笔划输入法查找算法示例（Lua实现）

公司同事最近利用谷歌拼音输入法源代码实现了自己的拼音输入法，经过了解，最核心的就是一个trie（词典树）的构造和检索（这里不太介绍trie树了，google一搜一大把），于是今天就想实现了一个笔划输入法。大概的想法是：

1. 找一个所有汉字或者一、二级汉字的笔顺数据库
2. 用Lua将数据库读进来，构造一个trie树
   1. 每一个节点存一个笔划
   2. 每一个节点带一个子节点集合
   3. 每一个节点带一个汉字集合，表示到这一级时所有笔划组成的完整汉字
3. 检索时根据用户输入的笔划，检索到一个节点，然后按笔划顺序遍历子树
   1. 遍历子树可以给出所有以这些笔划开始的所有汉字，但是总不能一下显示出来吧，所以需要一个迭代器，每调用一次给出一个可能的值，这个迭代器用C实 现比较复杂，但是用Lua实现简直就是小意思，直接将遍历子树的函数封装到一个coroutine中，每找到一个汉字就 yield(汉字) 即可

笔顺数据库

CSDN上可以下载到 http://download.csdn.net/detail/yyjlan/3766691

下载的mdb格式，我不太喜欢，Lua也不太喜欢。由于luasql支持odbc，所以可以将mdb文件加入到odbc数据源，然后载入后转成sqlite3的格式，方便以后使用，转换代码如下

 1 require "luasql.odbc"

 2 require "luasql.sqlite3"

 3 

 4 odbc_env = luasql.odbc()

 5 

 6 -- 将Access文件在控制面板->管理工具->数据源 中增加到用户DSN，名称是hzbs

 7 odbc_conn = odbc_env:connect("hzbs")

 8 odbc_cur = odbc_conn:execute("SELECT * FROM hzbs;")

 9 

10 sqlite_env = luasql.sqlite3()

11 sqlite_conn = sqlite_env:connect("hzbs.sqlite3.db")

12 sqlite_conn:execute("CREATE TABLE hzbs (id INTEGER primary key, hanzi TEXT, stroke_number INTEGER, stroke_order TEXT, unicode TEXT, gbk TEXT);")

13 sqlite_conn:setautocommit(false) -- start transaction

14 

15 record = {}

16 while odbc_cur:fetch(record, "n") do

17     local id = record[1]

18     local hanzi = record[2]

19     local stroke_number = record[3]

20     local stroke_order = record[4]

21     local unicode = record[5]

22     local gbk = record[6]

23     sqlite_conn:execute("INSERT INTO hzbs(id, hanzi, stroke_number, stroke_order, unicode, gbk) VALUES(" .. id .. ",\'" .. hanzi .. "\'," .. stroke_number .. ",\'" .. stroke_order .. "\',\'" .. unicode .. "\',\'" .. gbk .. "\');")

24 end

25 

26 sqlite_conn:commit() -- commit the transaction

27 sqlite_conn:close()

28 

29 odbc_cur:close()

30 odbc_conn:close()

31 odbc_env:close()

构造子树与检索

多的不说，直接看代码吧。代码写得有点乱，不过凑合看是没什么问题的。要运行代码必须要先安装 LuaForWindows

  1 require "luasql.sqlite3"

  2 require "wx"

  3 

  4 

  5 function _T(s)

  6     return s

  7 end

  8 

  9 -- enum stroke_t {

 10 local stroke_root = 0 -- for trie root, not a valid stroke

 11 local stroke_heng = 1

 12 local stroke_shu = 2

 13 local stroke_pie = 3

 14 local stroke_na = 4

 15 local stroke_zhe = 5

 16 local stroke_max = 5

 17 local stroke_text = {_T"一", _T"丨", _T"丿", _T"丶", _T"乛"}

 18 -- }

 19 

 20 function new_node(stroke)

