
-newHeapVars n (Heap nxt m) =
-  let addrs = [nxt + i - 1 | i <- [1 .. n]]
-   in ( Heap (nxt + n) $
-        foldr (uncurry M.insert) m [(a, HeapRef a) | a <- addrs]
-      , addrs)
-
-withNewHeapStruct :: Int -> Datum -> Heap -> ([Datum] -> Heap -> a) -> a
-withNewHeapStruct addr s@(Struct Id {arity = arity}) heap cont =
-  let (Heap nxt' m', addrs) = newHeapVars (arity + 1) heap
-      m'' = M.insert addr (HeapRef $ head addrs) . M.insert (head addrs) s $ m'
-   in cont (map HeapRef $ tail addrs) (Heap nxt' m'')
-
-heapStruct ::
-     Monad m
-  => (Datum -> m a)
-  -> (Datum -> [a] -> m a)
-  -> (Datum -> Int -> m a)
-  -> Heap
-  -> Int
-  -> m a
-heapStruct atom struct rec (Heap _ heap) hr = go [hr] hr
-  where
-    go visited ref
-      | rr@(HeapRef r) <- heap M.! ref =
-        if r == ref || r `elem` visited
-          then rec rr ref
-          else go (r : visited) r
-      | s@(Struct (IR.Id _ arity)) <- heap M.! ref =
-        sequence [go (ref + i : visited) (ref + i) | i <- [1 .. arity]] >>=
-        struct s
-      | x <- heap M.! ref = atom x