return southwest instead of northwest corner as structure location

src/Swarm/Game/Step.hs

@@ -1410,9 +1410,14 @@ execConst c vs s k = do
       [VText name, VInt idx] -> do
         registry <- use $ discovery . structureRecognition . foundStructures
         let maybeFoundStructures = M.lookup (StructureName name) $ foundByName registry
-            mkOutput mapNE = (NE.length xs, indexWrapNonEmpty xs idx ^. planar)
+            mkOutput mapNE = (NE.length xs, bottomLeftCorner)
              where
-              xs = NEM.keys mapNE
+              xs = NEM.toList mapNE
+              (pos, struc) = indexWrapNonEmpty xs idx
+              topLeftCorner = pos ^. planar
+              offsetHeight = V2 0 $ -fromIntegral (length (entityGrid struc) - 1)
+              bottomLeftCorner :: Location
+              bottomLeftCorner = topLeftCorner .+^ offsetHeight
         return $ mkReturn $ mkOutput <$> maybeFoundStructures
       _ -> badConst
     Floorplan -> case vs of

src/Swarm/Language/Syntax.hs

@@ -224,7 +224,7 @@ data Const
     Whereami
   | -- | Get the x, y coordinates of a named waypoint, by index
     Waypoint
-  | -- | Get the x, y coordinates of a constructed structure, by index
+  | -- | Get the x, y coordinates of southwest corner of a constructed structure, by index
     Structure
   | -- | Get the width and height of a structure template
     Floorplan
@@ -648,7 +648,7 @@ constInfo c = case c of
       , "A robot can use the count to know whether they have iterated over the full waypoint circuit."
       ]
   Structure ->
-    command 2 Intangible . doc "Get the x, y coordinates of a constructed structure, by name and index" $
+    command 2 Intangible . doc "Get the x, y coordinates of the southwest corner of a constructed structure, by name and index" $
       [ "The outermost type of the return value indicates whether any structure of such name exists."
       , "Since structures can have multiple occurrences, returns a tuple of (count, (x, y))."
       , "The supplied index will be wrapped automatically, modulo the structure count."