 21     return {stroke=stroke,  -- see stroke definition

 22         subnodes = {},  -- next strokes

 23         hanzis={} -- two or more hanzi could have the same stroke order

 24     }

 25 end

 26 

 27 function new_trie()

 28     return new_node(stroke_root)

 29 end

 30 

 31 -- insert hanzi and create the trie

 32 function insert_hanzi(node, stroke_order, hanzi)

 33     local stroke, not_found_index

 34     for i = 1, #stroke_order do

 35         stroke = tonumber(stroke_order:sub(i,i))

 36         if node.subnodes[stroke] then

 37             node = node.subnodes[stroke]

 38         else

 39             not_found_index = i

 40             break

 41         end

 42     end

 43     if not_found_index then

 44         for i = not_found_index, #stroke_order do

 45             stroke = tonumber(stroke_order:sub(i,i))

 46             node.subnodes[stroke] = new_node(stroke)

 47             node = node.subnodes[stroke]

 48         end

 49     end

 50     table.insert(node.hanzis, hanzi)

 51 end

 52 

 53 -- 看看strokes数组组成的笔划顺序的节点是否存在，如果存在则返回节点

 54 function find_node(root, strokes)

 55     local node = root

 56 

 57     if #strokes < 1 then

 58         return nil

 59     end

 60 

 61     for i, stroke in ipairs(strokes) do

 62         if node.subnodes[stroke] then

 63             node = node.subnodes[stroke]

 64         else

 65             return nil

 66         end

 67     end

 68     return node

 69 end

 70 

 71 function db_to_trie(db_name)

 72     local env = luasql.sqlite3()

 73     local conn = env:connect(db_name)

 74     local cur = conn:execute("SELECT hanzi,stroke_order FROM hzbs;")

 75     local trie = new_trie()

 76 

 77     record = {}

 78     while cur:fetch(record, "a") do

 79         insert_hanzi(trie, record.stroke_order, record.hanzi)

 80     end

 81 

 82     cur:close()

 83     conn:close()

 84     env:close()

 85 

 86     return trie

 87 end

 88 

 89 function get_hanzi_enumerator(root)

 90     local traverse

 91 

 92     traverse = function(node)

 93         for i = 1, #node.hanzis do

 94             coroutine.yield(node.hanzis[i])

 95         end

 96 

 97         for stroke = 1, stroke_max do

 98             if node.subnodes[stroke] then

 99                 traverse(node.subnodes[stroke])

100             end

101         end

102     end

103     local co = coroutine.create(function () traverse(root) end)

104 

105     return (function ()

106         local ret, hanzi = coroutine.resume(co)

107         if not ret then -- already stopped

108             return nil

109         elseif hanzi == nil then -- the last call, no yield and no return value

110             return nil

111         else

112             return hanzi

113         end

114     end)

115 end

116 

117 ---------------------------------------------------------------

118 -- GUI

119 local new_id = (function ()

120     local id = wx.wxID_HIGHEST

121     return (function ()

122         id = id + 1

123         return id

124     end)

125 end)()

126 

127 dialog = wx.wxDialog(wx.NULL, new_id(), _T"Lua笔划输入法演示",

128     wx.wxDefaultPosition, wx.wxDefaultSize)

129 panel = wx.wxPanel(dialog, wx.wxID_ANY)

130 local main_sizer = wx.wxBoxSizer(wx.wxVERTICAL)

131 

132 -- 横竖撇捺折 按钮

133 local stroke_label = wx.wxStaticText(panel, new_id(), _T"可选笔划")

134 local heng_button = wx.wxButton(panel, stroke_heng, stroke_text[stroke_heng])

135 local shu_button = wx.wxButton(panel, stroke_shu, stroke_text[stroke_shu])

136 local pie_button = wx.wxButton(panel, stroke_pie, stroke_text[stroke_pie])

137 local na_button = wx.wxButton(panel, stroke_na, stroke_text[stroke_na])

138 local zhe_button = wx.wxButton(panel, stroke_zhe, stroke_text[stroke_zhe])

