diff --git a/generation/Main.hs b/generation/Main.hs
index 7b40ae4..f0b3af2 100644
--- a/generation/Main.hs
+++ b/generation/Main.hs
@@ -13,11 +13,11 @@ import CryptoNum(cryptoNum)
 import Control.Monad(forM_,unless)
 import Data.Text.Lazy(Text, pack)
 import Division(divisionOps)
-import File(File,Task(..),generateTasks)
 import GHC.Conc(getNumCapabilities)
 import ModInv(generateModInvOps)
 import ModOps(modulusOps)
 import Multiply(safeMultiplyOps, unsafeMultiplyOps)
+import RustModule(RustModule,Task(..),generateTasks)
 import Scale(safeScaleOps, unsafeScaleOps)
 import Shift(shiftOps, signedShiftOps)
 import Signed(signedBaseOps)
@@ -39,7 +39,7 @@ highestBitsize = 512
 bitsizes :: [Word]
 bitsizes = [lowestBitsize,lowestBitsize+64..highestBitsize]
 
-unsignedFiles :: [File]
+unsignedFiles :: [RustModule]
 unsignedFiles = [
     base
   , binaryOps
@@ -60,7 +60,7 @@ unsignedFiles = [
   , unsafeSubtractOps
   ]
 
-signedFiles :: [File]
+signedFiles :: [RustModule]
 signedFiles = [
     safeSignedAddOps
   , safeSignedSubtractOps
@@ -72,7 +72,7 @@ signedFiles = [
   , unsafeSignedSubtractOps
   ]
 
-allFiles :: [File]
+allFiles :: [RustModule]
 allFiles = unsignedFiles ++ signedFiles
 
 printLast :: Progress String -> Timing -> Text
diff --git a/generation/generation.cabal b/generation/generation.cabal
index 01b8929..f064665 100644
--- a/generation/generation.cabal
+++ b/generation/generation.cabal
@@ -37,13 +37,13 @@ library
                        Conversions,
                        CryptoNum,
                        Division,
-                       File,
                        Gen,
                        Generators,
                        Karatsuba,
                        ModInv,
                        ModOps,
                        Multiply,
+                       RustModule,
                        Scale,
                        Shift,
                        Signed,
diff --git a/generation/src/Add.hs b/generation/src/Add.hs
index dc3ffe0..522b343 100644
--- a/generation/src/Add.hs
+++ b/generation/src/Add.hs
@@ -10,7 +10,6 @@ module Add(
 import Data.Bits((.&.))
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen(toLit)
 import Generators
 import Language.Rust.Data.Ident
@@ -19,11 +18,12 @@ import Language.Rust.Quote
 import Language.Rust.Syntax
 import System.Random(RandomGen)
 
+import RustModule
 numTestCases :: Int
 numTestCases = 3000
 
-safeAddOps :: File
-safeAddOps = File {
+safeAddOps :: RustModule
+safeAddOps = RustModule {
     predicate = \ me others -> (me + 64) `elem` others,
     outputName = "safe_add",
     isUnsigned = True,
@@ -31,8 +31,8 @@ safeAddOps = File {
     testCase = Just generateSafeTests
 }
 
-unsafeAddOps :: File
-unsafeAddOps = File {
+unsafeAddOps :: RustModule
+unsafeAddOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "unsafe_add",
     isUnsigned = True,
@@ -40,8 +40,8 @@ unsafeAddOps = File {
     testCase = Just generateUnsafeTests
 }
 
-safeSignedAddOps :: File
-safeSignedAddOps = File {
+safeSignedAddOps :: RustModule
+safeSignedAddOps = RustModule {
     predicate = \ me others -> (me + 64) `elem` others,
     outputName = "safe_sadd",
     isUnsigned = False,
@@ -49,8 +49,8 @@ safeSignedAddOps = File {
     testCase = Just generateSafeSignedTests
 }
 
