Replace TSyntax with Syntax in a couple places, plus a bit of refactoring (#2074)

A bit of initial refactoring towards #495 .

- Replace `TSyntax` with `Syntax` in a couple places where the types are not needed.
    - Once we implement #495 producing `TSyntax` is going to get a lot harder, so the more places we can eliminate it the better.
- Also some related minor refactoring, and a new function `readNonemptyTerm`.  We're not using it yet, but (1) I thought I would need it in this PR, and (2) when I realized I didn't, I decided to leave it there anyway since it will likely come in handy later.

src/swarm-engine/Swarm/Game/Scenario/Scoring/CodeSize.hs

@@ -12,7 +12,7 @@ import GHC.Generics (Generic)
 import Swarm.Language.Syntax
 
 data CodeSizeDeterminators = CodeSizeDeterminators
-  { initialCode :: Maybe TSyntax
+  { initialCode :: Maybe Syntax
   , hasUsedREPL :: Bool
   }
   deriving (Show)

src/swarm-engine/Swarm/Game/State.hs

@@ -35,6 +35,8 @@ module Swarm.Game.State (
   -- ** GameState initialization
   initGameState,
   CodeToRun (..),
+  toRunSource,
+  toRunSyntax,
   Sha1 (..),
   SolutionSource (..),
   parseCodeFile,
@@ -127,7 +129,12 @@ data SolutionSource
     -- on a leaderboard.
     PlayerAuthored FilePath Sha1
 
-data CodeToRun = CodeToRun SolutionSource TSyntax
+data CodeToRun = CodeToRun
+  { _toRunSource :: SolutionSource
+  , _toRunSyntax :: TSyntax
+  }
+
+makeLenses ''CodeToRun
 
 getRunCodePath :: CodeToRun -> Maybe FilePath
 getRunCodePath (CodeToRun solutionSource _) = case solutionSource of

src/swarm-engine/Swarm/Game/State/Initialize.hs

@@ -50,7 +50,7 @@ import Swarm.Game.State.Substate
 import Swarm.Game.Universe as U (offsetBy)
 import Swarm.Game.World.Gen (Seed)
 import Swarm.Language.Capability (constCaps)
-import Swarm.Language.Syntax (allConst)
+import Swarm.Language.Syntax (allConst, erase)
 import Swarm.Language.Types
 import Swarm.Util (binTuples, (?))
 import System.Clock qualified as Clock
@@ -99,7 +99,7 @@ pureScenarioToGameState scenario theSeed now toRun gsc =
       & randomness . randGen .~ mkStdGen theSeed
       & recipesInfo %~ modifyRecipesInfo
       & landscape .~ mkLandscape sLandscape worldTuples theSeed
-      & gameControls . initiallyRunCode .~ initialCodeToRun
+      & gameControls . initiallyRunCode .~ (erase <$> initialCodeToRun)
       & gameControls . replStatus .~ case running of -- When the base starts out running a program, the REPL status must be set to working,
       -- otherwise the store of definition cells is not saved (see #333, #838)
         False -> REPLDone Nothing
@@ -118,11 +118,9 @@ pureScenarioToGameState scenario theSeed now toRun gsc =
   baseID = 0
   (things, devices) = partition (M.null . getMap . view entityCapabilities) (M.elems (entitiesByName em))
 
-  getCodeToRun (CodeToRun _ s) = s
-
   robotsByBasePrecedence = genRobotTemplates sLandscape worldTuples
 
