Lua编程示例（二）：面向对象、metatable对表进行扩展_Lua

Lua编程示例（二）：面向对象、metatable对表进行扩展

2020-05-06 10:30脚本之家 Lua

这篇文章主要介绍了Lua编程示例（二）：面向对象、metatable对表进行扩展,本文直接给出实例代码,需要的朋友可以参考下

				?

									counter = {

									 count = 0

									}

									function counter.get(self)

									 return self.count

									end

									function counter:inc()

									 self.count=self.count+1

									end

									print(counter.get(counter))

									counter.inc(counter)

									print(counter.get(counter))

									counter2={

									 count=4,

									 get = counter.get,

									 inc = counter.inc,

									}

									print(counter2:get())

									counter.inc(counter2)

									print(counter2.get(counter2))

									print()

									tb1 ={ "alpha","beta","gamma"}

									mt={}

									setmetatable(tb1,mt)

									print(getmetatable(tb1) == mt)

									print()

									function mt.__add(a,b)

									 local result = setmetatable({},mt)

									 for i=1,#a do

									 table.insert(result,a[i])

									 end

									 for i=1,#b do

									 table.insert(result,b[i])

									 end

									 return result

									end

									tb2={"aaa","bbb","ccc"}

									res=tb1+tb2

									for i,v in ipairs(res) do

									 print(v)

									end

									print()

									function mt.__unm(a)

									 local result = setmetatable({},mt)

									 for i=#a , 1 ,-1 do

									 table.insert(result,a[i])

									 end

									 return result

									end

									res=-tb1+tb2

									for i,v in ipairs(res) do

									 print(v)

									end

									print()

									function mt.__tostring(a)

									 local result = "{"

									 for i,v in ipairs(a) do

									 result = result.." "..v

									 end

									 result = result.." } "

									 return result

									end

									print(tb1)

									function mt.__index(tb1,key)

									 print("there is no "..key.." in the table")

									 return nil

									end

									print(tb1["fsy"])

									function mt.__newindex(a,key,v)

									 if( key == "haha") then

									 error(" Stop laugh!",2)

									 else

									 rawset(a,key,v)

									 end

									end

									tb1.haha="heihei"

运行结果：

				?

									0

									1

									4

									5

									true

									alpha

									beta

									gamma

									aaa

									bbb

									ccc

									gamma

									beta

									alpha

									aaa

									bbb

									ccc

									{ alpha beta gamma } 

									there is no fsy in the table

									nil

									lua: my_test.lua:166: Stop laugh!

									stack traceback:

									 [C]: in function 'error'

									 my_test.lua:160: in function <my_test.lua:158>

									 my_test.lua:166: in main chunk

									 [C]: ?