shithub: MicroHs

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Add more strict folds

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

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

@@ -4,7 +4,7 @@

   module Data.List_Type,

   (++), head, last, tail, init, uncons, unsnoc, singleton, null, length,

   map, reverse, intersperse, intercalate, transpose, subsequences, permutations,

-  foldl, foldl', foldl1, foldl1', foldr, foldr1,

+  foldl, foldl', foldl1, foldl1', foldr, foldr', foldr1, foldr1',

   concat, concatMap, and, or, any, all, sum, product, maximum, minimum,

   scanl, scanl', scanl1, scanr, scanr1,

   mapAccumL, mapAccumR,

@@ -106,13 +106,11 @@

     rec (x : xs) = f x (rec xs)

   in rec

-{-

 foldr' :: forall a b . (a -> b -> b) -> b -> [a] -> b

 foldr' f z [] = z

 foldr' f z (x:xs) =

   let y = foldr f z xs

   in  y `seq` f x y

--}

 foldr1 :: forall a . (a -> a -> a) -> [a] -> a

 foldr1 f =

@@ -120,6 +118,16 @@

     rec [] = error "foldr1"

     rec [x] = x

     rec (x : xs) = f x (rec xs)

+  in rec

+

+foldr1' :: forall a . (a -> a -> a) -> [a] -> a

+foldr1' f =

+  let

+    rec [] = error "foldr1"

+    rec [x] = x

+    rec (x : xs) =

+          let y = rec xs

+          in  y `seq` f x y

   in rec

 foldl :: forall a b . (b -> a -> b) -> b -> [a] -> b

-- 

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