-  initialCodeToRun = getCodeToRun <$> toRun
+  initialCodeToRun = view toRunSyntax <$> toRun
 
   robotListRaw =
     zipWith (instantiateRobot Nothing) [baseID ..] robotsByBasePrecedence

src/swarm-engine/Swarm/Game/State/Substate.hs

@@ -109,7 +109,7 @@ import Swarm.Game.Scenario.Topography.Structure.Recognition.Type (RecognizerAuto
 import Swarm.Game.State.Config
 import Swarm.Game.Tick (TickNumber (..))
 import Swarm.Game.World.Gen (Seed)
-import Swarm.Language.Syntax (Const, TSyntax)
+import Swarm.Language.Syntax (Const, Syntax)
 import Swarm.Language.Types (Polytype)
 import Swarm.Language.Value (Value)
 import Swarm.Log
@@ -302,7 +302,7 @@ data GameControls = GameControls
   { _replStatus :: REPLStatus
   , _replNextValueIndex :: Integer
   , _inputHandler :: Maybe (Text, Value)
-  , _initiallyRunCode :: Maybe TSyntax
+  , _initiallyRunCode :: Maybe Syntax
   }
 
 makeLensesNoSigs ''GameControls
@@ -318,7 +318,7 @@ inputHandler :: Lens' GameControls (Maybe (Text, Value))
 
 -- | Code that is run upon scenario start, before any
 -- REPL interaction.
-initiallyRunCode :: Lens' GameControls (Maybe TSyntax)
+initiallyRunCode :: Lens' GameControls (Maybe Syntax)
 
 data Discovery = Discovery
   { _allDiscoveredEntities :: Inventory

src/swarm-lang/Swarm/Language/Parser.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeFamilies #-}
 
 -- |
@@ -10,10 +11,13 @@
 -- typechecks, elaborates, and capability checks a term all at once.
 module Swarm.Language.Parser (
   readTerm,
+  readNonemptyTerm,
   readTerm',
 ) where
 
+import Control.Monad ((>=>))
 import Data.Bifunctor (first, second)
+import Data.Either.Extra (maybeToEither)
 import Data.Sequence (Seq)
 import Data.Text (Text)
 import Swarm.Language.Parser.Comment (populateComments)
@@ -25,6 +29,13 @@ import Swarm.Language.Syntax (Comment, Syntax)
 import Text.Megaparsec.Error (errorBundlePretty)
 import Witch (from)
 
+-- | Parse some input 'Text' completely as a 'Term', consuming leading
+--   whitespace and ensuring the parsing extends all the way to the
+--   end of the input 'Text'.  Returns an error if the term was only
+--   whitespace.
+readNonemptyTerm :: Text -> Either Text Syntax
+readNonemptyTerm = readTerm >=> maybeToEither "Empty term"
+
 -- | Parse some input 'Text' completely as a 'Term', consuming leading
 --   whitespace and ensuring the parsing extends all the way to the
 --   end of the input 'Text'.  Returns either the resulting 'Term' (or

src/swarm-tui/Swarm/TUI/Model/StateUpdate.hs

@@ -226,8 +226,8 @@ scenarioToAppState siPair@(scene, _) lp = do
   gameState .= gs
   void $ withLensIO uiState $ scenarioToUIState isAutoplaying siPair gs
  where
-  isAutoplaying = case runIdentity (initialCode lp) of
-    Just (CodeToRun ScenarioSuggested _) -> True
+  isAutoplaying = case fmap (view toRunSource) . runIdentity $ initialCode lp of
+    Just ScenarioSuggested -> True
     _ -> False
 
   withLensIO :: (MonadIO m, MonadState AppState m) => Lens' AppState x -> (x -> IO x) -> m x

weeder.toml

@@ -31,6 +31,7 @@ roots = [
     "^Swarm.Game.World.lookupTerrainM$",
     "^Swarm.Language.Context.withBindings$",
     "^Swarm.Language.Context.singleton$",
+    "^Swarm.Language.Parser.readNonemptyTerm$",
     "^Swarm.Language.Parser.Util.showShortError$",
     "^Swarm.Language.Pipeline.extractTCtx$",
     "^Swarm.Language.Pretty.Prec$",
@@ -43,7 +44,7 @@ roots = [
     "^Swarm.Util.reflow$",
     "^Swarm.Util.isSuccessOr$",
     "^Swarm.Util._NonEmpty$",
-    
+
     # True positives (unused lenses):
     # -------------------------------
     "^Swarm.Language.Typed.polytype$",