diff --git a/Source/Modules/InputHandler_Core.swift b/Source/Modules/InputHandler_Core.swift
index c4cb8250..6ac00fe4 100644
--- a/Source/Modules/InputHandler_Core.swift
+++ b/Source/Modules/InputHandler_Core.swift
@@ -320,7 +320,7 @@ public class InputHandler: InputHandlerProtocol {
           key: newestSuggestedCandidate.0, value: newestSuggestedCandidate.1.value
         )
         vCLog(
-          "UOM: Suggestion retrieved, overriding the node score of the selected candidate: \(suggestedPair.toNGramKey)")
+          "UOM: Suggestion received, overriding the node score of the selected candidate: \(suggestedPair.toNGramKey)")
         if !compositor.overrideCandidate(suggestedPair, at: cursorForCandidate, overrideType: overrideBehavior) {
           compositor.overrideCandidateLiteral(
             newestSuggestedCandidate.1.value, at: cursorForCandidate, overrideType: overrideBehavior
@@ -336,13 +336,8 @@ public class InputHandler: InputHandlerProtocol {
   // MARK: - Extracted methods and functions (Tekkon).
 
   /// 獲取與當前注音排列或拼音輸入種類有關的標點索引鍵，以英數下畫線「_」結尾。
-  var currentKeyboardParser: String {
-    currentKeyboardParserType.name + "_"
-  }
-
-  var currentKeyboardParserType: KeyboardParser {
-    .init(rawValue: prefs.keyboardParser) ?? .ofStandard
-  }
+  var currentKeyboardParser: String { currentKeyboardParserType.name + "_" }
+  var currentKeyboardParserType: KeyboardParser { .init(rawValue: prefs.keyboardParser) ?? .ofStandard }
 
   /// 給注拼槽指定注音排列或拼音輸入種類之後，將注拼槽內容清空。
   public func ensureKeyboardParser() {
@@ -400,9 +395,7 @@ public class InputHandler: InputHandlerProtocol {
   /// - Parameter input: 輸入的按鍵訊號。
   /// - Returns: 生成的標點符號索引鍵。
   func generatePunctuationNamePrefix(withKeyCondition input: InputSignalProtocol) -> String {
-    if prefs.halfWidthPunctuationEnabled {
-      return "_half_punctuation_"
-    }
+    if prefs.halfWidthPunctuationEnabled { return "_half_punctuation_" }
     switch (input.isControlHold, input.isOptionHold) {
       case (true, true): return "_alt_ctrl_punctuation_"
       case (true, false): return "_ctrl_punctuation_"
@@ -430,9 +423,7 @@ extension InputHandler {
       compositor.width > compositorWidthLimit,
       let identifier = delegate?.clientBundleIdentifier,
       prefs.clientsIMKTextInputIncapable.contains(identifier)
-    else {
-      return ""
-    }
+    else { return "" }
     // 回頭在這裡插上對 Steam 的 Client Identifier 的要求。
     var textToCommit = ""
     while compositor.width > compositorWidthLimit {
@@ -447,13 +438,9 @@ extension InputHandler {
       }
       let newCursor = max(compositor.cursor - delta, 0)
       compositor.cursor = 0
-      if !node.isReadingMismatched {
-        consolidateCursorContext(with: node.currentPair)
-      }
+      if !node.isReadingMismatched { consolidateCursorContext(with: node.currentPair) }
       // 威注音不支援 Bigram，所以無須考慮前後節點「是否需要鞏固」。
-      for _ in 0..<delta {
-        compositor.dropKey(direction: .front)
-      }
+      for _ in 0..<delta { compositor.dropKey(direction: .front) }
       compositor.cursor = newCursor
       walk()
     }
diff --git a/Source/Modules/InputHandler_HandleCandidate.swift b/Source/Modules/InputHandler_HandleCandidate.swift
index 9f94f09c..ad8b2ba2 100644
--- a/Source/Modules/InputHandler_HandleCandidate.swift
+++ b/Source/Modules/InputHandler_HandleCandidate.swift
@@ -193,9 +193,7 @@ extension InputHandler {
     if input.isSymbolMenuPhysicalKey {
       var updated = true
       updated = input.isShiftHold ? ctlCandidate.showPreviousLine() : ctlCandidate.showNextLine()
-      if !updated {
-        delegate.callError("66F3477B")
-      }
+      if !updated { delegate.callError("66F3477B") }
       return true
     }
 
