Eta reduction

src/Dodge/Item/Grammar.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE TupleSections #-}
 module Dodge.Item.Grammar (
     invLDT,
     invLDT',
@@ -152,8 +153,8 @@ itemToFunction itm = case itm ^. itType of
     CLICKER{} -> GadgetPlatformSF
     _ -> NoSF
 
-structureToPotentialFunction :: LDTree ItemLink CItem -> S.Set ItemStructuralFunction
-structureToPotentialFunction ldt = case ldt ^. ldtValue . _1 . itType of
+treeToPotentialFunction :: LDTree ItemLink CItem -> S.Set ItemStructuralFunction
+treeToPotentialFunction ldt = case ldt ^. ldtValue . _1 . itType of
     STICKYMOD -> S.singleton GrenadeHitEffectSF
     ATTACH GIMBAL -> S.singleton ProjectileStabiliserSF
     ATTACH GYROSCOPE -> S.singleton ProjectileStabiliserSF
@@ -169,18 +170,16 @@ type LDTComb a b = LDTree b a -> LDTree b a -> Maybe (LDTree b a)
 leftIsParentCombine :: LDTComb CItem ItemLink
 leftIsParentCombine ltree rtree = do
     let l = rightChildList ltree
-        xs = dropWhile ((\s -> not $ S.member s (structureToPotentialFunction rtree)) . fst) l
+        xs = dropWhile ((\s -> not $ S.member s (treeToPotentialFunction rtree)) . fst) l
     (sf,linktype) <- safeHead xs
-    return $
-        ltree & ldtRight .:~ (linktype, rtree & ldtValue . _2 .~ sf)
+    return $ ltree & ldtRight .:~ (linktype, rtree & ldtValue . _2 .~ sf)
 
 rightIsParentCombine :: LDTComb CItem ItemLink
 rightIsParentCombine ltree rtree = do
     let l = leftChildList rtree
-        xs = dropWhile ((\s -> not $ S.member s (structureToPotentialFunction ltree)) . fst) l
+        xs = dropWhile ((\s -> not $ S.member s (treeToPotentialFunction ltree)) . fst) l
     (sf,linktype) <- safeHead xs
-    return $
-        rtree & ldtLeft .:~ (linktype, ltree & ldtValue . _2 .~ sf)
+    return $ rtree & ldtLeft .:~ (linktype, ltree & ldtValue . _2 .~ sf)
 
 leftChildList :: LDTree ItemLink CItem -> [(ItemStructuralFunction, ItemLink)]
 leftChildList t = foldl' f l (reverse $ t ^.. ldtLeft . each . _1)
@@ -209,13 +208,20 @@ leftRightCombine f f' t1 t2 = f t1 t2 <|> checkdepth t1 t2
     checktop t t' = f' t t'
 
 joinItemsInList :: (a -> a -> Maybe a) -> [a] -> [a]
-joinItemsInList f xs = snd $ h (xs, [])
+joinItemsInList f = fst . h . ([],)
   where
-    h ([], zs) = ([], zs)
-    h (y : ys, []) = h (ys, [y])
-    h (y : ys, z : zs) = case f y z of
-        Nothing -> h (ys, y : z : zs)
-        Just w -> h (w : ys, zs)
+    h (zs, []) = (zs, [])
+    h ([],y : ys) = h ([y],ys)
+    h ( z : zs, y : ys) = case f y z of
+        Nothing -> h ( y : z : zs,ys)
+        Just w -> h ( zs,w : ys)
+--joinItemsInList f xs = snd $ h (xs, [])
+--  where
+--    h ([], zs) = ([], zs)
+--    h (y : ys, []) = h (ys, [y])
+--    h (y : ys, z : zs) = case f y z of
+--        Nothing -> h (ys, y : z : zs)
+--        Just w -> h (w : ys, zs)
 
 -- this puts the first elements in the intmap at the end of the list
 invLDT :: IM.IntMap Item -> [LDTree ItemLink CItem]