diff --git a/Packages/vChewing_Megrez/Sources/Megrez/1_Compositor.swift b/Packages/vChewing_Megrez/Sources/Megrez/1_Compositor.swift
index 73bc5469..68ebb30e 100644
--- a/Packages/vChewing_Megrez/Sources/Megrez/1_Compositor.swift
+++ b/Packages/vChewing_Megrez/Sources/Megrez/1_Compositor.swift
@@ -3,8 +3,6 @@
 // ====================
 // This code is released under the MIT license (SPDX-License-Identifier: MIT)
 
-import Foundation
-
 public extension Megrez {
   /// 一個組字器用來在給定一系列的索引鍵的情況下（藉由一系列的觀測行為）返回一套資料值。
   ///
@@ -186,7 +184,7 @@ public extension Megrez {
     /// 生成用以交給 GraphViz 診斷的資料檔案內容，純文字。
     public var dumpDOT: String {
       // C# StringBuilder 與 Swift NSMutableString 能提供爆發性的效能。
-      let strOutput: NSMutableString = .init(string: "digraph {\ngraph [ rankdir=LR ];\nBOS;\n")
+      var strOutput = "digraph {\ngraph [ rankdir=LR ];\nBOS;\n"
       spans.enumerated().forEach { p, span in
         (0 ... span.maxLength).forEach { ni in
           guard let np = span[ni] else { return }
diff --git a/Packages/vChewing_Megrez/Sources/Megrez/2_Walker.swift b/Packages/vChewing_Megrez/Sources/Megrez/2_Walker.swift
index 366bc137..d3f771f4 100644
--- a/Packages/vChewing_Megrez/Sources/Megrez/2_Walker.swift
+++ b/Packages/vChewing_Megrez/Sources/Megrez/2_Walker.swift
@@ -12,73 +12,118 @@ public extension Megrez.Compositor {
   /// 的路徑（所以要找最大的權重），因為在對數概率下，較大的數值意味著較大的概率。
   /// 對於 `G = (V, E)`，該算法的運行次數為 `O(|V|+|E|)`，其中 `G` 是一個有向無環圖。
   /// 這意味著，即使軌格很大，也可以用很少的算力就可以爬軌。
+  ///
+  /// - Remark: 利用該數學方法進行輸入法智能組句的（已知可考的）最開始的案例是
+  /// 郭家寶（ByVoid）的《[基於統計語言模型的拼音輸入法](https://byvoid.com/zht/blog/slm_based_pinyin_ime/) 》；
+  /// 再後來則是 2022 年中時期劉燈的 Gramambular 2 組字引擎。
   /// - Returns: 爬軌結果＋該過程是否順利執行。
-  @discardableResult mutating func walk() -> (walkedNodes: [Megrez.Node], succeeded: Bool) {
-    var result = [Megrez.Node]()
-    defer { walkedNodes = result }
-    guard !spans.isEmpty else { return (result, true) }
+  @discardableResult mutating func walk() -> [Megrez.Node] {
+    defer { Self.reinitVertexNetwork() }
+    sortAndRelax()
+    guard !spans.isEmpty else { return [] }
+    var iterated: Megrez.Node? = Megrez.Node.leadingNode
+    walkedNodes.removeAll()
+    while let itPrev = iterated?.prev {
+      // 此處必須得是 Copy，讓組字器外部對此的操作影響不到組字器內部的節點。
+      walkedNodes.insert(itPrev.copy, at: 0)
+      iterated = itPrev
+    }
+    iterated?.destroyVertex()
+    iterated = nil
+    walkedNodes.removeFirst()
+    return walkedNodes
+  }
 
