Add indentation to the paragraphs inserted in patterns

Ugly, but fixes #6. Ugly still better than non-valid-haskell result.

src-literatetests/tests.blt

@@ -702,6 +702,15 @@ showPackageDetailedInfo pkginfo =
 isValidPosition position | validX && validY = Just position
                          | otherwise        = Nothing
 
+#test issue-6-pattern-linebreak-validity
+## this is ugly, but at least syntactically valid.
+foo = Reflex.runSpiderHost $ ReflexHost.hostApp $ do
+  (inputEvent :: Reflex.Event Reflex.Spider String, inputFire :: String
+    -> IO Bool                                                         ) <-
+    ReflexHost.newExternalEvent
+  liftIO . forkIO . forever $ getLine >>= inputFire
+  ReflexHost.performEvent_ $ fmap (liftIO . putStrLn) inputEvent
+
 
 ###############################################################################
 ###############################################################################
@@ -738,11 +747,3 @@ isValidPosition position | validX && validY = Just position
 ##  where
 ##   role = stringProperty "WM_WINDOW_ROLE"
 
-#test linebreak
-#pending
-
-foo = Reflex.runSpiderHost $ ReflexHost.hostApp $ do
-  (inputEvent :: Reflex.Event Reflex.Spider String, inputFire :: String -> IO Bool)
-    <- ReflexHost.newExternalEvent
-  liftIO . forkIO . forever $ getLine >>= inputFire
-  ReflexHost.performEvent_ $ fmap (liftIO . putStrLn) inputEvent

src/Language/Haskell/Brittany/Layouters/Pattern.hs

@@ -109,10 +109,17 @@ layoutPat lpat@(L _ pat) = docWrapNode lpat $ case pat of
     case Seq.viewr patDocs of
       Seq.EmptyR -> error "cannot happen ljoiuxoasdcoviuasd"
       xR Seq.:> xN -> do
-        xN' <- docSeq
+        xN' <- -- at the moment, we don't support splitting patterns into
+               -- multiple lines. but we cannot enforce pasting everything
+               -- into one line either, because the type signature will ignore
+               -- this if we overflow sufficiently.
+               -- In order to prevent syntactically invalid results in such
+               -- cases, we need the AddBaseY here.
+               -- This can all change when patterns get multiline support.
+               docAddBaseY BrIndentRegular $ docSeq
           [ appSep $ return xN
           , appSep $ docLit $ Text.pack "::"
-          , tyDoc
+          , docForceSingleline $ tyDoc
           ]
         return $ xR Seq.|> xN'
   ListPat elems _ _ ->