LibStub

LibStub is a minimalistic versioning library that allows other libraries to easily register themselves and upgrade. It is meant to be a cross-community library sharing system.

LibStub is hereby placed in the Public Domain

Credits: Kaelten, Cladhaire, ckknight, Mikk, Ammo, Nevcairiel, joshborke

Returns
An iterator over the registered major libraries.

Who uses LibStub?

 * Ace3, for which it was originally designed


 * Rock, ckknight's framework


 * Auctioneer uses it for its libraries


 * Some Dongle-related libraries use it.


 * ... and hopefully many more to come!

Library

 * get a copy of the current version


 * copy LibStub.lua into your library's folder


 * set up your &lt;library&gt;.toc file to load LibStub.lua (in case you support stand alone loading of the lib)


 * don't load LibStub via the xml file ment for embedded loading of your lib


 * don't set LibStub as X-embeded or OptDep

AddOn

 * set up an external pointing to svn://svn.wowace.com/wow/libstub/mainline/tags/1.0

or


 * get a copy of the current version


 * copy LibStub.lua into your addon's folder or a subfolder of it


 * set up your &lt;addon&gt;.toc or embeds.xml file to load LibStub.lua


 * don't set LibStub as X-embeded or OptDep

Basic example
local lib = LibStub:NewLibrary("MyLibrary-1.0", 1) if not lib then return—already loaded and no upgrade necessary end lib.somearray = lib.somearray or {} if not lib.frame then lib.frame=CreateFrame("Frame") end function lib:SomeFunction -- do stuff here end function lib:SomeOtherFunction -- do other stuff here end local function OnUpdate -- timing stuff here end lib.frame:SetScript("OnUpdate", OnUpdate);

Using revision control system tags for minor version
local lib = LibStub:NewLibrary("MyLibrary-1.0", "$Revision: 12345$")

Do be aware that moving a library from one repository to another will change revision numbers. Do not ever let it slide backwards. If you are caught in this situation, you might want to use something like:

local lib = LibStub:NewLibrary("MyLibrary-1.0",   12345+tonumber(strmatch("%d+","$Revision: 2$"))  )

Embedding / Mixing in
This is a convention rather than a function of the specification, but all Ace3 and Rock related libraries use the following semantics for doing embedding / mixing in (specifically, libraries with an .Embed member can be specified as embeds during addon object creation rather than having to embed them explicitly):

lib.mixinTargets = lib.mixinTargets or {} local mixins = {"SomeFunction", "SomeOtherFunction" } function lib:Embed(target) for _,name in pairs(mixins) do    target[name] = lib[name] end lib.mixinTargets[target] = true end

... and at the end of the file, we handle library upgrades by simply re-embedding the library in all positions where it has previously been embedded / mixed in:

for target,_ in pairs(mixinTargets) do  lib:Embed(target) end