Lua 栈的简单实现

local Stack = {}

function Stack:new()
	local t = {}
	setmetatable(t, self)
	self.__index = self
	return t
end

function Stack:push(data)
	self[#self+1] = data
end

function Stack:pop()
	local data = self:top()
	if not data then
		return nil
	end
	table.remove(self,#self)
	return data
end

function Stack:top()
	local data = self[#self]
	if not data then
		return nil
	end
	return data
end