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--- codesnippets:accumulatingwithinmonadiccontextswithoutfolds [2022/05/28 16:08] – created f2b216
+++ codesnippets:accumulatingwithinmonadiccontextswithoutfolds [2025/10/08 00:48] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-~~ DISCUSSION ~~
 ====== Accumulating within monadic contexts without folds ======
+  * <code Haskell>
+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+{-# HLINT ignore "Use void" #-}
+{-# HLINT ignore "Use map" #-}
+{-# HLINT ignore "Use foldl" #-}
+main :: IO ()
+main =
+    do
+        print (f1a [3, 2, 6, 8])
+        f1b [3, 2, 6, 8]
+        f1c [3, 2, 6, 8] >>= print >> return ()
+        print (f2a [] [3, 2, 6, 8])
+        f2b [3, 2, 6, 8]
+        f2c [] [3, 2, 6, 8] >> return ()
+f1a :: [Int] -> [Int]
+f1a [] = []
+f1a (n:rln) = (n + 1) : f1a rln
+f1b :: [Int] -> IO ()
+f1b ln = f1' ln >>= print
+    where
+        f1' :: [Int] -> IO [Int]
+        f1' [] = return []
+        f1' (n:rln) = f1' rln >>= (\r -> return ((n + 1) : r))
+f1c :: [Int] -> IO [Int]
+f1c [] = return []
+f1c (n:rln) = f1c rln >>= (\r -> return ((n + 1) : r))
+f2a :: [Int] -> [Int] -> [Int]
+f2a lnAccu [] = lnAccu
+f2a lnAccu (n:rln) = f2a (n + 1 : lnAccu) rln
+f2b :: [Int] -> IO ()
+f2b ln = f2b' [] ln >>= print
+    where
+        f2b' :: [Int] -> [Int] -> IO [Int]
+        f2b' lnAccu [] = return lnAccu
+        f2b' lnAccu (n:rln) = f2b' ((n + 1) : lnAccu) rln
+f2c :: [Int] -> [Int] -> IO [Int]
+f2c lnAccu [] = print lnAccu >> return lnAccu
+f2c lnAccu (n:rln) = f2c ((n + 1) : lnAccu) rln
+</code>
+===== ✎ =====
+~~DISCUSSION~~