Megrez // Sanitizing node-crossed candidates.

Packages/vChewing_Megrez/Sources/Megrez/3_KeyValuePaired.swift

@@ -92,28 +92,41 @@ public extension Megrez.Compositor {
 
   /// 返回在當前位置的所有候選字詞（以詞音配對的形式）。如果組字器內有幅位、且游標
   /// 位於組字器的（文字輸入順序的）最前方（也就是游標位置的數值是最大合規數值）的
-  /// 話，那麼這裡會用到 location - 1、以免去在呼叫該函式後再處理的麻煩。
-  /// - Parameter location: 游標位置。
+  /// 話，那麼這裡會對 location 的位置自動減去 1、以免去在呼叫該函式後再處理的麻煩。
+  /// - Parameter location: 游標位置，必須是顯示的游標位置、不得做任何事先糾偏處理。
   /// - Returns: 候選字音配對陣列。
-  func fetchCandidates(at location: Int, filter: CandidateFetchFilter = .all) -> [Megrez.KeyValuePaired] {
+  func fetchCandidates(
+    at givenLocation: Int? = nil, filter givenFilter: CandidateFetchFilter = .all
+  ) -> [Megrez.KeyValuePaired] {
     var result = [Megrez.KeyValuePaired]()
     guard !keys.isEmpty else { return result }
-    let location = max(min(location, keys.count - 1), 0) // 防呆
+    var location = max(min(givenLocation ?? cursor, keys.count), 0)
+    var filter = givenFilter
+    if filter == .endAt {
+      if location == keys.count { filter = .all }
+      location -= 1
+    }
+    location = max(min(location, keys.count - 1), 0)
     let anchors: [NodeAnchor] = fetchOverlappingNodes(at: location).stableSorted {
       // 按照讀音的長度（幅位長度）來給節點排序。
       $0.spanLength > $1.spanLength
     }
     let keyAtCursor = keys[location]
-    anchors.map(\.node).filter(\.keyArray.isEmpty.negative).forEach { theNode in
+    anchors.forEach { theAnchor in
+      let theNode = theAnchor.node
       theNode.unigrams.forEach { gram in
         switch filter {
         case .all:
           // 得加上這道篩選，不然會出現很多無效結果。
           if !theNode.keyArray.contains(keyAtCursor) { return }
         case .beginAt:
-          if theNode.keyArray[0] != keyAtCursor { return }
+          guard theAnchor.spanIndex == location else { return }
         case .endAt:
-          if theNode.keyArray.reversed()[0] != keyAtCursor { return }
+          guard theNode.keyArray.last == keyAtCursor else { return }
+          switch theNode.spanLength {
+          case 2... where theAnchor.spanIndex + theAnchor.spanLength - 1 != location: return
+          default: break
+          }
         }
         result.append(.init(keyArray: theNode.keyArray, value: gram.value))
       }

Packages/vChewing_Megrez/Sources/Megrez/4_SpanUnit.swift

@@ -66,11 +66,13 @@ extension Megrez.Compositor {
   /// - Returns: 一個包含所有與該位置重疊的節點的陣列。
   func fetchOverlappingNodes(at givenLocation: Int) -> [NodeAnchor] {
     var results = [NodeAnchor]()
-    guard !spans.isEmpty, givenLocation < spans.count else { return results }
+    let givenLocation = max(0, min(givenLocation, keys.count - 1))
+    guard !spans.isEmpty else { return results }
 
     // 先獲取該位置的所有單字節點。
     (1 ... max(spans[givenLocation].maxLength, 1)).forEach { theSpanLength in
       guard let node = spans[givenLocation][theSpanLength] else { return }
+      guard !node.keyArray.joined().isEmpty else { return }
       results.append(.init(node: node, spanIndex: givenLocation))
     }
 
@@ -81,6 +83,7 @@ extension Megrez.Compositor {
       guard A <= B else { return }
       (A ... B).forEach { theLength in
         guard let node = spans[theLocation][theLength] else { return }
+        guard !node.keyArray.joined().isEmpty else { return }
         results.append(.init(node: node, spanIndex: theLocation))
       }
     }

Packages/vChewing_Megrez/Tests/MegrezTests/LMDataForTests.swift

@@ -173,6 +173,7 @@ nian2zhong1 年中 -11.373044
 gao1ke1ji4 高科技 -9.842421
 zhe4yang4 這樣 -6.000000 // Non-LibTaBE
 ni3zhe4 你這 -9.000000 // Non-LibTaBE
+ke1ke1 顆顆 -8.000000 // Non-LibTaBE
 jiao4 教 -3.676169
 jiao4 較 -3.24869962
 jiao4yu4 教育 -3.32220565

Packages/vChewing_Megrez/Tests/MegrezTests/MegrezTests.swift

@@ -559,4 +559,25 @@ final class MegrezTests: XCTestCase {
     let resultB = compositorB.walk().walkedNodes
     XCTAssertEqual(resultA, resultB)
   }
+
+  func test22_Compositor_SanitizingNodeCrossing() throws {
+    let theLM = SimpleLM(input: strSampleData)
+    let rawReadings = "ke1 ke1"
+    var compositor = Megrez.Compositor(with: theLM)
+    rawReadings.split(separator: " ").forEach { key in
+      compositor.insertKey(key.description)
+    }
+    var a = compositor.fetchCandidates(at: 1, filter: .beginAt).map(\.keyArray.count).max() ?? 0
+    var b = compositor.fetchCandidates(at: 1, filter: .endAt).map(\.keyArray.count).max() ?? 0
+    var c = compositor.fetchCandidates(at: 0, filter: .beginAt).map(\.keyArray.count).max() ?? 0
+    var d = compositor.fetchCandidates(at: 2, filter: .endAt).map(\.keyArray.count).max() ?? 0
+    XCTAssertEqual("\(a) \(b) \(c) \(d)", "1 1 2 2")
+    compositor.cursor = compositor.length
+    compositor.insertKey("jin1")
+    a = compositor.fetchCandidates(at: 1, filter: .beginAt).map(\.keyArray.count).max() ?? 0
+    b = compositor.fetchCandidates(at: 1, filter: .endAt).map(\.keyArray.count).max() ?? 0
+    c = compositor.fetchCandidates(at: 0, filter: .beginAt).map(\.keyArray.count).max() ?? 0
+    d = compositor.fetchCandidates(at: 2, filter: .endAt).map(\.keyArray.count).max() ?? 0
+    XCTAssertEqual("\(a) \(b) \(c) \(d)", "1 1 2 2")
+  }
 }