-unsafeSignedAddOps :: File
-unsafeSignedAddOps = File {
+unsafeSignedAddOps :: RustModule
+unsafeSignedAddOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "unsafe_sadd",
     isUnsigned = False,
diff --git a/generation/src/Base.hs b/generation/src/Base.hs
index 05ea1a6..404dada 100644
--- a/generation/src/Base.hs
+++ b/generation/src/Base.hs
@@ -4,14 +4,14 @@ module Base(
   )
  where
 
-import File
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 
-base :: File
-base = File {
+base :: RustModule
+base = RustModule {
   predicate = \ _ _ -> True,
   outputName = "base",
   isUnsigned = True,
diff --git a/generation/src/BinaryOps.hs b/generation/src/BinaryOps.hs
index 46a405e..044483f 100644
--- a/generation/src/BinaryOps.hs
+++ b/generation/src/BinaryOps.hs
@@ -7,20 +7,20 @@ module BinaryOps(
 import Data.Bits(xor,(.&.),(.|.))
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen(toLit)
 import Generators
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-binaryOps :: File
-binaryOps = File {
+binaryOps :: RustModule
+binaryOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "binary",
     isUnsigned = True,
diff --git a/generation/src/Compare.hs b/generation/src/Compare.hs
index 8ddc915..5c9a5a1 100644
--- a/generation/src/Compare.hs
+++ b/generation/src/Compare.hs
@@ -4,19 +4,19 @@ module Compare(comparisons, signedComparisons)
 
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Generators
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-comparisons :: File
-comparisons = File {
+comparisons :: RustModule
+comparisons = RustModule {
   predicate = \ _ _ -> True,
   outputName = "compare",
   isUnsigned = True,
@@ -24,8 +24,8 @@ comparisons = File {
   testCase = Just generateTests
 }
 
-signedComparisons :: File
-signedComparisons = File {
+signedComparisons :: RustModule
+signedComparisons = RustModule {
   predicate = \ _ _ -> True,
   outputName = "scompare",
   isUnsigned = False,
diff --git a/generation/src/Conversions.hs b/generation/src/Conversions.hs
index 3871f77..b776a77 100644
--- a/generation/src/Conversions.hs
+++ b/generation/src/Conversions.hs
@@ -5,15 +5,15 @@ module Conversions(
   )
  where
 
-import File
 import Gen(toLit)
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 
-conversions :: File
-conversions = File {
+conversions :: RustModule
+conversions = RustModule {
   predicate = \ _ _ -> True,
   outputName = "conversions",
   isUnsigned = True,
@@ -21,8 +21,8 @@ conversions = File {
   testCase = Nothing
 }
 
-signedConversions :: File
-signedConversions = File {
+signedConversions :: RustModule
+signedConversions = RustModule {
   predicate = \ _ _ -> True,
   outputName = "sconversions",
   isUnsigned = False,
diff --git a/generation/src/CryptoNum.hs b/generation/src/CryptoNum.hs
index 59e8796..40905bc 100644
--- a/generation/src/CryptoNum.hs
+++ b/generation/src/CryptoNum.hs
@@ -7,20 +7,20 @@ module CryptoNum(
 import Data.Bits(testBit)
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen
 import Generators
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-cryptoNum :: File
-cryptoNum = File {
+cryptoNum :: RustModule
+cryptoNum = RustModule {
   predicate = \ _ _ -> True,
   outputName = "cryptonum",
   isUnsigned = True,
diff --git a/generation/src/Division.hs b/generation/src/Division.hs
index d5c1878..31688e3 100644
--- a/generation/src/Division.hs
+++ b/generation/src/Division.hs
@@ -4,20 +4,20 @@ module Division(divisionOps)
 
