print haddock coverage info on stdout when generating docs

A module's haddockable items are its exports and the module itself.
The output is lightly formatted so you can align the :'s and sort
for readability.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/Haddock/Interface.hs b/src/Haddock/Interface.hs
index 0c171cbc..81919aed 100644
--- a/src/Haddock/Interface.hs
+++ b/src/Haddock/Interface.hs
@@ -46,6 +46,7 @@ import qualified Data.Map as Map
 import Distribution.Verbosity
 import System.Directory
 import System.FilePath
+import Text.Printf
 
 import Digraph
 import Exception
@@ -161,6 +162,13 @@ processModule verbosity modsum flags modMap instIfaceMap = do
       out verbosity verbose "Creating interface..."
       (interface, msg) <- runWriterGhc $ createInterface tm flags modMap instIfaceMap
       liftIO $ mapM_ putStrLn msg
+      let (haddockable, haddocked) = ifaceHaddockCoverage interface
+          percentage = round (fromIntegral haddocked * 100 / fromIntegral haddockable :: Double) :: Int
+          coveragemsg = printf "haddock coverage for %s: %7s %3d%%"
+                        (ifaceOrigFilename interface)
+                        (printf "%d/%d" haddocked haddockable ::  String)
+                        percentage
+      out verbosity normal coveragemsg
       interface' <- liftIO $ evaluate interface
       return (Just interface')
     else