lua5.2文档

模块管理：
The package library provides basic facilities for loading modules in Lua. It exports one function directly in the global environment: require. Everything else is exported in a table package.

require (modname)
require returns the value stored at package.loaded[modname]. Otherwise, it tries to find a loader for the module.


module (name [, ···])
Creates a module. If there is a table in package.loaded[name], this table is the module.Otherwise creates a new table t and sets it as the value of the global name and the value of package.loaded[name].
This function also initializes t._NAME with the given name,

Finally, module sets t as the new environment of the current function and the new value of package.loaded[name], so that require returns t.

package.seeall (module)
Sets a metatable for module with its __index field referring to the global environment, so that this module inherits values from the global environment. To be used as an option to function module.

摘自：http://blog.163.com/hbu_lijian/blog/static/126129153201422902256778/
1.dofile与loadfile
dofile当作Lua运行代码的chunk的一种原始的操作。dofile实际上是一个辅助的函数。真正完成功能的函数是loadfile；与dofile不同的是loadfile编译代码成中间码并且返回编译后的chunk作为一个函数，而不执行代码；另外loadfile不会抛出错误信息而是返回错误代。我们可以这样定义dofile：
function dofile (filename)
    local f = assert(loadfile(filename))
    return f()
end

如果loadfile失败assert会抛出错误。loadfile更加灵活。在发生错误的情况下，loadfile返回nil和错误信息，这样我们就可以自定义错误处理。另外，如果我们运行一个文件多次的话，loadfile只需要编译一次，但可多次运行。dofile却每次都要编译。

loadstring (string [, chunkname])
Similar to load, but gets the chunk from the given string.
To load and run a given string, use the idiom
     assert(loadstring(s))()
When absent, chunkname defaults to the given string.


Lua5.2：部分变化：
Function module is deprecated. It is easy to set up a module with regular Lua code.
Functions setfenv and getfenv were removed, because of the changes in environments.
增加 bit32模块