pack和unpack

对于一个函数，要将其入参转换为一个表，则pack函数合适。

对于一个表要将其转换为一个函数的入参，则 lua原生提供的 unpack函数可以实现。

do

arrayData = {"a", "b", "c", "d", "e"};

function pack(...)

return {...};

end

print( pack("aa", "bb")[2] );

--print((returnMoreValues()));

--print(arrayData); -- print the address of the arrayData

--print(unpack(arrayData)); -- print all the elements of the arrayData

print(unpack(arrayData, 2)); --the second param is the index of the arrayData

end

>lua -e "io.stdout:setvbuf 'no'" "luatest.lua"

b c d e

>Exit code: 0

>lua -e "io.stdout:setvbuf 'no'" "luatest.lua"

aa

b c d e

>Exit code: 0

>lua -e "io.stdout:setvbuf 'no'" "luatest.lua"

bb

b c d e

>Exit code: 0

lua脚本函数也可以序列化

函数序列化，可以实现函数的跨进程功能。如果此函数是动态的产生的，并且需要跨进程访问。

序列化加密
string.dump(loadstring(ret))
这就是加密的代码，因为string.dump参数必须是function, 所以使用loadstring将字符串加载成chunk,然后在由string.dump导成字节码
其实就是使用了string.dump函数，它可以把function导成二进制字节码，使用它处理一下就可以把明文字符串转成字节码了

local function ser(var, enc)

assert(type(var)=="table")

-- 标记所有出现的table, 并记录其key, 用于处理循环引用

local mark = {}

-- 用于记录循环引用的赋值语句

local assign = {}

-- 序列化表, ret字符串必须与后面的loca ret=%s中的ret相同，因为这个ret可能也会组织到结果字符串中。

local ret = table_ser(var, "ret", mark, assign)

local ret = string.format("local ret=%s %s return ret", ret, table.concat(assign, ";"))

return (enc==nil or enc==true) and string.dump(loadstring(ret)) or ret

end

接口可以多次调用给指定的模块添加新接口

void luaL_register (lua_State *L,                    const char *libname,                    const luaL_Reg *l);
Opens a library.

When called with libname equal to NULL, it simply registers all functions in the list l (see ) into the table on the top of the stack.

When called with a non-null libname, luaL_register creates a new table t, sets it as the value of the global variable libname, sets it as the value of package.loaded[libname], and registers on it all functions in the list l. If there is a table in package.loaded[libname] or in variable libname, reuses this table instead of creating a new one.

In any case the function leaves the table on the top of the stack.