-    var vertexSpans: [[Int: Vertex]] = spans.map(\.asVertexSpan)
-
-    let terminal = Vertex(node: .init(keyArray: ["_TERMINAL_"]))
-    var root = Vertex(node: .init(keyArray: ["_ROOT_"]))
-    root.distance = 0
-
-    vertexSpans.enumerated().forEach { location, vertexSpan in
-      vertexSpan.values.forEach { vertex in
-        let nextVertexPosition = location + vertex.node.spanLength
-        if nextVertexPosition == vertexSpans.count {
-          vertex.edges.append(terminal)
+  /// 先進行位相幾何排序、再卸勁。
+  internal func sortAndRelax() {
+    Self.reinitVertexNetwork()
+    guard !spans.isEmpty else { return }
+    Megrez.Node.trailingNode.distance = 0
+    spans.enumerated().forEach { location, theSpan in
+      theSpan.values.forEach { theNode in
+        let nextVertexPosition = location + theNode.spanLength
+        if nextVertexPosition == spans.count {
+          theNode.edges.append(.leadingNode)
           return
         }
-        vertexSpans[nextVertexPosition].values.forEach { vertex.edges.append($0) }
+        spans[nextVertexPosition].values.forEach { theNode.edges.append($0) }
       }
     }
-
-    root.edges.append(contentsOf: vertexSpans[0].values)
-
-    topologicalSort(root: &root).reversed().forEach { neta in
-      neta.edges.indices.forEach { neta.relax(target: &neta.edges[$0]) }
+    Megrez.Node.trailingNode.edges.append(contentsOf: spans[0].values)
+    Self.topologicalSort().reversed().forEach { neta in
+      neta.edges.indices.forEach { Self.relax(u: neta, v: &neta.edges[$0]) }
     }
-
-    var iterated = terminal
-    var walked = [Megrez.Node]()
-    var totalLengthOfKeys = 0
-
-    while let itPrev = iterated.prev {
-      walked.append(itPrev.node)
-      iterated = itPrev
-      totalLengthOfKeys += iterated.node.spanLength
-    }
-
-    // 清理內容，否則會有記憶體洩漏。
-    vertexSpans.removeAll()
-    iterated.destroy()
-    root.destroy()
-    terminal.destroy()
-
-    guard totalLengthOfKeys == keys.count else {
-      print("!!! ERROR A")
-      return (result, false)
-    }
-    guard walked.count >= 2 else {
-      print("!!! ERROR B")
-      return (result, false)
-    }
-    walked = walked.reversed()
-    walked.removeFirst()
-    result = walked
-    return (result, true)
   }
-}
 
-extension Megrez.SpanUnit {
-  /// 將當前幅位單元由節點辭典轉為頂點辭典。
-  var asVertexSpan: [Int: Megrez.Compositor.Vertex] {
-    var result = [Int: Megrez.Compositor.Vertex]()
-    forEach { theKey, theValue in
-      result[theKey] = .init(node: theValue)
+  /// 摧毀所有與共用起始虛擬節點有牽涉的節點自身的 Vertex 特性資料。
+  internal static func reinitVertexNetwork() {
+    Megrez.Node.trailingNode.destroyVertex()
+    Megrez.Node.leadingNode.destroyVertex()
+  }
+
+  /// 對持有單個根頂點的有向無環圖進行位相幾何排序（topological
+  /// sort）、且將排序結果以頂點陣列的形式給出。
+  ///
+  /// 這裡使用我們自己的堆棧和狀態定義實現了一個非遞迴版本，
+  /// 這樣我們就不會受到當前線程的堆棧大小的限制。以下是等價的原始算法。
+  /// ```
+  ///  func topologicalSort(node: Node) {
+  ///    node.edges.forEach { nodeNode in
+  ///      if !nodeNode.topologicallySorted {
+  ///        dfs(nodeNode, result)
+  ///        nodeNode.topologicallySorted = true
+  ///      }
+  ///      result.append(nodeNode)
+  ///    }
+  ///  }
+  /// ```
+  /// 至於其遞迴版本，則類似於 Cormen 在 2001 年的著作「Introduction to Algorithms」當中的樣子。
+  /// - Returns: 排序結果（頂點陣列）。
+  private static func topologicalSort() -> [Megrez.Node] {
+    class State {
+      var iterIndex: Int
+      let node: Megrez.Node
+      init(node: Megrez.Node, iterIndex: Int = 0) {
+        self.node = node
+        self.iterIndex = iterIndex
+      }
+    }
+    var result = [Megrez.Node]()
+    var stack = [State]()
+    stack.append(.init(node: .trailingNode))
+    while !stack.isEmpty {
+      let state = stack[stack.count - 1]
+      let theNode = state.node
+      if state.iterIndex < state.node.edges.count {
+        let newNode = state.node.edges[state.iterIndex]
+        state.iterIndex += 1
+        if !newNode.topologicallySorted {
+          stack.append(.init(node: newNode))
+          continue
+        }
+      }
+      theNode.topologicallySorted = true
+      result.append(theNode)
+      stack.removeLast()
     }
     return result
   }
+
+  /// 卸勁函式。
+  ///
+  /// 「卸勁 (relax)」一詞出自 Cormen 在 2001 年的著作「Introduction to Algorithms」的 585 頁。
+  /// - Remark: 自己就是參照頂點 (u)，會在必要時成為 target (v) 的前述頂點。
+  /// - Parameters:
+  ///   - u: 基準頂點。
+  ///   - v: 要影響的頂點。
+  private static func relax(u: Megrez.Node, v: inout Megrez.Node) {
+    // 從 u 到 w 的距離，也就是 v 的權重。
+    let w: Double = v.score
+    // 這裡計算最大權重：
+    // 如果 v 目前的距離值小於「u 的距離值＋w（w 是 u 到 w 的距離，也就是 v 的權重）」，
+    // 我們就更新 v 的距離及其前述頂點。
+    guard v.distance < u.distance + w else { return }
+    v.distance = u.distance + w
+    v.prev = u
+  }
 }
diff --git a/Packages/vChewing_Megrez/Sources/Megrez/3_KeyValuePaired.swift b/Packages/vChewing_Megrez/Sources/Megrez/3_KeyValuePaired.swift
index bf20e4cb..19d839a2 100644
--- a/Packages/vChewing_Megrez/Sources/Megrez/3_KeyValuePaired.swift
+++ b/Packages/vChewing_Megrez/Sources/Megrez/3_KeyValuePaired.swift
@@ -3,54 +3,64 @@
 // ====================
 // This code is released under the MIT license (SPDX-License-Identifier: MIT)
 
