From be7a5674e61484e7402a40a5d53d5d4983137758 Mon Sep 17 00:00:00 2001
From: ShikiSuen <shikisuen@outlook.com>
Date: Thu, 23 Jun 2022 00:18:42 +0800
Subject: [PATCH] UOM // Deduplication on observing keys.

---
 Source/Modules/LangModelRelated/SubLMs/lmUserOverride.swift | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Source/Modules/LangModelRelated/SubLMs/lmUserOverride.swift b/Source/Modules/LangModelRelated/SubLMs/lmUserOverride.swift
index 17cf6bdb..0bcdc457 100644
--- a/Source/Modules/LangModelRelated/SubLMs/lmUserOverride.swift
+++ b/Source/Modules/LangModelRelated/SubLMs/lmUserOverride.swift
@@ -53,6 +53,9 @@ extension vChewing {
         var observation: Observation = .init()
         observation.update(candidate: candidate, timestamp: timestamp)
         let koPair = KeyObservationPair(key: key, observation: observation)
+        // 先移除 key 再設定 key 的話，就可以影響這個 key 在辭典內的順位。
+        // Swift 原生的辭典是沒有數字索引排序的，但資料的插入順序卻有保存著。
+        mutLRUMap.removeValue(forKey: key)
         mutLRUMap[key] = koPair
         mutLRUList.insert(koPair, at: 0)