139 

140 local button_sizer = wx.wxBoxSizer(wx.wxHORIZONTAL)

141 button_sizer:Add(stroke_label, 0, wx.wxALIGN_LEFT+wx.wxALL, 5)

142 button_sizer:Add(heng_button, 0, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

143 button_sizer:Add(shu_button, 0, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

144 button_sizer:Add(pie_button, 0, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

145 button_sizer:Add(na_button, 0, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

146 button_sizer:Add(zhe_button, 0, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

147 

148 main_sizer:Add(button_sizer, 0, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

149 

150 -- 输入笔划列表

151 local input_label = wx.wxStaticText(panel, new_id(), _T"输入笔划")

152 local input_textctrl = wx.wxTextCtrl(panel, new_id(), "",

153     wx.wxDefaultPosition, wx.wxDefaultSize, wx.wxTE_READONLY)

154 local input_backspace_button = wx.wxButton(panel, new_id(), _T"退格")

155 local input_clear_button = wx.wxButton(panel, wx.wxID_CANCEL, _T"清除")

156 

157 local input_sizer = wx.wxBoxSizer(wx.wxHORIZONTAL)

158 input_sizer:Add(input_label, 0, wx.wxALIGN_LEFT+wx.wxALL, 5)

159 input_sizer:Add(input_textctrl, 1, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

160 input_sizer:Add(input_backspace_button, 0, wx.wxALL, 5)

161 input_sizer:Add(input_clear_button, 0, wx.wxALL, 5)

162 main_sizer:Add(input_sizer, 1, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

163 

164 -- 备选汉字

165 local candidate_label = wx.wxStaticText(panel, new_id(), _T"备选汉字")

166 local candidate_sizer = wx.wxBoxSizer(wx.wxHORIZONTAL)

167 candidate_sizer:Add(candidate_label, 0, wx.wxALIGN_LEFT+wx.wxALL, 5)

168 

169 local candidate_number = 5

170 function create_candidate_btn(num)

171     local textctrls = {}

172     for i= 1, num do

173         textctrls[i] = wx.wxButton(panel, new_id(), "")

174         candidate_sizer:Add(textctrls[i], 1, wx.wxALIGN_LEFT+wx.wxALL+wx.wxEXPAND, 5)

175     end

176     textctrls.start_id = textctrls[1]:GetId()

177     textctrls.end_id = textctrls.start_id + candidate_number - 1

178     return textctrls

179 end

180 local candidate_textctrls = create_candidate_btn(candidate_number)

181 main_sizer:Add(candidate_sizer, 1, wx.wxALIGN_LEFT+wx.wxALL+wx.wxEXPAND, 5)

182 

183 -- 选择输出的汉字

184 local output_textctrl = wx.wxTextCtrl(panel, new_id(), "", wx.wxDefaultPosition,

185     wx.wxSize(0, 100), wx.wxTE_MULTILINE)

186 local output_sizer = wx.wxBoxSizer(wx.wxHORIZONTAL)

187 output_sizer:Add(output_textctrl, 1, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 5)

188 main_sizer:Add(output_sizer, 0, wx.wxALIGN_LEFT+wx.wxEXPAND+wx.wxALL, 0)

189 

190 main_sizer:SetSizeHints(dialog)

191 dialog:SetSizer(main_sizer)

192 

193 -- 必须加，否则不能正确退出程序

194 dialog:Connect(wx.wxEVT_CLOSE_WINDOW,

195     function (event)

196         dialog:Destroy()

197         event:Skip()

198     end)

199 

200 -- 读入笔划数据库

201 local trie = db_to_trie("hzbs.sqlite3.db")

202 

203 -- 输入的stroke数组

204 input_strokes = {}

205 get_next_candidate = nil

206 

207 function update_candidate()

208     if get_next_candidate == nil then

209         for _,textctrl in ipairs(candidate_textctrls) do

210             textctrl:SetLabel("")

211         end

212     else

213         for _,textctrl in ipairs(candidate_textctrls) do

214             local hanzi = get_next_candidate()