-import Foundation
-
 public extension Megrez {
   /// 鍵值配對，乃索引鍵陣列與讀音的配對單元。
-  struct KeyValuePaired: Equatable, Hashable, Comparable, CustomStringConvertible {
+  class KeyValuePaired: Unigram, Comparable {
     /// 索引鍵陣列。一般情況下用來放置讀音等可以用來作為索引的內容。
-    public var keyArray: [String]
-    /// 資料值。
-    public var value: String
+    public var keyArray: [String] = []
     /// 將當前鍵值列印成一個字串。
-    public var description: String { "(" + keyArray.description + "," + value + ")" }
+    override public var description: String { "(\(keyArray.description),\(value),\(score))" }
     /// 判斷當前鍵值配對是否合規。如果鍵與值有任一為空，則結果為 false。
     public var isValid: Bool { !keyArray.joined().isEmpty && !value.isEmpty }
     /// 將當前鍵值列印成一個字串，但如果該鍵值配對為空的話則僅列印「()」。
-    public var toNGramKey: String { !isValid ? "()" : "(" + joinedKey() + "," + value + ")" }
+    public var toNGramKey: String { !isValid ? "()" : "(\(joinedKey()),\(value))" }
     /// 通用陣列表達形式。
-    public var tupletExpression: (keyArray: [String], value: String) { (keyArray, value) }
+    public var keyValueTuplet: (keyArray: [String], value: String) { (keyArray, value) }
+    /// 通用陣列表達形式。
+    public var triplet: (keyArray: [String], value: String, score: Double) { (keyArray, value, score) }
 
     /// 初期化一組鍵值配對。
     /// - Parameters:
     ///   - keyArray: 索引鍵陣列。一般情況下用來放置讀音等可以用來作為索引的內容。
     ///   - value: 資料值。
-    public init(keyArray: [String], value: String = "N/A") {
+    ///   - score: 權重（雙精度小數）。
+    public init(keyArray: [String], value: String = "N/A", score: Double = 0) {
+      super.init(value: value.isEmpty ? "N/A" : value, score: score)
       self.keyArray = keyArray.isEmpty ? ["N/A"] : keyArray
-      self.value = value.isEmpty ? "N/A" : value
     }
 
     /// 初期化一組鍵值配對。
-    /// - Parameter tupletExpression: 傳入的通用陣列表達形式。
+    /// - Parameter tripletExpression: 傳入的通用陣列表達形式。
+    public init(_ tripletExpression: (keyArray: [String], value: String, score: Double)) {
+      let theValue = tripletExpression.value.isEmpty ? "N/A" : tripletExpression.value
+      super.init(value: theValue, score: tripletExpression.score)
+      keyArray = tripletExpression.keyArray.isEmpty ? ["N/A"] : tripletExpression.keyArray
+    }
+
+    /// 初期化一組鍵值配對。
+    /// - Parameter tuplet: 傳入的通用陣列表達形式。
     public init(_ tupletExpression: (keyArray: [String], value: String)) {
+      let theValue = tupletExpression.value.isEmpty ? "N/A" : tupletExpression.value
+      super.init(value: theValue, score: 0)
       keyArray = tupletExpression.keyArray.isEmpty ? ["N/A"] : tupletExpression.keyArray
-      value = tupletExpression.value.isEmpty ? "N/A" : tupletExpression.value
     }
 
