lua decorator，类似python那样的装饰器

decorator

local function decorator(str)
	local rebuild_str = {}
	local rebuild_fun = "(\0)"
	local state = 0
	for line in str:gmatch('[^\r\n]+') do
		if line:find("@") then
			rebuild_fun = string.format("(%s"..rebuild_fun..")", line:sub(2))
			state = 1
		else
			if state==0 or state==3 then
				table.insert(rebuild_str, line)
				table.insert(rebuild_str, "\n")
			elseif state==1 then
				if line:find("function") then
					local func = line:match("function%s(.*)")
					local name, args = func:match("(%S+)%((.*)%)")
					local newname = name .."__________decorator"
					
					rebuild_fun = rebuild_fun:gsub("\0", newname..", "..args)
					rebuild_fun = line.."\n\treturn " .. rebuild_fun .. "\nend"
					
					table.insert(rebuild_str, (line:gsub(name, newname)))
					table.insert(rebuild_str, "\n")
					state = 2
				else
					assert(false, "after decorator need function")
				end
			elseif state==2 then
				table.insert(rebuild_str, line)
				table.insert(rebuild_str, "\n")
				if line:find("end") then
					state = 3
				end
			end
		end
	end
	assert(state==3, "decorator error")
	table.insert(rebuild_str, rebuild_fun)
	
	local chunk = table.concat(rebuild_str)
	local f, err = load(chunk)
	assert(f, err)
	f()
end

decorator[[
local function check_in(...)
	local types = {...}
	return function(f, ...)
		local args = {...}
		assert(#types==#args, "check_in args error")
		for i,v in ipairs(args) do
			assert(type(v)==types[i], "check_in args error")
		end
		return f, ...
	end
end

local function check_out(...)
	local types = {...}
	return function(f, ...)
		local function get_ret(...)
			return {...}
		end
		local args = get_ret(f(...))
		assert(#types==#args, "check_out args error")
		for i,v in ipairs(args) do
			assert(type(v)==types[i], "check_out args error")
		end
		return table.unpack(args)
	end
end

@check_in("number", "number")
@check_out("boolean")
function test(a, b)
	return true
end
]]

print( test(1, 2) )