From 9a67492dcc44f4a3f234292df310c30ffb63b80e Mon Sep 17 00:00:00 2001
From: kokobd <contact@zelinf.net>
Date: Wed, 21 Sep 2022 23:20:24 +0800
Subject: [PATCH] wip: add comments

---
 .../src/Ide/Plugin/HaddockComments.hs         |  1 -
 .../src/Ide/Plugin/HaddockComments/Data.hs    | 23 +++++++++++++------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments.hs b/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments.hs
index 724e82efbfa..66ea479416e 100644
--- a/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments.hs
+++ b/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments.hs
@@ -50,7 +50,6 @@ codeActionProvider ideState _pId (CodeActionParams _ _ (TextDocumentIdentifier u
 genList :: [Maybe [LHsDecl GhcPs] -> Maybe Anns -> Range -> Maybe (T.Text, TextEdit)]
 genList =
   [ runGenCommentsSimple genForSig,
-    -- runGenCommentsSimple genForRecord
     runGenComments genForDataDecl
   ]
 
diff --git a/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments/Data.hs b/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments/Data.hs
index ddc3c210303..5797f5614ca 100644
--- a/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments/Data.hs
+++ b/plugins/hls-haddock-comments-plugin/src/Ide/Plugin/HaddockComments/Data.hs
@@ -35,24 +35,33 @@ updateDataAnns decl@(L declLoc (TyClD _ DataDecl {tcdDataDefn = HsDataDefn { dd_
     getAnnsT >>= (\anns -> unless (missingSomeHaddock anns cons) (lift Nothing))
 
     -- visit each constructor and field
-    addHaddockCommentsToList True declLoc cons
+    addHaddockCommentsToList True declLoc (G AnnVbar) cons
     for_ cons $ \case
-        L conLoc ConDeclH98 { con_args = RecCon (L _ fields) } -> addHaddockCommentsToList False conLoc fields
+        L conLoc ConDeclH98 { con_args = RecCon (L _ fields) } -> addHaddockCommentsToList False conLoc (G AnnComma) fields
         _ -> pure ()
     modifyAnnsT $ Map.adjust (\ann -> ann {annPriorComments = []}) (mkAnnKey decl)
-updateDataAnns _ = pure ()
+updateDataAnns _ = lift Nothing
 
--- TODO Add explaination to this complex function.
-addHaddockCommentsToList :: (Data a, Monad m) => Bool -> SrcSpan -> [Located a] -> TransformT m ()
-addHaddockCommentsToList usePrevNodeAsAnchor outerLoc nodes =
+-- | Add haddock comments to a list of nodes
+addHaddockCommentsToList
+    :: (Data a, Monad m)
+    => Bool -- ^ If true, for each node, use previous node in the list as the anchor. Otherwise, use the outer node
+    -> SrcSpan -- ^ The outer node
+    -> KeywordId -- ^ The seperator between adjacent nodes
+    -> [Located a] -- ^ The list of nodes. Haddock comments will be added to each of them
+    -> TransformT m ()
+addHaddockCommentsToList usePrevNodeAsAnchor outerLoc seperator nodes =
     for_ (zip nodes (Nothing: fmap Just nodes)) $ \(node, prevNode) -> do
+        -- We don't add new ones to nodes with existing haddock comments.
         addHaddockCommentToCurrentNode <- fmap (not . fromMaybe True . flip hasHaddock node) getAnnsT
         when addHaddockCommentToCurrentNode $ do
+            -- Check if the start of 'node' is on the end line of 'prevNode'.
+            -- When this occurs, we do not preserve the indentation. Instead, we move the seperator to the next line
             let sameLineAsPrev = maybe False (\prevNode' -> notSeperatedByLineEnding prevNode' node) prevNode
             when sameLineAsPrev $ modifyAnnsT $ \anns ->
                 let updateSepAnn :: Annotation -> Annotation
                     updateSepAnn ann = ann {annsDP =
-                        Map.toList . Map.adjust (const (DP (1,0))) (G AnnVbar) . Map.fromList $ annsDP ann}
+                        Map.toList . Map.adjust (const (DP (1,0))) seperator . Map.fromList $ annsDP ann}
                  in flip (maybe anns) prevNode $ \prevNode' -> Map.adjust updateSepAnn (mkAnnKey prevNode') anns
             let anchorCol = maybe 0 srcSpanStartCol . realSpan . maybe outerLoc getLoc $
                     if usePrevNodeAsAnchor then prevNode else Nothing