     /// 初期化一組鍵值配對。
     /// - Parameters:
     ///   - key: 索引鍵。一般情況下用來放置讀音等可以用來作為索引的內容。
     ///   - value: 資料值。
-    public init(key: String = "N/A", value: String = "N/A") {
-      keyArray = key.isEmpty ? ["N/A"] : key.components(separatedBy: Megrez.Compositor.theSeparator)
-      self.value = value.isEmpty ? "N/A" : value
+    ///   - score: 權重（雙精度小數）。
+    public init(key: String = "N/A", value: String = "N/A", score: Double = 0) {
+      super.init(value: value.isEmpty ? "N/A" : value, score: score)
+      keyArray = key.isEmpty ? ["N/A"] : key.sliced(by: Megrez.Compositor.theSeparator)
     }
 
     /// 做為預設雜湊函式。
     /// - Parameter hasher: 目前物件的雜湊碼。
-    public func hash(into hasher: inout Hasher) {
+    override public func hash(into hasher: inout Hasher) {
       hasher.combine(keyArray)
       hasher.combine(value)
+      hasher.combine(score)
     }
 
     public func joinedKey(by separator: String = Megrez.Compositor.theSeparator) -> String {
@@ -58,7 +68,7 @@ public extension Megrez {
     }
 
     public static func == (lhs: KeyValuePaired, rhs: KeyValuePaired) -> Bool {
-      lhs.keyArray == rhs.keyArray && lhs.value == rhs.value
+      lhs.score == rhs.score && lhs.keyArray == rhs.keyArray && lhs.value == rhs.value
     }
 
     public static func < (lhs: KeyValuePaired, rhs: KeyValuePaired) -> Bool {
@@ -193,9 +203,9 @@ public extension Megrez.Compositor {
       arrOverlappedNodes = fetchOverlappingNodes(at: i)
       arrOverlappedNodes.forEach { anchor in
         if anchor.node == overridden.node { return }
-        if !overridden.node.joinedKey(by: "\t").contains(anchor.node.joinedKey(by: "\t"))
-          || !overridden.node.value.contains(anchor.node.value)
-        {
+        let anchorNodeKeyJoined = anchor.node.joinedKey(by: "\t")
+        let overriddenNodeKeyJoined = overridden.node.joinedKey(by: "\t")
+        if !overriddenNodeKeyJoined.has(string: anchorNodeKeyJoined) || !overridden.node.value.has(string: anchor.node.value) {
           anchor.node.reset()
           return
         }
diff --git a/Packages/vChewing_Megrez/Sources/Megrez/6_Node.swift b/Packages/vChewing_Megrez/Sources/Megrez/5_Node.swift
similarity index 89%
rename from Packages/vChewing_Megrez/Sources/Megrez/6_Node.swift
rename to Packages/vChewing_Megrez/Sources/Megrez/5_Node.swift
index c4c466e5..6f008a38 100644
--- a/Packages/vChewing_Megrez/Sources/Megrez/6_Node.swift
+++ b/Packages/vChewing_Megrez/Sources/Megrez/5_Node.swift
@@ -3,8 +3,6 @@
 // ====================
 // This code is released under the MIT license (SPDX-License-Identifier: MIT)
 
-import Foundation
-
 public extension Megrez {
   /// 字詞節點。
   ///
@@ -173,6 +171,39 @@ public extension Megrez {
       }
       return false
     }
+
+    // MARK: - Vertex Extensions.
+
+    // 注意：這一段的任何參數都不參與 Hash。
+
+    /// 組字器「文字輸入方向上的」最後方的虛擬節點。
+    internal static let trailingNode = Megrez.Node(keyArray: ["$TRAILING"])
+    /// 組字器「文字輸入方向上的」最前方的虛擬節點，也是根頂點。
+    internal static let leadingNode = Megrez.Node(keyArray: ["$LEADING"])
+
+    /// 前述頂點。
+    internal var prev: Node?
+    /// 自身屬下的頂點陣列。
+    internal var edges = [Node]()
+    /// 該變數用於最短路徑的計算。
+    ///
+    /// 我們實際上是在計算具有最大權重的路徑，因此距離的初始值是負無窮的。
+    /// 如果我們要計算最短的權重/距離，我們會將其初期值設為正無窮。
+    internal var distance = -(Double.infinity)
+    /// 在進行進行位相幾何排序時會用到的狀態標記。
+    internal var topologicallySorted = false
+
+    /// 摧毀一個字詞節點本身的 Vertex 特性資料。
+    /// 讓一個 Vertex 順藤摸瓜地將自己的所有的連帶的 Vertex 都摧毀，再摧毀自己。
+    /// 此過程必須在一套 Vertex 全部使用完畢之後執行一次，可防止記憶體洩漏。
+    internal func destroyVertex() {
+      while prev?.prev != nil { prev?.destroyVertex() }
+      prev = nil
+      edges.forEach { $0.destroyVertex() }
+      edges.removeAll()
+      distance = -(Double.infinity)
+      topologicallySorted = false
+    }
   }
 }
 