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen(toLit)
 import Generators
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-divisionOps :: File
-divisionOps = File {
+divisionOps :: RustModule
+divisionOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "divmod",
     isUnsigned = True,
diff --git a/generation/src/File.hs b/generation/src/File.hs
deleted file mode 100644
index f57d14f..0000000
--- a/generation/src/File.hs
+++ /dev/null
@@ -1,136 +0,0 @@
-{-# LANGUAGE QuasiQuotes #-}
-{-# LANGUAGE RankNTypes  #-}
-module File(
-         File(..),
-         Task(..),
-         generateTasks,
-         testFile
-       )
- where
-
-import Control.Monad(forM_)
-import Data.Char(toUpper)
-import Data.List(isPrefixOf)
-import Data.Map.Strict(Map)
-import qualified Data.Map.Strict as Map
-import Language.Rust.Data.Ident(mkIdent)
-import Language.Rust.Data.Position(Span)
-import Language.Rust.Pretty(writeSourceFile)
-import Language.Rust.Quote(item,sourceFile)
-import Language.Rust.Syntax(SourceFile)
-import System.FilePath(dropExtension,splitFileName,takeFileName,(</>))
-import System.IO(Handle,hPutStrLn)
-import System.Random(RandomGen(..))
-
-data File = File {
-    predicate :: Word -> [Word] -> Bool,
-    outputName :: FilePath,
-    isUnsigned :: Bool,
-    generator :: Word -> [Word] -> SourceFile Span,
-    testCase :: forall g. RandomGen g => Maybe (Word -> g -> [Map String String])
-}
-
-data Task = Task {
-    outputFile :: FilePath,
-    writer :: Handle -> IO ()
-}
-
-testFile :: Bool -> Word -> FilePath
-testFile True  size = "U" ++ show5 size ++ ".test"
-testFile False size = "I" ++ show5 size ++ ".test"
-
-show5 :: Word -> String
-show5 = go . show
- where
-  go x | length x < 5 = go ('0' : x)
-       | otherwise    = x
-
-generateTasks :: RandomGen g => g -> [File] -> [Word] -> [Task]
-generateTasks rng files sizes = basicTasks ++ moduleTasks
- where
-  basicTasks = go rng files sizes
-  moduleTasks = generateModules basicTasks
-  --
-  go :: RandomGen g => g -> [File] -> [Word] -> [Task]
-  go _ []             _  = []
-  go g (_:rest)       [] = go g rest sizes
-  go g files'@(file:_) (size:rest)
-    | not (predicate file size sizes) = go g files' rest
-    | otherwise =
-        let (myg, theirg) = split g
-            tasks = go theirg files' rest
-            (signedBit, prefix) | isUnsigned file = ("unsigned", "u")
-                                | otherwise       = ("signed", "i")
-            mainTask = Task {
-              outputFile = "src" </> signedBit </> (prefix ++ show size) </>
-                           outputName file ++ ".rs",
-              writer = \ hndl -> writeSourceFile hndl (generator file size sizes)
-            }
-        in case testCase file of
-             Nothing ->
-               mainTask : tasks
-             Just caseGenerator ->
-               let testTask = Task {
-                     outputFile = "testdata" </> outputName file </> testFile (isUnsigned file) size,
-                     writer = \ hndl -> writeTestCase hndl (caseGenerator size myg)
-                   }
-               in testTask : mainTask : tasks
-
-generateModules :: [Task] -> [Task]
-generateModules tasks = Map.foldrWithKey maddModule [] fileMap ++ [signedTask, unsignedTask]
- where
-  maddModule path mods acc
-   | ("src/unsigned" `isPrefixOf` path) || ("src/signed" `isPrefixOf` path) =
-        let (basePath, lowerName) = splitFileName (init path)
-            upperName = map toUpper lowerName
-            task = Task {
-              outputFile = basePath </> lowerName ++ ".rs",
-              writer = \ hndl ->
-                do forM_ mods $ \ modl ->
-                     hPutStrLn hndl ("mod " ++ modl ++ ";")
-                   hPutStrLn hndl ("pub use base::" ++ upperName ++ ";")
-            }
-        in task : acc
-   | otherwise =
-        acc
-  fileMap = foldr buildBaseMap Map.empty tasks
-  buildBaseMap task acc =
-    let (dir, fileext) = splitFileName (outputFile task)
-        file = dropExtension fileext
-    in Map.insertWith (++) dir [file] acc
-  --
-  signedTask = moduleTask "signed"
-  unsignedTask = moduleTask "unsigned"
-  moduleTask kind =
-    let mods = Map.foldrWithKey (topModule kind) [] fileMap
-        pubuses = Map.foldrWithKey (pubUse kind) [] fileMap
-    in Task {
-         outputFile = "src" </> (kind ++ ".rs"),
-         writer = \ hndl ->
-           writeSourceFile hndl [sourceFile|
-             $@{mods}
-             $@{pubuses}
-          |]
-       }
-  topModule kind path _ acc
-   | ("src/" ++ kind) `isPrefixOf` path =
-        let lowerName = takeFileName (init path)
-            modl = mkIdent lowerName
-        in [item| mod $$modl; |] : acc
-   | otherwise =
-        acc
-  pubUse kind path _ acc
-   | ("src/" ++ kind) `isPrefixOf` path =
-        let lowerName = takeFileName (init path)
-            tname = mkIdent (map toUpper lowerName)
-            modl = mkIdent lowerName
-        in [item| pub use $$modl::$$tname; |] : acc
-   | otherwise =
-        acc
-
-
-writeTestCase :: Handle -> [Map String String] -> IO ()
-writeTestCase hndl tests =
-  forM_ tests $ \ test ->
-    forM_ (Map.toList test) $ \ (key, value) ->
-      hPutStrLn hndl (key ++ ": " ++ value)
diff --git a/generation/src/ModInv.hs b/generation/src/ModInv.hs
index 2fffd76..b1f6ae5 100644
--- a/generation/src/ModInv.hs
+++ b/generation/src/ModInv.hs
@@ -8,20 +8,20 @@ module ModInv(
 import Control.Exception(assert)
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Generators
 import GHC.Integer.GMP.Internals(recipModInteger)
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 100
 
