From 4124878e20046b3e7b79cbe5befd69ea74fb855f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=A2=B6=E5=A1=9A=E5=A4=AA=E6=99=BA?=
 <kajizukataichi@outlook.jp>
Date: Fri, 3 Jan 2025 21:44:45 +0900
Subject: [PATCH] Update main.rs

---
 src/main.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 52c6adf..7a465d1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -121,7 +121,11 @@ impl Engine {
                 (
                     "free".to_string(),
                     Type::Function(Function::BuiltIn(|name, engine| {
-                        engine.env.remove(&name.get_refer()?);
+                        let name = &name.get_refer()?;
+                        if engine.protect.contains(name) {
+                            return None;
+                        }
+                        engine.env.remove(name);
                         Some(Type::Null)
                     })),
                 ),