LibStub

AddOn article
This page describes fan-made scripting using the World of Warcraft API which has had notable impact on the game's development/history.

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

LibStub-1.0 API

:GetLibrary(major [, silent])

Arguments

Arg	Type	Details
major	string	The name of the library you are requesting
silent	boolean	(Optional) Suppresses errors when the library is not found

Returns

Return	Type	Details
major	table or nil	The table instance of a registered library or nil if not found
minor	number	The minor revision of the registered library

:IterateLibraries()

Returns

An iterator over the registered major libraries.

:NewLibrary(major , minor)

Arguments

Arg	Type	Details
major	string	The name of the library you are requesting
minor	string or number	The minor for the registering library

Returns

Return	Type	Details
major	table or nil	The table to be used by the library.
oldminor	number	The minor revision of the previously registered library

Who uses LibStub?

• Ace3, for which it was originally designed

WoWAce.com Ace3

• Rock, ckknight's framework

WoWAce.com Rock

• Auctioneer uses it for its libraries

• Some Dongle-related libraries use it.

• ... and hopefully many more to come!

How to include LibStub in a library or addon

Library

• get a copy of the current version

• copy LibStub.lua into your library's folder

• set up your <library>.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 <addon>.toc or embeds.xml file to load LibStub.lua

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

Examples

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

External links

svn.WoWAce.com LibStub-1.0

www.WoWAce.com LibStub on wowace.com