Split out the foldr example

「BangPattern をつけてはいけないところは， Strict 拡張でも lazy を明示的に指定しなくてはいけないので，ここら辺も NoStrict の時と注意点が同じと言う感じですね」の例としてfoldrの例を分ける

Author: igrep

examples/strict-gotchas/stackoverflow-foldl.hs

@@ -0,0 +1,16 @@
+{-
+  stack exec ghc -- -O0 -rtsopts -with-rtsopts=-K1k          ./stackoverflow.hs
+  stack exec ghc -- -O0 -rtsopts -with-rtsopts=-K1k -XStrict ./stackoverflow.hs
+  stack exec ghc -- -O1 -rtsopts -with-rtsopts=-K1k          ./stackoverflow.hs
+  stack exec ghc -- -O1 -rtsopts -with-rtsopts=-K1k -XStrict ./stackoverflow.hs
+-}
+
+import Control.Exception
+import Data.List
+
+main :: IO ()
+main = do
+  let size = 5000
+  putStrLn "BEGIN"
+  evaluate $ foldl (\z x -> x : z) [] [1 .. size]
+  putStrLn "DONE"

examples/strict-gotchas/stackoverflow.hs …es/strict-gotchas/stackoverflow-foldr.hsexamples/strict-gotchas/stackoverflow.hs renamed to examples/strict-gotchas/stackoverflow-foldr.hs examples/strict-gotchas/stackoverflow.hs renamed to examples/strict-gotchas/stackoverflow-foldr.hs

@@ -16,8 +16,5 @@ main = do
   evaluate $ foldr (:) [] [1 .. size]
   putStrLn "DONE: foldr 1"
 
-  evaluate $ foldl (\z x -> x : z) [] [1 .. size]
-  putStrLn "DONE: foldl"
-
   evaluate $ foldr (\x z -> x : z) [] [1 .. size]
   putStrLn "DONE: foldr 2"