refactoring

1 files changed, 6 insertions, 5 deletions

diff --git a/src/LambdaCube/Compiler/DeBruijn.hs b/src/LambdaCube/Compiler/DeBruijn.hs
index 8244a5d0..7d3e2679 100644
--- a/src/LambdaCube/Compiler/DeBruijn.hs
+++ b/src/LambdaCube/Compiler/DeBruijn.hs
@@ -76,7 +76,7 @@ freeVar :: Int -> FreeVars
 freeVar i = FreeVars $ 1 `shiftL` i
 
 delVar :: Int -> FreeVars -> FreeVars
-delVar i = appFreeVars i (`shiftR` 1)
+delVar l (FreeVars i) = FreeVars $ (i `shiftR` (l+1) `shiftL` l) .|. (i .&. ((1 `shiftL` l)-1))
 
 shiftFreeVars :: Int -> FreeVars -> FreeVars
 shiftFreeVars i (FreeVars x) = FreeVars $ x `shift` i
@@ -92,12 +92,13 @@ isClosed (FreeVars x) = x == 0
 
 lowerFreeVars = shiftFreeVars (-1)
 
-rearrangeFreeVars g l = appFreeVars l $ case g of
-    RFUp n -> (`shiftL` n)
-    RFMove n -> \x -> if testBit x n then (clearBit x n `shiftL` 1) `setBit` 0 else x `shiftL` 1
+rearrangeFreeVars g l (FreeVars i) = FreeVars $ case g of
+    RFUp n -> (i `shiftR` l `shiftL` (n+l)) .|. (i .&. ((1 `shiftL` l)-1))
+    RFMove n -> (f $ i `shiftR` l `shiftL` (l+1)) .|. (i .&. ((1 `shiftL` l)-1))
+      where
+        f x = if testBit x (n+l+1) then x `clearBit` (n+l+1) `setBit` l else x
     _ -> error $ "rearrangeFreeVars: " ++ show g
 
-appFreeVars l f (FreeVars i) = FreeVars $ (f (i `shiftR` l) `shiftL` l) .|. (i .&. (2^l-1))
 
 -- TODO: rename
 dbGE i (getFreeVars -> FreeVars x) = (x `shiftR` i) == 0