filterByPredicate

lab4/app/Main.hs

@@ -7,3 +7,8 @@ main = do
   putStrLn $ "Примеры работы `isCongruent`"
   putStrLn $ "isCongruent 10 12 2: " ++ show (isCongruent 10 12 2)
   putStrLn $ "isCongruent 10 11 2: " ++ show (isCongruent 10 11 2)
+
+  putStrLn $ "\nПример работы `filterByPredicate`"
+  let predicate x = x > 5
+  putStrLn $ "filterByPredicate (>5) [1, 6, 3, 7, 2]: " 
+    ++ show (filterByPredicate predicate [1 :: Int, 6, 3, 7, 2])

lab4/src/Lib.hs

@@ -1,6 +1,16 @@
 module Lib
-    ( isCongruent
+    ( isCongruent,
+      filterByPredicate
     ) where
 
 isCongruent :: Int -> Int -> Int -> Bool
 isCongruent a b d = a `mod` d == b `mod` d
+
+
+filterByPredicate :: (a -> Bool) -> [a] -> [a]
+filterByPredicate _ [] = []
+filterByPredicate predicate (x:xs) 
+    | predicate x = x : filteredTail
+    | otherwise = filteredTail
+    where
+        filteredTail = filterByPredicate predicate xs