@@ -256,14 +287,9 @@ public extension Array where Element == Megrez.Node {
   /// 提供一組逐字的字音配對陣列（不使用 Megrez 的 KeyValuePaired 類型），但字音不匹配的節點除外。
   var smashedPairs: [(key: String, value: String)] {
     var arrData = [(key: String, value: String)]()
-    let separator = Megrez.Compositor.theSeparator
     forEach { node in
-      if node.isReadingMismatched {
-        var newKey = node.joinedKey()
-        if !separator.isEmpty, newKey != separator, newKey.contains(separator) {
-          newKey = newKey.replacingOccurrences(of: separator, with: "\t")
-        }
-        arrData.append((key: newKey, value: node.value))
+      if node.isReadingMismatched, !node.keyArray.joined().isEmpty {
+        arrData.append((key: node.keyArray.joined(separator: "\t"), value: node.value))
         return
       }
       let arrValueChars = node.value.map(\.description)
diff --git a/Packages/vChewing_Megrez/Sources/Megrez/5_Vertex.swift b/Packages/vChewing_Megrez/Sources/Megrez/5_Vertex.swift
deleted file mode 100644
index b60ea371..00000000
--- a/Packages/vChewing_Megrez/Sources/Megrez/5_Vertex.swift
+++ /dev/null
@@ -1,109 +0,0 @@
-// Swiftified and further development by (c) 2022 and onwards The vChewing Project (MIT License).
-// Was initially rebranded from (c) Lukhnos Liu's C++ library "Gramambular 2" (MIT License).
-// ====================
-// This code is released under the MIT license (SPDX-License-Identifier: MIT)
-
-extension Megrez.Compositor {
-  /// 一個「有向無環圖的」的頂點單位。
-  ///
-  /// 這是一個可變的數據結構，用於有向無環圖的構建和單源最短路徑的計算。
-  class Vertex {
-    /// 前述頂點。
-    public var prev: Vertex?
-    /// 自身屬下的頂點陣列。
-    public var edges = [Vertex]()
-    /// 該變數用於最短路徑的計算。
-    ///
-    /// 我們實際上是在計算具有最大權重的路徑，因此距離的初始值是負無窮的。
-    /// 如果我們要計算最短的權重/距離，我們會將其初期值設為正無窮。
-    public var distance = -(Double.infinity)
-    /// 在進行進行位相幾何排序時會用到的狀態標記。
-    public var topologicallySorted = false
-    /// 字詞節點。
-    public var node: Megrez.Node
-
-    /// 初期化一個「有向無環圖的」的頂點單位。
-    ///
-    /// 這是一個可變的數據結構，用於有向無環圖的構建和單源最短路徑的計算。
-    /// - Parameter node: 字詞節點。
-    public init(node: Megrez.Node) {
-      self.node = node
-    }
-
-    /// 讓一個 Vertex 順藤摸瓜地將自己的所有的連帶的 Vertex 都摧毀，再摧毀自己。
-    /// 此過程必須在一套 Vertex 全部使用完畢之後執行一次，可防止記憶體洩漏。
-    public func destroy() {
-      while prev?.prev != nil { prev?.destroy() }
-      prev = nil
-      edges.forEach { $0.destroy() }
-      edges.removeAll()
-      node = .init()
-    }
-
-    /// 卸勁函式。
-    ///
-    /// 「卸勁 (relax)」一詞出自 Cormen 在 2001 年的著作「Introduction to Algorithms」的 585 頁。
-    /// - Remark: 自己就是參照頂點 (u)，會在必要時成為 target (v) 的前述頂點。
-    /// - Parameters:
-    ///   - target: 要影響的頂點。
-    public func relax(target: inout Vertex) {
-      // 從 u 到 w 的距離，也就是 v 的權重。
-      let w: Double = target.node.score
-      // 這裡計算最大權重：
-      // 如果 v 目前的距離值小於「u 的距離值＋w（w 是 u 到 w 的距離，也就是 v 的權重）」，
-      // 我們就更新 v 的距離及其前述頂點。
-      if target.distance >= distance + w { return }
-      target.distance = distance + w
-      target.prev = self
-    }
-  }
-
-  /// 對持有單個根頂點的有向無環圖進行位相幾何排序（topological
-  /// sort）、且將排序結果以頂點陣列的形式給出。
-  ///
-  /// 這裡使用我們自己的堆棧和狀態定義實現了一個非遞迴版本，
-  /// 這樣我們就不會受到當前線程的堆棧大小的限制。以下是等價的原始算法。
-  /// ```
-  ///  func topologicalSort(vertex: Vertex) {
-  ///    vertex.edges.forEach { vertexNode in
-  ///      if !vertexNode.topologicallySorted {
-  ///        dfs(vertexNode, result)
-  ///        vertexNode.topologicallySorted = true
-  ///      }
-  ///      result.append(vertexNode)
-  ///    }
-  ///  }
-  /// ```
-  /// 至於其遞迴版本，則類似於 Cormen 在 2001 年的著作「Introduction to Algorithms」當中的樣子。
-  /// - Parameter root: 根頂點。
-  /// - Returns: 排序結果（頂點陣列）。
-  func topologicalSort(root: inout Vertex) -> [Vertex] {
-    class State {
-      var iterIndex: Int
-      let vertex: Vertex
-      init(vertex: Vertex, iterIndex: Int = 0) {
-        self.vertex = vertex
-        self.iterIndex = iterIndex
-      }
-    }
-    var result = [Vertex]()
-    var stack = [State]()
-    stack.append(.init(vertex: root))
-    while !stack.isEmpty {
-      let state = stack[stack.count - 1]
-      let theVertex = state.vertex
-      if state.iterIndex < state.vertex.edges.count {
-        let newVertex = state.vertex.edges[state.iterIndex]
-        state.iterIndex += 1
-        if !newVertex.topologicallySorted {
-          stack.append(.init(vertex: newVertex))
-          continue
-        }
-      }
-      theVertex.topologicallySorted = true
-      result.append(theVertex)
-      stack.removeLast()
-    }
-    return result
-  }
-}
diff --git a/Packages/vChewing_Megrez/Sources/Megrez/7_LangModel.swift b/Packages/vChewing_Megrez/Sources/Megrez/6_LangModel.swift
similarity index 100%
rename from Packages/vChewing_Megrez/Sources/Megrez/7_LangModel.swift
rename to Packages/vChewing_Megrez/Sources/Megrez/6_LangModel.swift
diff --git a/Packages/vChewing_Megrez/Sources/Megrez/8_Unigram.swift b/Packages/vChewing_Megrez/Sources/Megrez/7_Unigram.swift
similarity index 96%
rename from Packages/vChewing_Megrez/Sources/Megrez/8_Unigram.swift
rename to Packages/vChewing_Megrez/Sources/Megrez/7_Unigram.swift
index cfccde05..0596fbcb 100644
--- a/Packages/vChewing_Megrez/Sources/Megrez/8_Unigram.swift
+++ b/Packages/vChewing_Megrez/Sources/Megrez/7_Unigram.swift
@@ -5,7 +5,7 @@
 