diff --git a/Source/Modules/InputHandler_HandleComposition.swift b/Source/Modules/InputHandler_HandleComposition.swift
index 6ae0343e..8813f65f 100644
--- a/Source/Modules/InputHandler_HandleComposition.swift
+++ b/Source/Modules/InputHandler_HandleComposition.swift
@@ -17,6 +17,14 @@ extension InputHandler {
   ///   - input: 輸入訊號。
   /// - Returns: 告知 IMK「該按鍵是否已經被輸入法攔截處理」。
   func handleComposition(input: InputSignalProtocol) -> Bool? {
+    handlePhonabetComposition(input: input)
+  }
+
+  /// 用來處理 InputHandler.HandleInput() 當中的與注音输入有關的組字行為。
+  /// - Parameters:
+  ///   - input: 輸入訊號。
+  /// - Returns: 告知 IMK「該按鍵是否已經被輸入法攔截處理」。
+  private func handlePhonabetComposition(input: InputSignalProtocol) -> Bool? {
     guard let delegate = delegate else { return nil }
 
     // MARK: 注音按鍵輸入處理 (Handle BPMF Keys)
diff --git a/Source/Modules/InputHandler_HandleInput.swift b/Source/Modules/InputHandler_HandleInput.swift
index f2091cfd..3661f1ad 100644
--- a/Source/Modules/InputHandler_HandleInput.swift
+++ b/Source/Modules/InputHandler_HandleInput.swift
@@ -68,7 +68,6 @@ extension InputHandler {
 
       // 將整個組字區的內容遞交給客體應用。
       delegate.switchState(IMEState.ofCommitting(textToCommit: inputText.lowercased()))
-      delegate.switchState(IMEState.ofEmpty())
 
       return true
     }
@@ -79,21 +78,15 @@ extension InputHandler {
     // 不然、使用 Cocoa 內建的 flags 的話，會誤傷到在主鍵盤區域的功能鍵。
     // 我們先規定允許小鍵盤區域操縱選字窗，其餘場合一律直接放行。
     if input.isNumericPadKey {
-      if !(state.type == .ofCandidates || state.type == .ofAssociates
-        || state.type == .ofSymbolTable)
-      {
-        delegate.switchState(IMEState.ofEmpty())
+      if ![.ofCandidates, .ofAssociates, .ofSymbolTable].contains(state.type) {
         delegate.switchState(IMEState.ofCommitting(textToCommit: inputText.lowercased()))
-        delegate.switchState(IMEState.ofEmpty())
         return true
       }
     }
 
     // MARK: 處理候選字詞 (Handle Candidates)
 
-    if [.ofCandidates, .ofSymbolTable].contains(state.type) {
-      return handleCandidate(input: input)
-    }
+    if [.ofCandidates, .ofSymbolTable].contains(state.type) { return handleCandidate(input: input) }
 
     // MARK: 處理聯想詞 (Handle Associated Phrases)
 
@@ -132,7 +125,6 @@ extension InputHandler {
               delegate.switchState(IMEState.ofCommitting(textToCommit: displayedText))
             }
             delegate.switchState(IMEState.ofCommitting(textToCommit: " "))
-            delegate.switchState(IMEState.ofEmpty())
           } else if currentLM.hasUnigramsFor(key: " ") {
             compositor.insertKey(" ")
             walk()
@@ -147,12 +139,9 @@ extension InputHandler {
           return handleInlineCandidateRotation(reverseOrder: input.isCommandHold)
         }
       }
+      // 開始決定是否切換至選字狀態。
       let candidateState: IMEStateProtocol = generateStateOfCandidates()
-      if candidateState.candidates.isEmpty {
-        delegate.callError("3572F238")
-      } else {
-        delegate.switchState(candidateState)
-      }
+      _ = candidateState.candidates.isEmpty ? delegate.callError("3572F238") : delegate.switchState(candidateState)
       return true
     }
 
