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Diffstat (limited to 'compiler/utils/Util.hs')
| -rw-r--r-- | compiler/utils/Util.hs | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/compiler/utils/Util.hs b/compiler/utils/Util.hs index 8cafbfb4f1..ff0f45f725 100644 --- a/compiler/utils/Util.hs +++ b/compiler/utils/Util.hs @@ -14,6 +14,8 @@ module Util ( zipEqual, zipWithEqual, zipWith3Equal, zipWith4Equal, zipLazy, stretchZipWith, zipWithAndUnzip, + zipWithLazy, zipWith3Lazy, + filterByList, filterByLists, partitionByList, unzipWith, @@ -322,6 +324,20 @@ zipLazy :: [a] -> [b] -> [(a,b)] zipLazy [] _ = [] zipLazy (x:xs) ~(y:ys) = (x,y) : zipLazy xs ys +-- | 'zipWithLazy' is like 'zipWith' but is lazy in the second list. +-- The length of the output is always the same as the length of the first +-- list. +zipWithLazy :: (a -> b -> c) -> [a] -> [b] -> [c] +zipWithLazy _ [] _ = [] +zipWithLazy f (a:as) ~(b:bs) = f a b : zipWithLazy f as bs + +-- | 'zipWith3Lazy' is like 'zipWith3' but is lazy in the second and third lists. +-- The length of the output is always the same as the length of the first +-- list. +zipWith3Lazy :: (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d] +zipWith3Lazy _ [] _ _ = [] +zipWith3Lazy f (a:as) ~(b:bs) ~(c:cs) = f a b c : zipWith3Lazy f as bs cs + -- | 'filterByList' takes a list of Bools and a list of some elements and -- filters out these elements for which the corresponding value in the list of -- Bools is False. This function does not check whether the lists have equal |