Development.IDE.Spans.AtPoint: pointCommand: explain

Author: Anton-Latukha

ghcide/src/Development/IDE/Spans/AtPoint.hs

@@ -386,8 +386,11 @@ defRowToSymbolInfo (DefRow{..}:.(modInfoSrcFile -> Just srcFile))
     end   = Position (defELine - 1) (defECol - 1)
 defRowToSymbolInfo _ = Nothing
 
-pointCommand :: HieASTs t -> Position -> (HieAST t -> a) -> [a]
-pointCommand hf pos k =
+pointCommand :: HieASTs t -- ^ Get AST
+  -> Position -- ^ point at position
+  -> (HieAST t -> a) -- ^ extact data with a getter
+  -> [a] -- ^ all data recieved
+pointCommand hf pos getter =
     catMaybes $ M.elems $ flip M.mapWithKey (getAsts hf) $ \fs ast ->
       -- Since GHC 9.2:
       -- getAsts :: Map HiePath (HieAst a)
@@ -399,9 +402,8 @@ pointCommand hf pos k =
       --
       -- 'coerce' here to avoid an additional function for maintaining
       -- backwards compatibility.
-      case selectSmallestContaining (sp $ coerce fs) ast of
-        Nothing   -> Nothing
-        Just ast' -> Just $ k ast'
+      let smallestRange = selectSmallestContaining (sp $ coerce fs) ast in
+      fmap getter smallestRange
  where
    sloc fs = mkRealSrcLoc fs (line+1) (cha+1)
    sp fs = mkRealSrcSpan (sloc fs) (sloc fs)