@@ -199,12 +188,9 @@ extension InputHandler {
             var inputting = generateStateOfInputting()
             inputting.textToCommit = textToCommit
             delegate.switchState(inputting)
-            let candidateState = generateStateOfCandidates()
-            if candidateState.candidates.isEmpty {
-              delegate.callError("B5127D8A")
-            } else {
-              delegate.switchState(candidateState)
-            }
+            // 開始決定是否切換至選字狀態。
+            let newState = generateStateOfCandidates()
+            _ = newState.candidates.isEmpty ? delegate.callError("B5127D8A") : delegate.switchState(newState)
           } else {  // 不要在注音沒敲完整的情況下叫出統合符號選單。
             delegate.callError("17446655")
           }
@@ -212,9 +198,7 @@ extension InputHandler {
         }
       } else {
         // 得在這裡先 commit buffer，不然會導致「在摁 ESC 離開符號選單時會重複輸入上一次的組字區的內容」的不當行為。
-        // 於是這裡用「模擬一次 Enter 鍵的操作」使其代為執行這個 commit buffer 的動作。
-        // 這裡不需要該函式所傳回的 bool 結果，所以用「_ =」解消掉。
-        _ = handleEnter()
+        delegate.switchState(IMEState.ofCommitting(textToCommit: state.displayedText))
         delegate.switchState(IMEState.ofSymbolTable(node: CandidateNode.root))
         return true
       }
@@ -224,13 +208,10 @@ extension InputHandler {
 
     if state.type == .ofEmpty {
       if input.isMainAreaNumKey, input.modifierFlags == [.shift, .option] {
-        guard let stringRAW = input.mainAreaNumKeyChar else { return false }
-        let newStringFW = stringRAW.applyingTransform(.fullwidthToHalfwidth, reverse: true) ?? stringRAW
-        let newStringHW = stringRAW.applyingTransform(.fullwidthToHalfwidth, reverse: false) ?? stringRAW
-        delegate.switchState(
-          IMEState.ofCommitting(textToCommit: prefs.halfWidthPunctuationEnabled ? newStringHW : newStringFW)
-        )
-        delegate.switchState(IMEState.ofEmpty())
+        guard let strRAW = input.mainAreaNumKeyChar else { return false }
+        let newString =
+          strRAW.applyingTransform(.fullwidthToHalfwidth, reverse: !prefs.halfWidthPunctuationEnabled) ?? strRAW
+        delegate.switchState(IMEState.ofCommitting(textToCommit: newString))
         return true
       }
     }
@@ -240,23 +221,15 @@ extension InputHandler {
     /// 如果仍無匹配結果的話，先看一下：
     /// - 是否是針對當前注音排列/拼音輸入種類專門提供的標點符號。
     /// - 是否是需要摁修飾鍵才可以輸入的那種標點符號。
-
     let punctuationNamePrefix: String = generatePunctuationNamePrefix(withKeyCondition: input)
     let parser = currentKeyboardParser
     let arrCustomPunctuations: [String] = [punctuationNamePrefix, parser, input.text]
     let customPunctuation: String = arrCustomPunctuations.joined()
-    if handlePunctuation(customPunctuation) {
-      return true
-    }
-
+    if handlePunctuation(customPunctuation) { return true }
     /// 如果仍無匹配結果的話，看看這個輸入是否是不需要修飾鍵的那種標點鍵輸入。
-
     let arrPunctuations: [String] = [punctuationNamePrefix, input.text]
     let punctuation: String = arrPunctuations.joined()
-
-    if handlePunctuation(punctuation) {
-      return true
-    }
+    if handlePunctuation(punctuation) { return true }
 
     // MARK: 全形/半形空白 (Full-Width / Half-Width Space)
 
