Compact Regions

This brings in initial support for compact regions, as described in the
ICFP 2015 paper "Efficient Communication and Collection with Compact
Normal Forms" (Edward Z. Yang et.al.) and implemented by Giovanni
Campagna.

Some things may change before the 8.2 release, but I (Simon M.) wanted
to get the main patch committed so that we can iterate.

What documentation there is is in the Data.Compact module in the new
compact package.  We'll need to extend and polish the documentation
before the release.

Test Plan:
validate
(new test cases included)

Reviewers: ezyang, simonmar, hvr, bgamari, austin

Subscribers: vikraman, Yuras, RyanGlScott, qnikst, mboes, facundominguez, rrnewton, thomie, erikd

Differential Revision: https://phabricator.haskell.org/D1264

GHC Trac Issues: #11493

1 files changed, 35 insertions, 0 deletions

diff --git a/libraries/compact/tests/compact_simple.hs b/libraries/compact/tests/compact_simple.hs
new file mode 100644
index 0000000000..c4cfbbd151
--- /dev/null
+++ b/libraries/compact/tests/compact_simple.hs
@@ -0,0 +1,35 @@
+module Main where
+
+import Control.Exception
+import System.Mem
+
+import Data.Compact
+
+assertFail :: String -> IO ()
+assertFail msg = throwIO $ AssertionFailed msg
+
+assertEquals :: (Eq a, Show a) => a -> a -> IO ()
+assertEquals expected actual =
+  if expected == actual then return ()
+  else assertFail $ "expected " ++ (show expected)
+       ++ ", got " ++ (show actual)
+
+-- test :: (Word -> a -> IO (Maybe (Compact a))) -> IO ()
+test func = do
+  let val = ("hello", 1, 42, 42, Just 42) ::
+        (String, Int, Int, Integer, Maybe Int)
+  str <- func 4096 val
+
+  -- check that val is still good
+  assertEquals ("hello", 1, 42, 42, Just 42) val
+  -- check the value in the compact
+  assertEquals ("hello", 1, 42, 42, Just 42) (getCompact str)
+  performMajorGC
+  -- check again val
+  assertEquals ("hello", 1, 42, 42, Just 42) val
+  -- check again the value in the compact
+  assertEquals ("hello", 1, 42, 42, Just 42) (getCompact str)
+
+main = do
+  test newCompact
+  test newCompactNoShare