1 files changed, 13 insertions, 7 deletions
diff --git a/app/Code.hs b/app/Code.hs
index 00d1d1c..5721d17 100644
--- a/app/Code.hs
+++ b/app/Code.hs
@@ -1,8 +1,10 @@
 module Code where
 
+import Control.Monad.Trans.State.Lazy
 import qualified Data.Map as M
 import IR (Id(..), StrTable)
 import Operators (Ops)
+import System.Console.Haskeline
 
 data Datum
   = Atom Int -- unifies a constant
@@ -12,16 +14,10 @@ data Datum
   | HeapRef Int (Maybe Int) -- heap structure idx
   deriving (Show, Eq, Ord)
 
-data BuiltinFunc =
-  BuiltinFunc (Interp -> Interp)
-
-instance Show BuiltinFunc where
-  show _ = "BuiltinFunc _"
-
 data Instr
   = U Datum -- something unifiable
   | NoGoal -- trivial goal (directly after head)
-  | Builtin BuiltinFunc -- trivial goal (directly after head)
+  | Invoke Builtin -- also directly after head
   | Goal -- a new goal (set head)
   | Call -- all seems okay, call the head's hoal
   | LastCall -- tail call the head's goal
@@ -64,3 +60,13 @@ data Interp =
     , strtable :: StrTable -- string table
     }
   deriving (Show)
+
+type PrlgEnv a = StateT Interp (InputT IO) a
+
+type BuiltinFn = PrlgEnv (Maybe (Either String Bool))
+
+data Builtin =
+  Builtin BuiltinFn
+
+instance Show Builtin where
+  show _ = "Builtin _"