@@ -264,7 +237,6 @@ extension InputHandler {
     if state.type == .ofEmpty {
       if input.isSpace, !input.isOptionHold, !input.isControlHold, !input.isCommandHold {
         delegate.switchState(IMEState.ofCommitting(textToCommit: input.isShiftHold ? "　" : " "))
-        delegate.switchState(IMEState.ofEmpty())
         return true
       }
     }
@@ -275,15 +247,10 @@ extension InputHandler {
       if input.isShiftHold {  // 這裡先不要判斷 isOptionHold。
         switch prefs.upperCaseLetterKeyBehavior {
           case 1:
-            delegate.switchState(IMEState.ofEmpty())
             delegate.switchState(IMEState.ofCommitting(textToCommit: inputText.lowercased()))
-            delegate.switchState(IMEState.ofEmpty())
             return true
-
           case 2:
-            delegate.switchState(IMEState.ofEmpty())
             delegate.switchState(IMEState.ofCommitting(textToCommit: inputText.uppercased()))
-            delegate.switchState(IMEState.ofEmpty())
             return true
           default:  // 包括 case 0，直接塞給組字區。
             let letter = "_letter_\(inputText)"
@@ -301,8 +268,7 @@ extension InputHandler {
     /// 砍掉這一段會導致「F1-F12 按鍵干擾組字區」的問題。
     /// 暫時只能先恢復這段，且補上偵錯彙報機制，方便今後排查故障。
     if state.hasComposition || !composer.isEmpty {
-      delegate.callError(
-        "Blocked data: charCode: \(input.charCode), keyCode: \(input.keyCode)")
+      delegate.callError("Blocked data: charCode: \(input.charCode), keyCode: \(input.keyCode)")
       delegate.callError("A9BFF20E")
       delegate.switchState(state)
       return true
diff --git a/Source/Modules/InputHandler_States.swift b/Source/Modules/InputHandler_States.swift
index 31fb5e27..95e4793c 100644
--- a/Source/Modules/InputHandler_States.swift
+++ b/Source/Modules/InputHandler_States.swift
@@ -252,7 +252,6 @@ extension InputHandler {
         clear()  // 這句不要砍，因為下文可能會回呼 candidateState。
         if let candidateToCommit: (String, String) = candidateState.candidates.first, !candidateToCommit.1.isEmpty {
           delegate.switchState(IMEState.ofCommitting(textToCommit: candidateToCommit.1))
-          delegate.switchState(IMEState.ofEmpty())
         } else {
           delegate.switchState(candidateState)
         }
@@ -265,13 +264,12 @@ extension InputHandler {
 
   /// Enter 鍵的處理。
   /// - Returns: 將按鍵行為「是否有處理掉」藉由 SessionCtl 回報給 IMK。
-  func handleEnter() -> Bool {
+  @discardableResult func handleEnter() -> Bool {
     guard let delegate = delegate else { return false }
     let state = delegate.state
     guard state.type == .ofInputting else { return false }
 
     delegate.switchState(IMEState.ofCommitting(textToCommit: state.displayedText))
-    delegate.switchState(IMEState.ofEmpty())
     return true
   }
 
@@ -295,7 +293,6 @@ extension InputHandler {
     }
 
     delegate.switchState(IMEState.ofCommitting(textToCommit: displayedText))
-    delegate.switchState(IMEState.ofEmpty())
     return true
   }
 
@@ -327,7 +324,6 @@ extension InputHandler {
     }
 
     delegate.switchState(IMEState.ofCommitting(textToCommit: composed))
-    delegate.switchState(IMEState.ofEmpty())
     return true
   }
 
@@ -432,9 +428,7 @@ extension InputHandler {
     guard let delegate = delegate else { return false }
     let state = delegate.state
     guard state.type == .ofInputting else { return false }
-    if !composer.isEmpty {
-      delegate.callError("9B6F908D")
-    }
+    if !composer.isEmpty { delegate.callError("9B6F908D") }
     delegate.switchState(state)
     return true
   }
@@ -616,9 +610,7 @@ extension InputHandler {
         delegate.switchState(state)
       }
     } else if input.isOptionHold {
-      if input.isControlHold {
-        return handleHome()
-      }
+      if input.isControlHold { return handleHome() }
       // 游標跳轉動作無論怎樣都會執行，但如果出了執行失敗的結果的話則觸發報錯流程。
       if !compositor.jumpCursorBySpan(to: .rear) {
         delegate.callError("8D50DD9E")