-generateModInvOps :: File
-generateModInvOps = File {
+generateModInvOps :: RustModule
+generateModInvOps = RustModule {
     predicate = \ me others -> (me + 64) `elem` others,
     outputName = "modinv",
     isUnsigned = True,
diff --git a/generation/src/ModOps.hs b/generation/src/ModOps.hs
index ca12033..df3f2e4 100644
--- a/generation/src/ModOps.hs
+++ b/generation/src/ModOps.hs
@@ -4,20 +4,20 @@ module ModOps(modulusOps)
 
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Generators
 import GHC.Integer.GMP.Internals(powModInteger)
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 1000
 
-modulusOps :: File
-modulusOps = File {
+modulusOps :: RustModule
+modulusOps = RustModule {
     predicate = \ me others -> (me * 2) `elem` others,
     outputName = "modops",
     isUnsigned = True,
diff --git a/generation/src/Multiply.hs b/generation/src/Multiply.hs
index e09e5a2..64d8867 100644
--- a/generation/src/Multiply.hs
+++ b/generation/src/Multiply.hs
@@ -9,7 +9,6 @@ import Data.Bits((.&.))
 import Data.List(union)
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen(toLit)
 import Generators
 import Karatsuba
@@ -17,13 +16,14 @@ import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-safeMultiplyOps :: File
-safeMultiplyOps = File {
+safeMultiplyOps :: RustModule
+safeMultiplyOps = RustModule {
     predicate = \ me others -> (me * 2) `elem` others,
     outputName = "safe_mul",
     isUnsigned = True,
@@ -31,8 +31,8 @@ safeMultiplyOps = File {
     testCase = Just generateSafeTests
 }
 
