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

1 files changed, 11 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)