 public extension Megrez {
   /// 單元圖。
-  @frozen struct Unigram: Equatable, CustomStringConvertible, Hashable {
+  class Unigram: Equatable, CustomStringConvertible, Hashable {
     /// 資料值，通常是詞語或單個字。
     public var value: String
     /// 權重。
diff --git a/Packages/vChewing_Megrez/Sources/Megrez/8_SwiftImpl_Internals.swift b/Packages/vChewing_Megrez/Sources/Megrez/8_SwiftImpl_Internals.swift
new file mode 100644
index 00000000..65997e0e
--- /dev/null
+++ b/Packages/vChewing_Megrez/Sources/Megrez/8_SwiftImpl_Internals.swift
@@ -0,0 +1,74 @@
+// Swiftified and further development by (c) 2022 and onwards The vChewing Project (MIT License).
+// Was initially rebranded from (c) Lukhnos Liu's C++ library "Gramambular 2" (MIT License).
+// ====================
+// This code is released under the MIT license (SPDX-License-Identifier: MIT)
+
+// This package is trying to deprecate its dependency of Foundation, hence this file.
+
+extension StringProtocol {
+  func has(string target: any StringProtocol) -> Bool {
+    let selfArray = Array(unicodeScalars)
+    let targetArray = Array(target.description.unicodeScalars)
+    guard !target.isEmpty else { return isEmpty }
+    guard count >= target.count else { return false }
+    for index in 0 ..< selfArray.count {
+      let range = index ..< (Swift.min(index + targetArray.count, selfArray.count))
+      let ripped = Array(selfArray[range])
+      if ripped == targetArray { return true }
+    }
+    return false
+  }
+
+  func sliced(by separator: any StringProtocol = "") -> [String] {
+    let selfArray = Array(unicodeScalars)
+    let arrSeparator = Array(separator.description.unicodeScalars)
+    var result: [String] = []
+    var buffer: [Unicode.Scalar] = []
+    var sleepCount = 0
+    for index in 0 ..< selfArray.count {
+      let currentChar = selfArray[index]
+      let range = index ..< (Swift.min(index + arrSeparator.count, selfArray.count))
+      let ripped = Array(selfArray[range])
+      if ripped.isEmpty { continue }
+      if ripped == arrSeparator {
+        sleepCount = range.count
+        result.append(buffer.map { String($0) }.joined())
+        buffer.removeAll()
+      }
+      if sleepCount < 1 {
+        buffer.append(currentChar)
+      }
+      sleepCount -= 1
+    }
+    result.append(buffer.map { String($0) }.joined())
+    buffer.removeAll()
+    return result
+  }
+
+  func swapping(_ target: String, with newString: String) -> String {
+    let selfArray = Array(unicodeScalars)
+    let arrTarget = Array(target.description.unicodeScalars)
+    var result = ""
+    var buffer: [Unicode.Scalar] = []
+    var sleepCount = 0
+    for index in 0 ..< selfArray.count {
+      let currentChar = selfArray[index]
+      let range = index ..< (Swift.min(index + arrTarget.count, selfArray.count))
+      let ripped = Array(selfArray[range])
+      if ripped.isEmpty { continue }
+      if ripped == arrTarget {
+        sleepCount = ripped.count
+        result.append(buffer.map { String($0) }.joined())
+        result.append(newString)
+        buffer.removeAll()
+      }
+      if sleepCount < 1 {
+        buffer.append(currentChar)
+      }
+      sleepCount -= 1
+    }
+    result.append(buffer.map { String($0) }.joined())
+    buffer.removeAll()
+    return result
+  }
+}
diff --git a/Packages/vChewing_Megrez/Tests/MegrezTests/LMDataForTests.swift b/Packages/vChewing_Megrez/Tests/MegrezTests/LMDataForTests.swift
index b79ba9a1..50e181ba 100644
--- a/Packages/vChewing_Megrez/Tests/MegrezTests/LMDataForTests.swift
+++ b/Packages/vChewing_Megrez/Tests/MegrezTests/LMDataForTests.swift
@@ -19,7 +19,7 @@ class SimpleLM: LangModelProtocol {
       let col0 = String(linestream[0])
       let col1 = String(linestream[1])
       let col2 = Double(linestream[2]) ?? 0.0
-      var u = Megrez.Unigram(value: swapKeyValue ? col0 : col1, score: 0)
+      let u = Megrez.Unigram(value: swapKeyValue ? col0 : col1, score: 0)
       u.score = col2
       mutDatabase[swapKeyValue ? col1 : col0, default: []].append(u)
     }
diff --git a/Packages/vChewing_Megrez/Tests/MegrezTests/MegrezTests.swift b/Packages/vChewing_Megrez/Tests/MegrezTests/MegrezTests.swift
index 1315fd01..d8823f37 100644
--- a/Packages/vChewing_Megrez/Tests/MegrezTests/MegrezTests.swift
+++ b/Packages/vChewing_Megrez/Tests/MegrezTests/MegrezTests.swift
@@ -351,7 +351,7 @@ final class MegrezTests: XCTestCase {
     "高科技公司的年終獎金".forEach { i in
       compositor.insertKey(i.description)
     }
-    let result = compositor.walk().0
+    let result = compositor.walk()
     XCTAssertEqual(result.joinedKeys(by: ""), ["高科技", "公司", "的", "年終", "獎金"])
   }
 
