Add builtin arithmetic operators

* also allow choosing evaluator
* ensures equivalence of evaluators up-to α-renaming
* checks server accepts answers from challenge

1 files changed, 9 insertions, 6 deletions

diff --git a/lambda-calcul/haskell/src/Minilang/App.hs b/lambda-calcul/haskell/src/Minilang/App.hs
index 3373b75..0174547 100644
--- a/lambda-calcul/haskell/src/Minilang/App.hs
+++ b/lambda-calcul/haskell/src/Minilang/App.hs
@@ -20,9 +20,9 @@ import Data.Text.Encoding (decodeUtf8, encodeUtf8)
 import Data.Time (getCurrentTime)
 import Minilang.API (Challenge (..), LambdaAPI, Score (..), Token (..), User (..), newToken)
 import Minilang.Lambda.Parser (pretty)
-import Minilang.REPL (withInputs)
+import Minilang.REPL (withInputs, replEnvWith)
 import Minilang.REPL.Purer (PurerEnv (..))
-import Minilang.REPL.Types (Command (..), Content (..), In (..), Out (..), initialREPL)
+import Minilang.REPL.Types (Command (..), Content (..), Evaluator (..), In (..), Out (..), initialREPL)
 import Network.Wai.Application.Static (defaultFileServerSettings, staticApp)
 import Servant (ServerT, err400, err500, errBody, (:<|>) (..), err404)
 import Servant.Server (Application, Handler (..), Tagged (..))
@@ -31,15 +31,17 @@ import System.Random (StdGen)
 data Env = Env
   { gen :: TVar StdGen,
     users :: TVar (Map Token Score),
-    challenges :: [Challenge]
+    challenges :: [Challenge],
+    evaluator :: Evaluator
   }
 
-makeEnv :: StdGen -> [Challenge] -> IO Env
-makeEnv gen challenges =
+makeEnv :: StdGen -> [Challenge] -> Evaluator -> IO Env
+makeEnv gen challenges ev =
   Env
     <$> newTVarIO gen
     <*> newTVarIO mempty
     <*> pure challenges
+    <*> pure ev
 
 newtype AppM a = AppM {runAppM :: ReaderT Env IO a}
   deriving newtype (Functor, Applicative, Monad, MonadIO, MonadReader Env)
@@ -147,7 +149,8 @@ postAnswer Nothing _ = liftIO $ throwM $ err400 {errBody = "Missing token"}
 postAnswer (Just token) expected = do
   checkUserToken token
   Challenge {expr} <- getCurrentChallenge token
-  let PurerEnv {outputs} = withInputs initialREPL [Com (Load (Data expr))]
+  ev <- asks evaluator
+  let PurerEnv {outputs} = withInputs (replEnvWith ev) [Com (Load (Data expr))]
       result = evaluateOutputs outputs expected
   updateUserLastTest token result
   case result of