Removed 'group' function, updated rotl and rotr to work for empty vectors

[matthijs/master-project/support/tfvec.git] / Data / Param / TFVec.hs

diff --git a/Data/Param/TFVec.hs b/Data/Param/TFVec.hs
index 50b2fda258b44de6c285aeacae5889aeeddd5ab9..87838930a20542d6d5d5682df6a26b8ec525dd71 100644 (file)
--- a/Data/Param/TFVec.hs
+++ b/Data/Param/TFVec.hs
@@ -35,7 +35,6 @@ module Data.Param.TFVec
   , take
   , drop
   , select
---  , group
   , (<+)
   , (++)
   , map
@@ -175,13 +174,6 @@ select f s n = liftV (select' f' s' n')
           | otherwise = []
         selectFirst0 _ 0 [] = []
 
--- group :: PositiveT n => n -> TFVec s a -> TFVec (Div s n) (TFVec n a)
--- group n = liftV (group' (fromIntegerT n))
---   where group' :: Int -> [a] -> [TFVec s a]
---         group' n xs = case splitAtM n xs of
---                         Nothing -> []
---                         Just (ls, rs) -> TFVec ls : group' n rs
-
 (<+) :: TFVec s a -> a -> TFVec (Succ s) a
 (<+) (TFVec xs) x = TFVec (xs P.++ [x])
 
@@ -217,11 +209,18 @@ shiftr :: (PositiveT s, NaturalT n, n ~ Pred s, s ~ Succ n) =>
           TFVec s a -> a -> TFVec s a
 shiftr xs x = tail xs <+ x
   
-rotl :: (PositiveT s, s ~ Succ (Pred s)) => TFVec s a -> TFVec s a
-rotl xs = last xs +> init xs
-
-rotr :: (PositiveT s, s ~ Succ (Pred s)) => TFVec s a -> TFVec s a
-rotr xs = tail xs <+ head xs
+rotl :: forall s a . NaturalT s => TFVec s a -> TFVec s a
+rotl = liftV rotl'
+  where vlen = fromIntegerT (undefined :: s)
+        rotl' [] = []
+        rotl' xs = let (i,[l]) = splitAt (vlen - 1) xs
+                   in l : i 
+
+rotr :: NaturalT s => TFVec s a -> TFVec s a
+rotr = liftV rotr'
+  where
+    rotr' [] = []
+    rotr' (x:xs) = xs P.++ [x] 
 
 concat :: TFVec s1 (TFVec s2 a) -> TFVec (s1 :*: s2) a
 concat = liftV (P.foldr ((P.++).unTFVec) [])