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, 5 insertions, 4 deletions

diff --git a/lambda-calcul/haskell/src/Minilang/Server.hs b/lambda-calcul/haskell/src/Minilang/Server.hs
index 4252669..1b9fa25 100644
--- a/lambda-calcul/haskell/src/Minilang/Server.hs
+++ b/lambda-calcul/haskell/src/Minilang/Server.hs
@@ -26,6 +26,7 @@ import Data.Swagger (Swagger)
 import Data.Text (Text)
 import Minilang.API (Challenge, LambdaAPI, defaultChallenges)
 import Minilang.App (Env (..), lambdaApp, makeEnv, runApp)
+import Minilang.REPL.Types (Evaluator (..))
 import Minilang.Log
 import Minilang.OpenApi (lambdaSwagger)
 import Minilang.REPL.Net
@@ -45,16 +46,16 @@ data Server = Server
     serverPort :: Int
   }
 
--- | Starts HTTP server on given port.
+-- | Starts HTTP server on given port using the specified 'Evaluator'.
 --  This server serves static files from public/ directory and also
 --  exposes a WebSocket-based REPL under `/repl` path.
-startServer :: Int -> IO Server
-startServer serverPort = do
+startServer :: Int -> Evaluator -> IO Server
+startServer serverPort ev = do
   envs <- newTVarIO mempty
   logger <- newLog "minilang"
   loggerMiddleware <- runHTTPLog logger
   challenges <- readChallenges logger
-  env <- newStdGen >>= (`makeEnv` challenges)
+  env <- newStdGen >>= \g -> makeEnv g challenges ev
   let app =
         loggerMiddleware $
           runNetREPL logger envs (serveAPI env)