1 files changed, 30 insertions, 0 deletions

diff --git a/lazy.hs b/lazy.hs
new file mode 100644
index 0000000..5bbfa51
--- /dev/null
+++ b/lazy.hs
@@ -0,0 +1,30 @@
+{-# LANGUAGE NoMonomorphismRestriction #-}
+import Control.Monad.ST
+import Control.Monad.ST.Unsafe
+import Data.VCDIFF
+import qualified Data.ByteString as B
+
+step2 = undefined
+
+step1 = do
+    xs <- unsafeInterleaveST $ step2
+    return $ 3 : xs
+
+test f = do
+    xs <- f $ step2
+    return $ 3 : xs
+
+test2 f = withByteString B.empty $ \_ _ -> do
+    xs <- f $ step2
+    return $ 3 : xs
+
+main = do
+    let xs = runST step1
+        ys = runST (test id)
+        zs = runST (test unsafeInterleaveST)
+        vs = runST (test2 unsafeInterleaveST)
+    print $ take 1 xs
+    -- print $ take 1 ys
+    print $ take 1 zs
+    print $ take 1 vs
+