diff --git a/src/bytecode.ts b/src/bytecode.ts
index 8554b61..be9f475 100644
--- a/src/bytecode.ts
+++ b/src/bytecode.ts
@@ -16,7 +16,7 @@ export type Constant =
   | Value
   | FunctionDef
 
-type Atom = number | string | boolean | null
+type Atom = RegExp | number | string | boolean | null
 
 type InstructionTuple =
   // Stack