-unsafeMultiplyOps :: File
-unsafeMultiplyOps = File {
+unsafeMultiplyOps :: RustModule
+unsafeMultiplyOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "unsafe_mul",
     isUnsigned = True,
diff --git a/generation/src/RustModule.hs b/generation/src/RustModule.hs
new file mode 100644
index 0000000..be5fecb
--- /dev/null
+++ b/generation/src/RustModule.hs
@@ -0,0 +1,191 @@
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE RankNTypes  #-}
+module RustModule(
+         RustModule(..),
+         Task(..),
+         generateTasks,
+         testFile
+       )
+ where
+
+import Control.Monad(forM_)
+import Data.Char(toUpper)
+import Data.List(isPrefixOf, partition)
+import Data.Map.Strict(Map)
+import qualified Data.Map.Strict as Map
+import Data.Maybe(mapMaybe)
+import Language.Rust.Data.Ident(mkIdent)
+import Language.Rust.Data.Position(Span, spanOf)
+import Language.Rust.Pretty(writeSourceFile)
+import Language.Rust.Quote(item, sourceFile)
+import Language.Rust.Syntax(Item(..), SourceFile(..), Visibility(..))
+import System.IO(Handle,hPutStrLn)
+import System.Random(RandomGen(..))
+
+data RustModule = RustModule {
+    predicate :: Word -> [Word] -> Bool,
+    outputName :: String,
+    isUnsigned :: Bool,
+    generator :: Word -> [Word] -> SourceFile Span,
+    testCase :: forall g. RandomGen g => Maybe (Word -> g -> [Map String String])
+}
+
+data Task = Task {
+    outputFile :: FilePath,
+    writer     :: Handle -> IO ()
+}
+
+testFile :: Bool -> Word -> FilePath
+testFile True  size = "U" ++ show5 size ++ ".test"
+testFile False size = "I" ++ show5 size ++ ".test"
+
+show5 :: Word -> String
+show5 = go . show
+ where
+  go x | length x < 5 = go ('0' : x)
+       | otherwise    = x
+
+generateTasks :: RandomGen g => g -> [RustModule] -> [Word] -> [Task]
+generateTasks rng modules sizes = allTheFiles
+ where
+   allTheFiles = implementationsAndTests ++
+                 [lump "src/signed", lump "src/unsigned"]
+   implementationsAndTests = concatMap generateModules sizes
+   --
+   lump prefix =
+     let allFiles = map outputFile implementationsAndTests
+         files = filter (prefix `isPrefixOf`) allFiles
+         moduleFiles = map (drop (length prefix + 1)) files
+         moduleNames = map (takeWhile (/= '.')) moduleFiles 
+         moduleIdents = map mkIdent moduleNames
+         types = map (mkIdent . map toUpper) moduleNames
+         mods = map (\ name -> [item| mod $$name; |]) moduleIdents
+         uses = zipWith (\ mname tname -> [item| pub use $$mname::$$tname; |])
+                        moduleIdents types
+         file = [sourceFile| $@{mods} $@{uses} |]
+      in Task (prefix ++ ".rs") (\hndl -> writeSourceFile hndl file)
+   --
+   generateModules size =
+     let modules' = filter (\m -> predicate m size sizes) modules
+         (umodules, smodules) = partition isUnsigned modules'
+         unsignedTasks = generateImplementations "U" size umodules
+         signedTasks = generateImplementations "I" size smodules
+     in unsignedTasks ++ signedTasks ++ mapMaybe (generateTests size rng) modules'
+   -- 
+   generateImplementations startsWith size modules'
+     | null modules' = []
+     | otherwise =
+         let name = mkIdent (startsWith ++ show size)
+             baseInclude = [item| pub use self::base::$$name; |]
+             moduleSources = map (generateSubmodule size sizes) modules'
+             moduleFile | startsWith == "I" = "src/signed/i" ++ show size ++ ".rs"
+                        | otherwise         = "src/unsigned/u" ++ show size ++ ".rs"
+             allSource = SourceFile Nothing [] (baseInclude : moduleSources)
+         in [Task moduleFile (\ hndl -> writeSourceFile hndl allSource)]
+
+generateSubmodule :: Word -> [Word] -> RustModule -> Item Span
+generateSubmodule size allSizes m =
+  let SourceFile _ attrs internals = generator m size allSizes
+      modName = mkIdent (outputName m)
+      modSpan = spanOf internals
+  in Mod attrs CrateV modName (Just internals) modSpan
+
+generateTests :: RandomGen g =>
+                 Word -> g ->
+                 RustModule ->
+                 Maybe Task
+generateTests size rng m = fmap builder (testCase m)
+ where
+  builder testGeneration =
+    let outFile = "testdata/" ++ outputName m ++ "/" ++ testFile (isUnsigned m) size
