1 files changed, 28 insertions, 0 deletions
diff --git a/Eval.hs b/Eval.hs
new file mode 100644
index 0000000..af2cd3c
--- /dev/null
+++ b/Eval.hs
@@ -0,0 +1,28 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE RankNTypes #-}
+module Eval where
+
+import AST
+import ASTfunc
+
+
+eval :: Expr '[] t -> t
+eval = eval'Expr VZ
+
+eval'Expr :: Val env -> Expr env t -> t
+eval'Expr v (Expr e) = eval' eval'Expr v e
+
+eval' :: (forall env' t'. Val env' -> expr env' t' -> t')
+      -> Val env -> PExpr expr env t -> t
+eval' _ _ (Const _ x) = x
+eval' f v (Pair x y) = (f v x, f v y)
+eval' _ _ Nil = ()
+eval' f v (Prim op x) = applyOper op (f v x)
+eval' _ v (Var (V _ i)) = prjV v i
+eval' f v (Let lhs rhs e) = f (vpush lhs (f v rhs) v) e
+
+applyOper :: Oper (t -> t') -> t -> t'
+applyOper (Add t) (x, y) | NumDict <- reifyNum t = x + y
+applyOper (Mul t) (x, y) | NumDict <- reifyNum t = x * y
+applyOper Round x = round x