@@ -384,7 +384,7 @@ final class MegrezTests: XCTestCase {
     compositor.insertKey("jiang3")
     compositor.walk()
     compositor.insertKey("jin1")
-    var result = compositor.walk().0
+    var result = compositor.walk()
     XCTAssertEqual(result.values, ["高科技", "公司", "的", "年中", "獎金"])
     XCTAssertEqual(compositor.length, 10)
     compositor.cursor = 7
@@ -394,7 +394,7 @@ final class MegrezTests: XCTestCase {
     XCTAssertTrue(candidates.contains("中"))
     XCTAssertTrue(candidates.contains("鍾"))
     XCTAssertTrue(compositor.overrideCandidateLiteral("年終", at: 7))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["高科技", "公司", "的", "年終", "獎金"])
     let candidatesBeginAt = compositor.fetchCandidates(at: 3, filter: .beginAt).map(\.value)
     let candidatesEndAt = compositor.fetchCandidates(at: 3, filter: .endAt).map(\.value)
@@ -436,11 +436,11 @@ final class MegrezTests: XCTestCase {
     compositor.insertKey("gao1")
     compositor.insertKey("ke1")
     compositor.insertKey("ji4")
-    var result = compositor.walk().0
+    var result = compositor.walk()
     XCTAssertEqual(result.values, ["高科技"])
     compositor.insertKey("gong1")
     compositor.insertKey("si1")
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["高科技", "公司"])
   }
 