+        testGenAction hndl = writeTestCase hndl (testGeneration size (snd (split rng)))
+    in Task outFile testGenAction
+
+--   basicTasks ++ moduleTasks
+-- where
+--  basicTasks = go rng files sizes
+--  moduleTasks = generateModules basicTasks
+--  --
+--  go :: RandomGen g => g -> [RustModule] -> [Word] -> [Task]
+--  go _ []             _  = []
+--  go g (_:rest)       [] = go g rest sizes
+--  go g files'@(file:_) (size:rest)
+--    | not (predicate file size sizes) = go g files' rest
+--    | otherwise =
+--        let (myg, theirg) = split g
+--            tasks = go theirg files' rest
+--            (signedBit, prefix) | isUnsigned file = ("unsigned", "u")
+--                                | otherwise       = ("signed", "i")
+--            mainTask = Task {
+--              outputFile = "src" </> signedBit </> (prefix ++ show size) </>
+--                           outputName file ++ ".rs",
+--              writer = \ hndl -> writeSourceFile hndl (generator file size sizes)
+--            }
+--        in case testCase file of
+--             Nothing ->
+--               mainTask : tasks
+--             Just caseGenerator ->
+--               let testTask = Task {
+--                     outputFile = "testdata" </> outputName file </> testFile (isUnsigned file) size,
+--                     writer = \ hndl -> writeTestCase hndl (caseGenerator size myg)
+--                   }
+--               in testTask : mainTask : tasks
+--
+--generateModules :: [Task] -> [Task]
+--generateModules tasks = Map.foldrWithKey maddModule [] fileMap ++ [signedTask, unsignedTask]
+-- where
+--  maddModule path mods acc
+--   | ("src/unsigned" `isPrefixOf` path) || ("src/signed" `isPrefixOf` path) =
+--        let (basePath, lowerName) = splitFileName (init path)
+--            upperName = map toUpper lowerName
+--            task = Task {
+--              outputFile = basePath </> lowerName ++ ".rs",
+--              writer = \ hndl ->
+--                do forM_ mods $ \ modl ->
+--                     hPutStrLn hndl ("mod " ++ modl ++ ";")
+--                   hPutStrLn hndl ("pub use base::" ++ upperName ++ ";")
+--            }
+--        in task : acc
+--   | otherwise =
+--        acc
+--  fileMap = foldr buildBaseMap Map.empty tasks
+--  buildBaseMap task acc =
+--    let (dir, fileext) = splitFileName (outputFile task)
+--        file = dropExtension fileext
+--    in Map.insertWith (++) dir [file] acc
+--  --
+--  signedTask = moduleTask "signed"
+--  unsignedTask = moduleTask "unsigned"
+--  moduleTask kind =
+--    let mods = Map.foldrWithKey (topModule kind) [] fileMap
+--        pubuses = Map.foldrWithKey (pubUse kind) [] fileMap
+--    in Task {
+--         outputFile = "src" </> (kind ++ ".rs"),
+--         writer = \ hndl ->
+--           writeSourceFile hndl [sourceFile|
+--             $@{mods}
+--             $@{pubuses}
+--          |]
+--       }
+--  topModule kind path _ acc
+--   | ("src/" ++ kind) `isPrefixOf` path =
+--        let lowerName = takeFileName (init path)
+--            modl = mkIdent lowerName
+--        in [item| mod $$modl; |] : acc
+--   | otherwise =
+--        acc
+--  pubUse kind path _ acc
+--   | ("src/" ++ kind) `isPrefixOf` path =
+--        let lowerName = takeFileName (init path)
+--            tname = mkIdent (map toUpper lowerName)
+--            modl = mkIdent lowerName
+--        in [item| pub use $$modl::$$tname; |] : acc
+--   | otherwise =
+--        acc
+--
+--
+writeTestCase :: Handle -> [Map String String] -> IO ()
+writeTestCase hndl tests =
+  forM_ tests $ \ test ->
+    forM_ (Map.toList test) $ \ (key, value) ->
+      hPutStrLn hndl (key ++ ": " ++ value)
diff --git a/generation/src/Scale.hs b/generation/src/Scale.hs
index 1f8aedf..9c6441b 100644
--- a/generation/src/Scale.hs
+++ b/generation/src/Scale.hs
@@ -8,20 +8,20 @@ module Scale(
 import Data.Bits((.&.))
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen(toLit)
 import Generators
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-safeScaleOps :: File
-safeScaleOps = File {
+safeScaleOps :: RustModule
+safeScaleOps = RustModule {
     predicate = \ me others -> (me + 64) `elem` others,
     outputName = "safe_scale",
     isUnsigned = True,
@@ -29,8 +29,8 @@ safeScaleOps = File {
     testCase = Just generateSafeTests
 }
 
