shithub: MicroHs

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Slightly faster unzip

--- a/lib/Data/List.hs

+++ b/lib/Data/List.hs

@@ -185,6 +185,8 @@

 -- XXX not as lazy as it could be

 unzip :: forall a b . [(a, b)] -> ([a], [b])

+unzip xys = (map fst xys, map snd xys)  -- this version is slightly faster than the other two

+{-

 unzip axys =

   case axys of

     [] -> ([], [])

@@ -191,6 +193,13 @@

     (x,y) : xys ->

       case unzip xys of

         (xs, ys) -> (x:xs, y:ys)

+-}

+{-

+unzip [] = ([], [])

+unzip ((x,y) : xys) =

+  let (xs, ys) = unzip xys

+  in  (x:xs, y:ys)

+-}

 -- XXX not as lazy as it could be

 unzip3 :: forall a b c . [(a, b, c)] -> ([a], [b], [c])

-- 

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