feat: usable?

src/bytecode.rs

@@ -1,3 +1,5 @@
+use std::fmt::{Debug, Formatter, Result};
+
 use ecow::EcoString;
 
 use crate::ty::internal::Const;
@@ -57,6 +59,8 @@ pub enum OpCode {
 
     /// push an empty attribute set onto stack
     AttrSet,
+    /// push an empty recursive attribute set onto stack
+    RecAttrSet,
     /// [ .. set value ] consume 1 element, push a static kv pair (`name`, `value`) into `set`
     PushStaticAttr { name: EcoString },
     /// [ .. set name value ] consume 2 elements, push a dynamic kv pair (`name`, `value`) in to `set`
@@ -87,15 +91,14 @@ pub enum OpCode {
     /// [ .. set sym ] select `sym` from `set`
     SelectDynamic,
     /// [ .. set sym default ] select `sym` from `set` or `default`
-
     SelectDynamicOrDefault,
     /// enter the environment of the attribute set at TOS
     EnterEnv,
     /// exit current envrironment
     LeaveEnv,
 
-    /// no operation, used as termporary placeholder
-    NoOp,
+    /// illegal operation, used as termporary placeholder
+    Illegal,
 }
 
 #[derive(Debug, Clone, Copy)]