-unsafeScaleOps :: File
-unsafeScaleOps = File {
+unsafeScaleOps :: RustModule
+unsafeScaleOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "unsafe_scale",
     isUnsigned = True,
diff --git a/generation/src/Shift.hs b/generation/src/Shift.hs
index 7edf958..d8d9f52 100644
--- a/generation/src/Shift.hs
+++ b/generation/src/Shift.hs
@@ -5,20 +5,20 @@ module Shift(shiftOps, signedShiftOps)
 import Data.Bits(shiftL,shiftR)
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen(toLit)
 import Generators
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-shiftOps :: File
-shiftOps = File {
+shiftOps :: RustModule
+shiftOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "shift",
     isUnsigned = True,
@@ -26,8 +26,8 @@ shiftOps = File {
     testCase = Just generateTests
 }
 
-signedShiftOps :: File
-signedShiftOps = File {
+signedShiftOps :: RustModule
+signedShiftOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "sshift",
     isUnsigned = False,
diff --git a/generation/src/Signed.hs b/generation/src/Signed.hs
index c3e7d55..d51ebe2 100644
--- a/generation/src/Signed.hs
+++ b/generation/src/Signed.hs
@@ -2,15 +2,14 @@
 module Signed(signedBaseOps)
  where
 
-import File
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 
-
-signedBaseOps :: File
-signedBaseOps = File {
+signedBaseOps :: RustModule
+signedBaseOps = RustModule {
     predicate = const (const True),
     outputName = "base",
     isUnsigned = False,
diff --git a/generation/src/Subtract.hs b/generation/src/Subtract.hs
index 55f2531..616ef29 100644
--- a/generation/src/Subtract.hs
+++ b/generation/src/Subtract.hs
@@ -10,20 +10,20 @@ module Subtract(
 import Data.Bits((.&.))
 import Data.Map.Strict(Map)
 import qualified Data.Map.Strict as Map
-import File
 import Gen(toLit)
 import Generators
 import Language.Rust.Data.Ident
 import Language.Rust.Data.Position
 import Language.Rust.Quote
 import Language.Rust.Syntax
+import RustModule
 import System.Random(RandomGen)
 
 numTestCases :: Int
 numTestCases = 3000
 
-safeSubtractOps :: File
-safeSubtractOps = File {
+safeSubtractOps :: RustModule
+safeSubtractOps = RustModule {
     predicate = \ me others -> (me + 64) `elem` others,
     outputName = "safe_sub",
     isUnsigned = True,
@@ -31,8 +31,8 @@ safeSubtractOps = File {
     testCase = Just generateSafeTests
 }
 
-safeSignedSubtractOps :: File
-safeSignedSubtractOps = File {
+safeSignedSubtractOps :: RustModule
+safeSignedSubtractOps = RustModule {
     predicate = \ me others -> (me + 64) `elem` others,
     outputName = "safe_ssub",
     isUnsigned = False,
@@ -40,8 +40,8 @@ safeSignedSubtractOps = File {
     testCase = Just generateSafeSignedTests
 }
 
-unsafeSubtractOps :: File
-unsafeSubtractOps = File {
+unsafeSubtractOps :: RustModule
+unsafeSubtractOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "unsafe_sub",
     isUnsigned = True,
@@ -49,8 +49,8 @@ unsafeSubtractOps = File {
     testCase = Just generateUnsafeTests
 }
 
-unsafeSignedSubtractOps :: File
-unsafeSignedSubtractOps = File {
+unsafeSignedSubtractOps :: RustModule
+unsafeSignedSubtractOps = RustModule {
     predicate = \ _ _ -> True,
     outputName = "unsafe_ssub",
     isUnsigned = False,