diff --git a/stdlib/src/sync.rs b/stdlib/src/sync.rs
index 36ec88f4..7028188a 100644
--- a/stdlib/src/sync.rs
+++ b/stdlib/src/sync.rs
@@ -34,74 +34,75 @@ impl ScriptMutex {
     }
 }
 
+fn make_mutex_fn() -> Rc<dyn techscript_runtime::function::Callable> {
+    Rc::new(StdFunction {
+        name: "make_mutex".to_string(),
+        arity: 0,
+        callback: |ctx, _args| {
+            let mutex = ScriptMutex::new();
+            let handle_id = ctx.resources.borrow_mut().insert(mutex);
+            let mut map = IndexMap::new();
+            map.insert("_handle".to_string(), RuntimeValue::Int(handle_id as i64));
+            Ok(RuntimeValue::Map {
+                entries: Rc::new(RefCell::new(map)),
+                is_const: false,
+            })
+        },
+    })
+}
+
+fn mutex_lock_fn() -> Rc<dyn techscript_runtime::function::Callable> {
+    Rc::new(StdFunction {
+        name: "mutex_lock".to_string(),
+        arity: 1,
+        callback: |ctx, args| {
+            if let RuntimeValue::Map { entries, .. } = &args[0] {
+                let handle_id = entries
+                    .borrow()
+                    .get("_handle")
+                    .cloned()
+                    .unwrap_or(RuntimeValue::Null)
+                    .try_into_int()? as u32;
+                let resources = ctx.resources.borrow();
+                if let Some(mutex) = resources.get::<ScriptMutex>(handle_id) {
+                    mutex.lock();
+                }
+            }
+            Ok(RuntimeValue::Null)
+        },
+    })
+}
+
+fn mutex_unlock_fn() -> Rc<dyn techscript_runtime::function::Callable> {
+    Rc::new(StdFunction {
+        name: "mutex_unlock".to_string(),
+        arity: 1,
+        callback: |ctx, args| {
+            if let RuntimeValue::Map { entries, .. } = &args[0] {
+                let handle_id = entries
+                    .borrow()
+                    .get("_handle")
+                    .cloned()
+                    .unwrap_or(RuntimeValue::Null)
+                    .try_into_int()? as u32;
+                let resources = ctx.resources.borrow();
+                if let Some(mutex) = resources.get::<ScriptMutex>(handle_id) {
+                    mutex.unlock();
+                }
+            }
+            Ok(RuntimeValue::Null)
+        },
+    })
+}
+
 impl StdlibRegistry {
     pub fn register_sync(&mut self) {
         let mut exports: HashMap<String, Rc<dyn techscript_runtime::function::Callable>> =
             HashMap::new();
 
-        exports.insert(
-            "make_mutex".to_string(),
-            Rc::new(StdFunction {
-                name: "make_mutex".to_string(),
-                arity: 0,
-                callback: |ctx, _args| {
-                    let mutex = ScriptMutex::new();
-                    let handle_id = ctx.resources.borrow_mut().insert(mutex);
-                    let mut map = IndexMap::new();
-                    map.insert("_handle".to_string(), RuntimeValue::Int(handle_id as i64));
-                    Ok(RuntimeValue::Map {
-                        entries: Rc::new(RefCell::new(map)),
-                        is_const: false,
-                    })
-                },
-            }),
-        );
-
-        exports.insert(
-            "mutex_lock".to_string(),
-            Rc::new(StdFunction {
-                name: "mutex_lock".to_string(),
-                arity: 1,
-                callback: |ctx, args| {
-                    if let RuntimeValue::Map { entries, .. } = &args[0] {
-                        let handle_id = entries
-                            .borrow()
-                            .get("_handle")
-                            .cloned()
-                            .unwrap_or(RuntimeValue::Null)
-                            .try_into_int()? as u32;
-                        let resources = ctx.resources.borrow();
-                        if let Some(mutex) = resources.get::<ScriptMutex>(handle_id) {
-                            mutex.lock();
-                        }
-                    }
-                    Ok(RuntimeValue::Null)
-                },
-            }),
-        );
-
-        exports.insert(
-            "mutex_unlock".to_string(),
-            Rc::new(StdFunction {
-                name: "mutex_unlock".to_string(),
-                arity: 1,
-                callback: |ctx, args| {
-                    if let RuntimeValue::Map { entries, .. } = &args[0] {
-                        let handle_id = entries
-                            .borrow()
-                            .get("_handle")
-                            .cloned()
-                            .unwrap_or(RuntimeValue::Null)
-                            .try_into_int()? as u32;
-                        let resources = ctx.resources.borrow();
-                        if let Some(mutex) = resources.get::<ScriptMutex>(handle_id) {
-                            mutex.unlock();
-                        }
-                    }
-                    Ok(RuntimeValue::Null)
-                },
-            }),
-        );
+        exports.insert("make_mutex".to_string(), make_mutex_fn());
+        exports.insert("mutex_lock".to_string(), mutex_lock_fn());
+        exports.insert("mutex_unlock".to_string(), mutex_unlock_fn());
 
         self.register_module(
             "std.sync",