diff --git a/schala-lang/src/eval.rs b/schala-lang/src/eval.rs
index f7ad42c..30557a1 100644
--- a/schala-lang/src/eval.rs
+++ b/schala-lang/src/eval.rs
@@ -77,7 +77,9 @@ impl Expr {
         UserDefined { name: None, .. } => format!("<function>"),
         UserDefined { name: Some(name), .. } => format!("<function {}>", name),
       },
-      Expr::Constructor { name } => format!("<constructor {}>", name),
+      Expr::NewConstructor { 
+        type_name, tag, arity,
+      } => unimplemented!(),
       Expr::Tuple(exprs) => paren_wrapped_vec(exprs),
       _ => format!("{:?}", self),
     }
diff --git a/schala-lang/src/reduced_ast.rs b/schala-lang/src/reduced_ast.rs
index 7523807..9c355cf 100644
--- a/schala-lang/src/reduced_ast.rs
+++ b/schala-lang/src/reduced_ast.rs
@@ -32,7 +32,7 @@ pub enum Expr {
   NewConstructor {
     type_name: Rc<String>,
     tag: usize,
-    arg: Box<Expression>,
+    arity: usize,
   },
   Constructor {
     name: Rc<String>,
@@ -117,8 +117,10 @@ impl Expression {
       PrefixExp(op, arg) => op.reduce(symbol_table, arg),
       Value(name) => {
         match symbol_table.values.get(name) {
-          Some(Symbol { spec: SymbolSpec::DataConstructor { type_args, .. }, .. }) => {
-            Expr::Constructor { name: name.clone() }
+          Some(Symbol { spec: SymbolSpec::DataConstructor { index, type_args, type_name}, .. }) => Expr::NewConstructor {
+            type_name: type_name.clone(),
+            tag: index.clone(),
+            arity: type_args.len(),
           },
           _ => Expr::Val(name.clone()),
         }