@@ -450,29 +450,29 @@ final class MegrezTests: XCTestCase {
     compositor.insertKey("gao1")
     compositor.insertKey("ke1")
     compositor.insertKey("ji4")
-    var result = compositor.walk().0
+    var result = compositor.walk()
     XCTAssertEqual(result.values, ["高科技"])
     compositor.cursor = 0
     XCTAssertTrue(compositor.overrideCandidateLiteral("膏", at: compositor.cursor))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["膏", "科技"])
     XCTAssertTrue(compositor.overrideCandidateLiteral("高科技", at: 1))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["高科技"])
     XCTAssertTrue(compositor.overrideCandidateLiteral("膏", at: 0))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["膏", "科技"])
 
     XCTAssertTrue(compositor.overrideCandidateLiteral("柯", at: 1))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["膏", "柯", "際"])
 
     XCTAssertTrue(compositor.overrideCandidateLiteral("暨", at: 2))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["膏", "柯", "暨"])
 
     XCTAssertTrue(compositor.overrideCandidateLiteral("高科技", at: 3))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["高科技"])
   }
 
@@ -484,19 +484,19 @@ final class MegrezTests: XCTestCase {
     compositor.insertKey("zhong1")
     compositor.insertKey("jiang3")
     compositor.insertKey("jin1")
-    var result = compositor.walk().0
+    var result = compositor.walk()
     XCTAssertEqual(result.values, ["年中", "獎金"])
 
     XCTAssertTrue(compositor.overrideCandidateLiteral("終講", at: 1))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["年", "終講", "金"])
 
     XCTAssertTrue(compositor.overrideCandidateLiteral("槳襟", at: 2))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["年中", "槳襟"])
 
     XCTAssertTrue(compositor.overrideCandidateLiteral("年終", at: 0))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["年終", "槳襟"])
   }
 
@@ -509,16 +509,16 @@ final class MegrezTests: XCTestCase {
     compositor.insertKey("yan4")
     compositor.insertKey("wei2")
     compositor.insertKey("xian3")
-    var result = compositor.walk().0
+    var result = compositor.walk()
     XCTAssertEqual(result.values, ["高熱", "火焰", "危險"])
     let location = 2
 
     XCTAssertTrue(compositor.overrideCandidate(.init(keyArray: ["huo3"], value: "🔥"), at: location))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["高熱", "🔥", "焰", "危險"])
 
     XCTAssertTrue(compositor.overrideCandidate(.init(keyArray: ["huo3", "yan4"], value: "🔥"), at: location))
-    result = compositor.walk().0
+    result = compositor.walk()
     XCTAssertEqual(result.values, ["高熱", "🔥", "危險"])
   }
 
@@ -530,11 +530,11 @@ final class MegrezTests: XCTestCase {
     compositor.insertKey("zhong1")
     compositor.insertKey("jiang3")
     compositor.insertKey("jin1")
-    let oldResult = compositor.walk().0.values.joined()
+    let oldResult = compositor.walk().values.joined()
     print(oldResult)
     theLM.trim(key: "nian2zhong1", value: "年中")
     compositor.update(updateExisting: true)
-    let newResult = compositor.walk().0.values.joined()
+    let newResult = compositor.walk().values.joined()
     print(newResult)
     XCTAssertEqual([oldResult, newResult], ["年中獎金", "年終獎金"])
     compositor.cursor = 4
@@ -542,7 +542,7 @@ final class MegrezTests: XCTestCase {
     compositor.dropKey(direction: .rear)
     theLM.trim(key: "nian2zhong1", value: "年終")
     compositor.update(updateExisting: true)
-    let newResult2 = compositor.walk().0.values
+    let newResult2 = compositor.walk().values
     print(newResult2)
     XCTAssertEqual(newResult2, ["年", "中"])
   }
@@ -555,8 +555,8 @@ final class MegrezTests: XCTestCase {
       compositorA.insertKey(key.description)
     }
     var compositorB = compositorA.hardCopy
-    let resultA = compositorA.walk().walkedNodes
-    let resultB = compositorB.walk().walkedNodes
+    let resultA = compositorA.walk()
+    let resultB = compositorB.walk()
     XCTAssertEqual(resultA, resultB)
   }