Add 'show' option to complement 'hide' (#752)

* Add 'show' option to complement 'hide'

The behaviour is for flags passed in the command line to override
flags in file headers. In the command line, later flags override
earlier ones.

Fixes #751 and #266.

* Add a '--show-all' option

2 files changed, 17 insertions, 10 deletions

diff --git a/haddock-api/src/Haddock/Interface/Create.hs b/haddock-api/src/Haddock/Interface/Create.hs
index 75e7e9a1..f218853b 100644
--- a/haddock-api/src/Haddock/Interface/Create.hs
+++ b/haddock-api/src/Haddock/Interface/Create.hs
@@ -312,16 +312,17 @@ mkDocOpts mbOpts flags mdl = do
       [] -> tell ["No option supplied to DOC_OPTION/doc_option"] >> return []
       xs -> liftM catMaybes (mapM parseOption xs)
     Nothing -> return []
-  hm <- if Flag_HideModule (moduleString mdl) `elem` flags
-        then return $ OptHide : opts
-        else return opts
-  ie <- if Flag_IgnoreAllExports `elem` flags
-        then return $ OptIgnoreExports : hm
-        else return hm
-  se <- if Flag_ShowExtensions (moduleString mdl) `elem` flags
-        then return $ OptShowExtensions : ie
-        else return ie
-  return se
+  pure (foldl go opts flags)
+  where
+    mdlStr = moduleString mdl
+
+    -- Later flags override earlier ones
+    go os m | m == Flag_HideModule mdlStr     = OptHide : os
+            | m == Flag_ShowModule mdlStr     = filter (/= OptHide) os
+            | m == Flag_ShowAllModules        = filter (/= OptHide) os
+            | m == Flag_IgnoreAllExports      = OptIgnoreExports : os
+            | m == Flag_ShowExtensions mdlStr = OptIgnoreExports : os
+            | otherwise                       = os
 
 parseOption :: String -> ErrMsgM (Maybe DocOption)
 parseOption "hide"            = return (Just OptHide)
diff --git a/haddock-api/src/Haddock/Options.hs b/haddock-api/src/Haddock/Options.hs
index caf1fefe..0609aa63 100644
--- a/haddock-api/src/Haddock/Options.hs
+++ b/haddock-api/src/Haddock/Options.hs
@@ -86,6 +86,8 @@ data Flag
   | Flag_GenIndex
   | Flag_IgnoreAllExports
   | Flag_HideModule String
+  | Flag_ShowModule String
+  | Flag_ShowAllModules
   | Flag_ShowExtensions String
   | Flag_OptGhc String
   | Flag_GhcLibDir String
@@ -182,6 +184,10 @@ options backwardsCompat =
       "behave as if all modules have the\nignore-exports atribute",
     Option [] ["hide"] (ReqArg Flag_HideModule "MODULE")
       "behave as if MODULE has the hide attribute",
+    Option [] ["show"] (ReqArg Flag_ShowModule "MODULE")
+      "behave as if MODULE does not have the hide attribute",
+    Option [] ["show-all"] (NoArg Flag_ShowAllModules)
+      "behave as if not modules have the hide attribute",
     Option [] ["show-extensions"] (ReqArg Flag_ShowExtensions "MODULE")
       "behave as if MODULE has the show-extensions attribute",
     Option [] ["optghc"] (ReqArg Flag_OptGhc "OPTION")