diff --git a/Source/Modules/InputHandler_Core.swift b/Source/Modules/InputHandler_Core.swift
index 05d449a1..84205ed9 100644
--- a/Source/Modules/InputHandler_Core.swift
+++ b/Source/Modules/InputHandler_Core.swift
@@ -22,6 +22,7 @@ public protocol InputHandlerProtocol {
   var currentUOM: vChewingLM.LMUserOverride { get set }
   var delegate: InputHandlerDelegate? { get set }
   var composer: Tekkon.Composer { get set }
+  var isCompositorEmpty: Bool { get }
   var isComposerUsingPinyin: Bool { get }
   func clear()
   func clearComposerAndCalligrapher()
@@ -90,6 +91,8 @@ public class InputHandler: InputHandlerProtocol {
 
   // MARK: - Functions dealing with Megrez.
 
+  public var isCompositorEmpty: Bool { compositor.isEmpty }
+
   /// 獲取當前標記得範圍。這個函式只能是函式、而非只讀變數。
   /// - Returns: 當前標記範圍。
   func currentMarkedRange() -> Range<Int> {