feat(third_party/bazel): Check in rules_haskell from Tweag r/17

1 files changed, 20 insertions, 0 deletions

diff --git a/third_party/bazel/rules_haskell/examples/vector/benchmarks/TestData/ParenTree.hs b/third_party/bazel/rules_haskell/examples/vector/benchmarks/TestData/ParenTree.hs
new file mode 100644
index 0000000000..4aeb750954
--- /dev/null
+++ b/third_party/bazel/rules_haskell/examples/vector/benchmarks/TestData/ParenTree.hs
@@ -0,0 +1,20 @@
+module TestData.ParenTree where
+
+import qualified Data.Vector.Unboxed as V
+
+parenTree :: Int -> (V.Vector Int, V.Vector Int)
+parenTree n = case go ([],[]) 0 (if even n then n else n+1) of
+               (ls,rs) -> (V.fromListN (length ls) (reverse ls),
+                           V.fromListN (length rs) (reverse rs))
+  where
+    go (ls,rs) i j = case j-i of
+                       0 -> (ls,rs)
+                       2 -> (ls',rs')
+                       d -> let k = ((d-2) `div` 4) * 2
+                            in
+                            go (go (ls',rs') (i+1) (i+1+k)) (i+1+k) (j-1)
+      where
+        ls' = i:ls
+        rs' = j-1:rs
+
+