215             if hanzi then

216                 textctrl:SetLabel(hanzi)

217             else

218                 textctrl:SetLabel("")

219             end

220         end

221     end

222 end

223 

224 function update_input()

225     local text = {}

226     for _,stroke in ipairs(input_strokes) do

227         table.insert(text, stroke_text[stroke])

228     end

229 

230     input_textctrl:SetValue(table.concat(text, " "))

231 end

232 

233 function insert_stroke(stroke)

234     table.insert(input_strokes, stroke);

235     local node = find_node(trie, input_strokes)

236     if node == nil then

237         table.remove(input_strokes) -- 删除不合法的输入

238         -- BEEP

239     else

240         get_next_candidate = get_hanzi_enumerator(node)

241         update_input()

242         update_candidate()

243     end

244 end

245 

246 function remove_stroke()

247     table.remove(input_strokes)

248     local node = find_node(trie, input_strokes)

249     if node == nil then

250         get_next_candidate = nil

251     else

252         get_next_candidate = get_hanzi_enumerator(node)

253     end

254 

255     update_input()

256     update_candidate()

257 end

258 

259 function clear_stroke()

260     input_strokes = {}

261     get_next_candidate = nil

262     update_input()

263     update_candidate()

264 end

265 

266 dialog:Connect(wx.wxID_ANY, wx.wxEVT_COMMAND_BUTTON_CLICKED,

267     function(event)

268         local id = event:GetId()

269         if id <= stroke_max then

270             insert_stroke(id)

271         elseif id >= candidate_textctrls.start_id and id <= candidate_textctrls.end_id then

272             output_textctrl:AppendText(candidate_textctrls[id-candidate_textctrls.start_id+1]:GetLabel())

273             clear_stroke()

274         elseif id == input_backspace_button:GetId() then

275             remove_stroke()

276         elseif id == input_clear_button:GetId() then

277             clear_stroke()

278         end

279     end)

280 

281 dialog:Connect(wx.wxID_ANY, wx.wxEVT_KEY_DOWN, function (event)

282     local key = event:GetKeyCode()

283     local callbacks = {    }

284     callbacks[wx.WXK_NUMPAD7] = function ()

285         insert_stroke(stroke_heng)

286     end

287     callbacks[wx.WXK_NUMPAD8] = function ()

288         insert_stroke(stroke_shu)

289     end

290     callbacks[wx.WXK_NUMPAD9] = function ()

291         insert_stroke(stroke_pie)

292     end

293     callbacks[wx.WXK_NUMPAD4] = function ()

294         insert_stroke(stroke_na)

295     end

296     callbacks[wx.WXK_NUMPAD5] = function ()

297         insert_stroke(stroke_zhe)

298     end

299     callbacks[wx.WXK_BACK] = function ()

300         remove_stroke()

301     end

302     for i = 1, candidate_number do

303         callbacks[i - 1 + string.byte("1")] = function ()

304             output_textctrl:AppendText(candidate_textctrls[i]:GetLabel())

305             clear_stroke()

306         end

307     end

308 

309     if callbacks[key] then

310         callbacks[key]()

311     end

312 end)

313 

314 -- wxwindgets比较特殊，子窗口的按键是发不到主窗口的，需要这样处理下

315 function process_children_keydown_event(parent, processer)

316     local wnd

317     local wlist = parent:GetChildren()

318 

319     for i = 0, wlist:GetCount()-1 do

320         wnd = wlist:Item(i):GetData():DynamicCast("wxWindow")

321         wnd:SetNextHandler(processer)

322         process_children_keydown_event(wnd, processer)

323     end

324 end

325 

326 process_children_keydown_event(dialog, dialog)

327 

328 

329 dialog:Centre()

330 dialog:Show(true)

331 input_textctrl:SetFocus() --放这里没有响声

332 

333 wx.wxGetApp():MainLoop()

 

打包下载

源代码包和sqlite3数据库可以在这里下载