add for-loops.hs

for-loops.hs

@@ -0,0 +1,35 @@
+import Data.Foldable (for_)
+import Data.Traversable (for)
+
+import Control.Monad (when)
+
+main =
+  do
+    putStr "Numbers:"
+    for_ [1..5] $ \i ->
+      do
+        putStr " "
+        putStr (show i)
+    putStr "\n"
+
+    putStr "Odds:"
+    for_ [1..5] $ \i ->
+        when (odd i) $
+          do
+            putStr " "
+            putStr (show i)
+    putStr "\n"
+
+    putStr "Odds:"
+    for_ (filter odd [1..5]) $ \i ->
+      do
+        putStr " "
+        putStr (show i)
+    putStr "\n"
+
+    tens <-
+      for [1..3] $ \i ->
+        do
+          putStr (show i ++ " ")
+          return (i * 10)
+    putStr ("(sum: " ++ show (sum tens) ++ ")\n")

outputs/for-loops.txt

@@ -0,0 +1,4 @@
+Numbers: 1 2 3 4 5
+Odds: 1 3 5
+Odds: 1 3 5
+1 2 3 (sum: 60)

tools/outputs.nix

@@ -20,6 +20,7 @@ in
     (run "common-types.txt" ../common-types.hs)
     (run "hashing.txt" ../hashing.hs)
     (run "hello-world.txt" ../hello-world.hs)
+    (run "for-loops.txt" ../for-loops.hs)
     (run "threads.txt" ../threads.hs)
     (run "variables.txt" ../variables.hs)
   ]