Lua编程示例（二）：面向对象、metatable对表进行扩展（lua面向对象是怎么实现的）学到了


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= ”
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”