lua module环境探秘

module (name [, ···])

Creates a module. If there is a table in

package.loaded[name]

, this table is the module. Otherwise, if there is a global table

t

with the given 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,

t._M

with the module (

t

itself), and

t._PACKAGE

with the package name (the full module name minus last component; see below). 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

.

2.4.1 – Chunks The unit of execution of Lua is called a chunk. A chunk is simply a sequence of statements, which are executed sequentially. Each statement can be optionally followed by a semicolon:

chunk ::= {stat [`;´]}

There are no empty statements and thus '

;;

' is not legal.
Lua handles a chunk as the body of an anonymous function with a variable number of arguments (see §2.5.9). As such, chunks can define local variables, receive arguments, and return values.

local strkey = "vartwo"

-- 本模块环境
local env = getfenv(1)

env[strkey] = 2

-- 调用此模块的环境
local env_caller = getfenv(2)

env["env_caller"] = env_caller

module(..., package.seeall)

varone = 1

local strkey = "vartwo"

-- 本模块环境
local env = getfenv(1)

env[strkey] = 2

print("vartwo="..vartwo)

-- 调用此模块的环境
local env_caller = getfenv(2)

env["env_caller"] = env_caller

local testmodule = require("module_test")

var_caller = 55

print("testmodule.vartwo=" .. testmodule.vartwo)

local function printTable(tbl)

for k,v in pairs(tbl) do
print("kay="..tostring(k) .. " value="..tostring(v))
end

end

print("----------- testmodule ------------------")

printTable(testmodule)

print("----------- testmodule.env_caller ------------------")

printTable(testmodule.env_caller)

>lua -e "io.stdout:setvbuf 'no'" "main.lua"
vartwo=2
testmodule.vartwo=2
----------- testmodule ------------------
kay=_NAME value=module_test
kay=_PACKAGE value=
kay=varone value=1
kay=_M value=table: 005F9410
kay=vartwo value=2
kay=env_caller value=table: 005F2650
----------- testmodule.env_caller ------------------
kay=string value=table: 005F9398
kay=xpcall value=function: 005F6CE8
kay=module_test value=table: 005F9410
kay=package value=table: 005F7160
kay=tostring value=function: 005F6CC8
kay=print value=function: 005F6808
kay=os value=table: 005F95A0
kay=unpack value=function: 005F6AE8
kay=require value=function: 005F8078
kay=getfenv value=function: 005F6788
kay=setmetatable value=function: 005F6C48
kay=next value=function: 005F66E8
kay=assert value=function: 005F68A8
kay=tonumber value=function: 005F6CA8
kay=io value=table: 005F94D8
kay=rawequal value=function: 005F6828
kay=collectgarbage value=function: 005F6668
kay=arg value=table: 005F92D0
kay=getmetatable value=function: 005F6688
kay=module value=function: 005F7FD8
kay=rawset value=function: 005F6A28
kay=var_caller value=55
kay=math value=table: 005F9348
kay=debug value=table: 005F90F0
kay=pcall value=function: 005F6988
kay=table value=table: 005F72C8
kay=newproxy value=function: 005F0568
kay=type value=function: 005F6D08
kay=coroutine value=table: 005F70C0
kay=_G value=table: 005F2650
kay=select value=function: 005F6708
kay=gcinfo value=function: 005F69E8
kay=pairs value=function: 005F0538
kay=rawget value=function: 005F6908
kay=loadstring value=function: 005F67C8
kay=ipairs value=function: 005F2BD0
kay=_VERSION value=Lua 5.1
kay=dofile value=function: 005F67A8
kay=setfenv value=function: 005F6A08
kay=load value=function: 005F6888
kay=error value=function: 005F6768
kay=loadfile value=function: 005F6848
>Exit code: 0