diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,26 @@
+Copyright (c) 2012, Michael Snoyman
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/cabal-nirvana.cabal b/cabal-nirvana.cabal
new file mode 100644
--- /dev/null
+++ b/cabal-nirvana.cabal
@@ -0,0 +1,33 @@
+Name:                cabal-nirvana
+Version:             0.1
+Synopsis:            Avoid Cabal dependency hell by constraining to known good versions.
+Description:         This tool takes a list of known compatible versions of libraries and forces them to be used, via constraints in your cabal config file. This should bypass a lot of cabal dependency hell, thereby inducing nirvana.
+Homepage:            http://github.com/snoyberg/cabal-nirvana
+License:             BSD3
+License-file:        LICENSE
+Author:              Michael Snoyman
+Maintainer:          michael@snoyman.com
+Category:            Distribution
+Build-type:          Simple
+Cabal-version:       >=1.2
+
+flag generate
+    default: False
+
+Executable cabal-nirvana
+  Main-is:             cabal-nirvana.hs
+  Build-depends:       base < 5
+                     , HTTP
+                     , process
+                     , directory
+
+Executable cabal-nirvana-generate
+  Main-is:             generate.hs
+  if flag(generate)
+    Buildable: True
+  else
+    Buildable: False
+  Build-depends:       Cabal
+                     , containers
+                     , transformers
+                     , packdeps >= 0.3 && < 0.4
diff --git a/cabal-nirvana.hs b/cabal-nirvana.hs
new file mode 100644
--- /dev/null
+++ b/cabal-nirvana.hs
@@ -0,0 +1,111 @@
+import System.Environment (getArgs)
+import System.Directory (getAppUserDataDirectory)
+import Control.Applicative ((<$>))
+import Data.Maybe (catMaybes)
+import Data.Char (isSpace)
+import Data.List (isPrefixOf, foldl')
+import System.Exit (exitWith)
+import System.Cmd (rawSystem)
+import Network.HTTP (simpleHTTP, getRequest, getResponseBody)
+
+configFile :: IO FilePath
+configFile = do
+    dir <- getAppUserDataDirectory "cabal"
+    return $ dir ++ "/config"
+
+nirvanaFile :: IO FilePath
+nirvanaFile = do
+    dir <- getAppUserDataDirectory "cabal-nirvana"
+    return $ dir ++ "/default"
+
+data Package = Package
+    { name :: String
+    , version :: String
+    }
+
+readPackages :: FilePath -> IO [Package]
+readPackages fp =
+    readFile fp >>= (catMaybes <$>) . mapM parse . lines
+  where
+    parse s
+        | all isSpace s = return Nothing
+        | "--" `isPrefixOf` s = return Nothing
+    parse s =
+        case words s of
+            [a, b] -> return $ Just $ Package a b
+            _ -> error $ "Invalid nirvana line: " ++ show s
+
+readConfigFile :: IO [String]
+readConfigFile = do
+    ls <- lines <$> (configFile >>= readFile)
+    -- force evaluation
+    if length ls > 0
+        then return ls
+        else return []
+
+writeConfigFile :: [String] -> IO ()
+writeConfigFile ss = configFile >>= flip writeFile (unlines ss)
+
+main :: IO ()
+main = do
+    args <- getArgs
+    case args of
+        ("fetch":rest) -> do
+            url <-
+                case rest of
+                    [] -> return "http://www.snoyman.com/cabal-nirvana/yesod"
+                    [x] -> return x
+                    _ -> error $ "Usage: cabal-nirvana fetch [URL]"
+            str <- simpleHTTP (getRequest url) >>= getResponseBody
+            nirvanaFile >>= flip writeFile str
+        ("start":rest) -> do
+            fp <-
+                case rest of
+                    [] -> nirvanaFile
+                    [x] -> return x
+                    _ -> error $ "Usage: cabal-nirvana start [package file]"
+            packages <- readPackages fp
+            config <- readConfigFile
+            writeConfigFile $ addNirvana packages $ removeNirvana config
+        ["stop"] -> do
+            config <- readConfigFile
+            writeConfigFile $ removeNirvana config
+        ("test":rest) -> do
+            fp <-
+                case rest of
+                    [] -> nirvanaFile
+                    [x] -> return x
+                    _ -> error $ "Usage: cabal-nirvana test [package file]"
+            packages <- readPackages fp
+            let ws = map (\(Package n v) -> concat [n, "-", v]) packages
+            putStrLn $ "cabal-dev install " ++ unwords ws
+            ec <- rawSystem "cabal-dev" $ "install" : ws
+            exitWith ec
+        _ -> do
+            putStrLn "Available commands:"
+            putStrLn "    cabal-nirvana fetch [URL]"
+            putStrLn "    cabal-nirvana start [package file]"
+            putStrLn "    cabal-nirvana stop"
+            putStrLn "    cabal-nirvana test [package file]"
+
+beginLine, endLine :: String
+beginLine = "-- cabal-nirvana begin"
+endLine = "-- cabal-nirvana end"
+
+removeNirvana :: [String] -> [String]
+removeNirvana [] = []
+removeNirvana (x:xs)
+    | x == beginLine = removeNirvana $ drop 1 $ dropWhile (/= endLine) xs
+    | otherwise = x : removeNirvana xs
+
+addNirvana :: [Package] -> [String] -> [String]
+addNirvana ps =
+    (++ ss)
+  where
+    ss = beginLine : foldr (:) [endLine] (map toS ps)
+    toS (Package n v) = concat
+        [ "constraint: "
+        , n
+        , " == "
+        , v
+        ]
diff --git a/generate.hs b/generate.hs
new file mode 100644
--- /dev/null
+++ b/generate.hs
@@ -0,0 +1,44 @@
+import Distribution.PackDeps
+import System.Environment (getArgs)
+import Control.Monad.Trans.RWS
+import Control.Monad.IO.Class (liftIO)
+import qualified Data.Set as Set
+import qualified Data.Map as Map
+import Control.Monad (unless)
+import System.IO (hPutStrLn, stderr)
+import Distribution.Text (display)
+import Distribution.Package (Dependency (..), PackageName (..))
+
+data Package = Package
+    { name :: String
+    , version :: String
+    }
+    deriving (Eq, Ord)
+
+type M = RWST Newest (Set.Set Package) (Set.Set String) IO
+
+bootlibs :: Set.Set String
+bootlibs = Set.fromList $ words
+    "containers ghc-binary ghc-prim Cabal base old-locale old-time time random syb template-haskell filepath haskell98 unix Win32 bytestring deepseq array network process directory" -- FIXME
+
+main :: IO ()
+main = do
+    toProcess <- getArgs
+    newest <- loadNewest
+    ((), _, packages) <- runRWST (mapM_ process toProcess) newest bootlibs
+    mapM_ (\(Package n v) -> putStrLn $ unwords [n, v]) $ Set.toList packages
+
+process :: String -> M ()
+process package = do
+    processed <- get
+    unless (package `Set.member` processed) $ do
+        put $ Set.insert package processed
+        newest <- ask
+        case Map.lookup package newest of
+            Nothing -> liftIO $ hPutStrLn stderr $ "Warning: Unknown package: " ++ package
+            Just (PackInfo version mdi _) -> do
+                tell $ Set.singleton $ Package package $ display version
+                case mdi of
+                    Nothing -> liftIO $ hPutStrLn stderr $ "Warning: No information on: " ++ package
+                    Just (DescInfo { diDeps = deps }) ->
+                        mapM_ (\(Dependency (PackageName n) _) -> process n) deps