backup

expression.go

@@ -235,6 +235,11 @@ type Symbol struct {
 	expr Expression
 }
 
+type Param struct {
+	id *Identifier
+	t  Type
+}
+
 func (v *Symbol) Step() (Expression, error) {
 	if v.expr == nil {
 		return nil, fmt.Errorf("unbound symbol %s at %s", v.id, v.id.position)