planar direction sum type

editors/emacs/swarm-mode.el

@@ -116,11 +116,11 @@
                "north"
                "west"
                "south"
+               "down"
+               "forward"
                "left"
-               "right"
                "back"
-               "forward"
-               "down"
+               "right"
              ))
              (x-types '("int" "text" "dir" "bool" "cmd" "void" "unit" "actor"))
 

editors/vscode/DEVELOPING.md

@@ -63,3 +63,16 @@ vsce package --baseImagesUrl "https://raw.githubusercontent.com/swarm-game/swarm
 ```
 
 To share this extension with the world, read on https://code.visualstudio.com/docs about publishing an extension or ask @xsebek to do it.
+
+## Troubleshooting
+
+If you encounter an error that looks like this:
+```
+ERROR in test case test/hello.sw
+    -- existing snapshot
+    ++ new changes
+```
+Then you may have to update the test snapshot as follows:
+```
+npm test vscode-tmgrammar-snap -- --updateSnapshot
+```

editors/vscode/syntaxes/swarm.tmLanguage.json

@@ -89,7 +89,7 @@
 			"patterns": [
 				{
 				"name": "variable.language.dir",
-				"match": "\\b(?i)(east|north|west|south|left|right|back|forward|down)\\b"
+				"match": "\\b(?i)(east|north|west|south|down|forward|left|back|right|)\\b"
 				},
 				{
 				"name": "variable.parameter",

editors/vscode/test/hello.sw.snap

@@ -18,8 +18,5 @@
 >
 >return "";
 #^^^^^^ source.swarm keyword.other
-#      ^ source.swarm
-#       ^ source.swarm string.quoted.double
-#        ^ source.swarm string.quoted.double
-#         ^^ source.swarm
+#      ^^^^^ source.swarm
 >

src/Swarm/Game/Location.hs

@@ -44,7 +44,7 @@ import Data.Map qualified as M
 import Data.Yaml (FromJSON (parseJSON), ToJSON (toJSON))
 import Linear (Additive (..), V2 (..), negated, norm, perp, unangle)
 import Linear.Affine (Affine (..), Point (..), origin)
-import Swarm.Language.Syntax (AbsoluteDir (..), Direction (..), RelativeDir (..), isCardinal)
+import Swarm.Language.Syntax (AbsoluteDir (..), Direction (..), PlanarRelativeDir (..), RelativeDir (..), isCardinal)
 import Swarm.Util qualified as Util
 
 -- $setup
@@ -122,11 +122,11 @@ down = zero
 applyTurn :: Direction -> Heading -> Heading
 applyTurn d = case d of
   DRelative e -> case e of
-    DLeft -> perp
-    DRight -> negated . perp
-    DBack -> negated
+    DPlanar DLeft -> perp
+    DPlanar DRight -> negated . perp
+    DPlanar DBack -> negated
+    DPlanar DForward -> id
     DDown -> const down
-    DForward -> id
   DAbsolute e -> const $ toHeading e
 
 -- | Mapping from heading to their corresponding cardinal directions.
@@ -143,9 +143,9 @@ toDirection v = M.lookup v cardinalDirs
 
 -- | Example:
 --      DWest `relativeTo` DSouth == DRight
-relativeTo :: AbsoluteDir -> AbsoluteDir -> RelativeDir
+relativeTo :: AbsoluteDir -> AbsoluteDir -> PlanarRelativeDir
 relativeTo targetDir referenceDir =
-  [DForward, DLeft, DBack, DRight] !! indexDiff
+  toEnum indexDiff
  where
   enumCount = length (Util.listEnums :: [AbsoluteDir])
   indexDiff = ((-) `on` fromEnum) targetDir referenceDir `mod` enumCount

src/Swarm/Game/Step.hs

@@ -1439,7 +1439,8 @@ execConst c vs s k = do
               if countByName "compass" inst >= 1
                 then Just $ DAbsolute entityDir
                 else case mh >>= toDirection of
-                  Just (DAbsolute robotDir) -> Just $ DRelative $ entityDir `relativeTo` robotDir
+                  Just (DAbsolute robotDir) ->
+                    Just . DRelative . DPlanar $ entityDir `relativeTo` robotDir
                   _ -> Nothing -- This may happen if the robot is facing "down"
             val = VDir $ fromMaybe (DRelative DDown) $ do
               entLoc <- firstFound
@@ -2122,8 +2123,8 @@ execConst c vs s k = do
    where
     directionText = case d of
       DRelative DDown -> "under"
-      DRelative DForward -> "ahead of"
-      DRelative DBack -> "behind"
+      DRelative (DPlanar DForward) -> "ahead of"
+      DRelative (DPlanar DBack) -> "behind"
       _ -> directionSyntax d <> " of"
 
   goAtomic :: HasRobotStepState sig m => m CESK

src/Swarm/Language/Syntax.hs

@@ -16,6 +16,7 @@ module Swarm.Language.Syntax (
   Direction (..),
   AbsoluteDir (..),
   RelativeDir (..),
+  PlanarRelativeDir (..),
   directionSyntax,
   isCardinal,
   allDirs,
@@ -153,20 +154,27 @@ instance FromJSONKey AbsoluteDir where
 -- | A relative direction is one which is defined with respect to the
 --   robot's frame of reference; no special capability is needed to
 --   use them.
-data RelativeDir = DLeft | DRight | DBack | DForward | DDown
+data RelativeDir = DPlanar PlanarRelativeDir | DDown
+  deriving (Eq, Ord, Show, Read, Generic, Data, Hashable, ToJSON, FromJSON)
+
+-- | Caution: Do not alter this ordering, as there exist functions that depend on it
+-- (e.g. "nearestDirection" and "relativeTo").
+data PlanarRelativeDir = DForward | DLeft | DBack | DRight
   deriving (Eq, Ord, Show, Read, Generic, Data, Hashable, ToJSON, FromJSON, Enum, Bounded)
 
 -- | The type of directions. Used /e.g./ to indicate which way a robot
 --   will turn.
 data Direction = DAbsolute AbsoluteDir | DRelative RelativeDir
   deriving (Eq, Ord, Show, Read, Generic, Data, Hashable, ToJSON, FromJSON)
 
--- | Direction name is generated from Direction data constuctor
+-- | Direction name is generated from Direction data constructor
 -- e.g. DLeft becomes "left"
 directionSyntax :: Direction -> Text
 directionSyntax d = toLower . T.tail . from $ case d of
   DAbsolute x -> show x
-  DRelative x -> show x
+  DRelative x -> case x of
+    DPlanar y -> show y
+    _ -> show x
 
 -- | Check if the direction is absolute (e.g. 'north' or 'south').
 isCardinal :: Direction -> Bool
@@ -175,7 +183,7 @@ isCardinal = \case
   _ -> False
 
 allDirs :: [Direction]
-allDirs = map DAbsolute Util.listEnums <> map DRelative Util.listEnums
+allDirs = map DAbsolute Util.listEnums <> map DRelative (DDown : map DPlanar Util.listEnums)
 
 ------------------------------------------------------------
 -- Constants