Move the Generator program into a proper benchmark

SJW.cabal

@@ -49,12 +49,14 @@ executable sjw
   default-language:    Haskell2010
   ghc-options:         -Wall
 
-executable generator
-  main-is:             tests/Generator.hs
-  build-depends:       base >=4.11 && <4.13
+benchmark big-src
+  type:                exitcode-stdio-1.0
+  main-is:             benchmark/Main.hs
+  build-depends:       base >= 4.9 && <4.15
                      , directory
                      , filepath
                      , random
                      , SJW
+                     , time
   default-language:    Haskell2010
   ghc-options:         -Wall

benchmark/Main.hs

@@ -1,9 +1,10 @@
 {-# LANGUAGE NamedFieldPuns #-}
 module Main where
 
-import SJW (Path(..))
+import SJW (Path(..), compile, source, sourceCode)
 import Control.Monad (foldM)
-import System.Directory (createDirectoryIfMissing)
+import Data.Time.Clock (diffUTCTime, getCurrentTime)
+import System.Directory (createDirectoryIfMissing, doesDirectoryExist)
 import System.FilePath ((</>), (<.>))
 import System.Random (randomRIO)
 import Text.Printf (printf)
@@ -26,7 +27,7 @@ addDependency path fakeModule = fakeModule {
   }
 
 destDir :: FilePath
-destDir = "tests/giant"
+destDir = "/tmp/SJW-benchmark/giant"
 
 generateCode :: FakeModule -> String
 generateCode (FakeModule {dependencies}) = unlines $
@@ -80,4 +81,17 @@ writeFakeModule fakeModule@(FakeModule {name = Path components}) =
   writeFile (directory </> head fileName <.> "js") $ generateCode fakeModule
 
 main :: IO ()
-main = generateDAG 10000 10 (50, 100) >>= mapM_ writeFakeModule
+main = do
+  directoryExists <- doesDirectoryExist destDir
+  if not directoryExists
+  then do
+    createDirectoryIfMissing True destDir
+    generateDAG 10000 10 (50, 100) >>= mapM_ writeFakeModule
+  else return ()
+  start <- getCurrentTime
+  maybe (return ()) (\_ -> return ()) =<< sourceCode =<< compile (source [destDir])
+  end <- getCurrentTime
+  mapM_ putStrLn [
+        "Compiled 10k modules in " ++ show (diffUTCTime end start)
+      , "Left the fake project in " ++ destDir ++ " if you want to poke around"
+    ]