Per-module extension flags and language listing.

Any extensions that are not enabled by a used language (Haskell2010
&c) will be shown. Furthermore, any implicitly enabled are also going
to be shown. While we could eliminate this either by using the GHC API
or a dirty hack, I opted not to: if a user doesn't want the implied
flags to show, they are recommended to use enable extensions more
carefully or individually. Perhaps this will encourage users to not
enable the most powerful flags needlessly. Enabled with show-extensions.

Conflicts:
	src/Haddock/InterfaceFile.hs

3 files changed, 29 insertions, 15 deletions

diff --git a/src/Haddock/Interface/Create.hs b/src/Haddock/Interface/Create.hs
index 825e9624..6c20f00b 100644
--- a/src/Haddock/Interface/Create.hs
+++ b/src/Haddock/Interface/Create.hs
@@ -3,8 +3,9 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Haddock.Interface.Create
--- Copyright   :  (c) Simon Marlow 2003-2006,
---                    David Waern  2006-2009
+-- Copyright   :  (c) Simon Marlow      2003-2006,
+--                    David Waern       2006-2009,
+--                    Mateusz Kowalczyk 2013
 -- License     :  BSD-like
 --
 -- Maintainer  :  haddock@projects.haskell.org
@@ -218,16 +219,20 @@ mkDocOpts mbOpts flags mdl = do
       [] -> tell ["No option supplied to DOC_OPTION/doc_option"] >> return []
       xs -> liftM catMaybes (mapM parseOption xs)
     Nothing -> return []
-  if Flag_HideModule (moduleString mdl) `elem` flags
-    then return $ OptHide : opts
-    else return opts
+  hm <- if Flag_HideModule (moduleString mdl) `elem` flags
+        then return $ OptHide : opts
+        else return opts
+  if Flag_ShowExtensions (moduleString mdl) `elem` flags
+    then return $ OptShowExtensions : hm
+    else return hm
 
 
 parseOption :: String -> ErrMsgM (Maybe DocOption)
-parseOption "hide"           = return (Just OptHide)
-parseOption "prune"          = return (Just OptPrune)
-parseOption "ignore-exports" = return (Just OptIgnoreExports)
-parseOption "not-home"       = return (Just OptNotHome)
+parseOption "hide"            = return (Just OptHide)
+parseOption "prune"           = return (Just OptPrune)
+parseOption "ignore-exports"  = return (Just OptIgnoreExports)
+parseOption "not-home"        = return (Just OptNotHome)
+parseOption "show-extensions" = return (Just OptShowExtensions)
 parseOption other = tell ["Unrecognised option: " ++ other] >> return Nothing
 
 
@@ -649,7 +654,7 @@ lookupDocs n warnings docMap argMap subMap =
 -- 2) B is visible, but not all its exports are in scope in A, in which case we
 --    only return those that are.
 -- 3) B is visible and all its exports are in scope, in which case we return
---    a single 'ExportModule' item. 
+--    a single 'ExportModule' item.
 moduleExports :: Module           -- ^ Module A
               -> ModuleName       -- ^ The real name of B, the exported module
               -> DynFlags         -- ^ The flags used when typechecking A
diff --git a/src/Haddock/Interface/LexParseRn.hs b/src/Haddock/Interface/LexParseRn.hs
index 73f2c165..c302e4f0 100644
--- a/src/Haddock/Interface/LexParseRn.hs
+++ b/src/Haddock/Interface/LexParseRn.hs
@@ -4,6 +4,7 @@
 -- |
 -- Module      :  Haddock.Interface.LexParseRn
 -- Copyright   :  (c) Isaac Dupree 2009,
+--                    Mateusz Kowalczyk 2013
 -- License     :  BSD-like
 --
 -- Maintainer  :  haddock@projects.haskell.org
@@ -17,7 +18,7 @@ module Haddock.Interface.LexParseRn
   , processModuleHeader
   ) where
 
-
+import qualified Data.IntSet as IS
 import Haddock.Types
 import Haddock.Parser
 import Haddock.Interface.ParseModuleHeader
@@ -28,11 +29,11 @@ import Data.List
 import Data.Maybe
 import FastString
 import GHC
+import DynFlags (ExtensionFlag(..), languageExtensions)
 import Name
 import Outputable
 import RdrName
 
-
 processDocStrings :: DynFlags -> GlobalRdrEnv -> [HsDocString] -> ErrMsgM (Maybe (Doc Name))
 processDocStrings dflags gre strs = do
   docs <- catMaybes <$> mapM (processDocStringParas dflags gre) strs
@@ -82,7 +83,14 @@ processModuleHeader dflags gre safety mayStr = do
                 hmi' = hmi { hmi_description = descr }
                 doc' = rename dflags gre doc
             return (hmi', Just doc')
-  return (hmi { hmi_safety = Just $ showPpr dflags safety }, doc)
+
+  let flags :: [ExtensionFlag]
+      -- We remove the flags implied by the language setting and we display the language instead
+      flags = map toEnum (IS.toList $ extensionFlags dflags) \\ languageExtensions (language dflags)
+  return (hmi { hmi_safety = Just $ showPpr dflags safety
+              , hmi_language = language dflags
+              , hmi_extensions = flags
+              } , doc)
   where
     failure = (emptyHaddockModInfo, Nothing)
 
diff --git a/src/Haddock/Interface/ParseModuleHeader.hs b/src/Haddock/Interface/ParseModuleHeader.hs
index ade28728..0be2511f 100644
--- a/src/Haddock/Interface/ParseModuleHeader.hs
+++ b/src/Haddock/Interface/ParseModuleHeader.hs
@@ -61,7 +61,9 @@ parseModuleHeader dflags str0 =
             hmi_maintainer = maintainerOpt,
             hmi_stability = stabilityOpt,
             hmi_portability = portabilityOpt,
-            hmi_safety = Nothing
+            hmi_safety = Nothing,
+            hmi_language = Nothing, -- set in LexParseRn
+            hmi_extensions = [] -- also set in LexParseRn
             }, doc)
 
 -- | This function is how we read keys.
@@ -158,4 +160,3 @@ parseKey key toParse0 =
       extractPrefix (c1:cs1) (c2:cs2)
          | toUpper c1 == toUpper c2 = extractPrefix cs1 cs2
          | otherwise = Nothing
-