feat: main program evaluates s-expressions

1 files changed, 10 insertions, 5 deletions

diff --git a/lambda-calcul/haskell/src/Minilang/IO.hs b/lambda-calcul/haskell/src/Minilang/IO.hs
index c468316..28b6f01 100644
--- a/lambda-calcul/haskell/src/Minilang/IO.hs
+++ b/lambda-calcul/haskell/src/Minilang/IO.hs
@@ -9,16 +9,21 @@ import Data.Text.Encoding
 import Data.Text.Encoding.Error (lenientDecode)
 import Minilang.Lambda.Eval (eval)
 import System.IO (Handle)
+import Minilang.Lambda.Parser (parse, desugar)
 
 -- | Read a "program" from @hin@ handle, evaluate it and dump the result
 -- on @hout@.
 runEval :: Handle -> Handle -> IO ()
 runEval hin hout = do
-  programText <- Text.unpack . decodeUtf8With lenientDecode <$> BS.hGetContents hin
-  let ast = read programText
-      env = mempty
-      result = eval ast env
+  programText <- decodeUtf8With lenientDecode <$> BS.hGetContents hin
+  let parsed = parse programText
+      result = case parsed of
+         Left err -> show err
+         Right ast ->
+           let term = desugar ast
+               env = mempty
+           in show $ eval term env
 
   BS.hPut
     hout
-    (encodeUtf8 (Text.pack (show result) <> "\n"))
+    (encodeUtf8 (Text.pack result <> "\n"))