Wiley-World.of.Warcraft.Programming.A.Guide.and.Reference.for.Creating.WoW.Addons

Chapter 25 ■ Taking Protected Action in Combat 489with “_on“; that is, if triggered by a change to the state-unitexists attribute,it looks for a snippet to handle that attribute in the _onstate-unitexistsattribute. Instead of the raw name and value arguments, it calls that snippetwith the stateid argument, which is the name of the changed attribute minusthe “state-“ portion, and the newstate argument, which is the same as value.That is, if the state handler was triggered by a change in the state-unitexistsattribute, the stateid argument will be “unitexists“.To see one rather remarkable way you can use SecureHandlerStateTemplate, enter the following block into a fresh page in-game (if you don’thave a priest to test this with, substitute spells or items appropriate to yourcharacter):local self = AvatarCaster or CreateFrame(“Button“, “AvatarCaster“, inil, “SecureActionButtonTemplate,SecureHandlerStateTemplate“)self:Hide()self:SetAttribute(“_onstate-mouseover“, [[if newstate == “exists“ thenlocal name = self:GetName()self:SetBindingClick(false, “SHIFT-BUTTON1“, name, “shift1“)self:SetBindingClick(false, “CTRL-BUTTON1“, name, “ctrl1“)self:SetBindingClick(false, “SHIFT-BUTTON2“, name, “shift2“)self:SetBindingClick(false, “CTRL-BUTTON2“, name, “ctrl2“)elseself:ClearBindings()end ]])RegisterStateDriver(self, “mouseover“, i“[target=mouseover,exists] exists; noexists“)self:SetAttribute(“unit“, “mouseover“)self:SetAttribute(“type“, “spell“)self:SetAttribute(“*spell-shift1“, “Power Word: Fortitude“)self:SetAttribute(“*spell-shift2“, “Power Word: Shield“)self:SetAttribute(“*spell-ctrl1“, “Flash Heal“)self:SetAttribute(“*spell-ctrl2“, “Renew“)Run this script once you’ve finished it. Try holding down Shift or Controland clicking various character or monster avatars in the game-world display;observe how spells are cast on them directly without changing your target.Now, you can break down how it works.The frame is created from a combination of SecureActionButtonTemplate(so that it can actually cast spells) and SecureHandlerStateTemplate (so thatit can respond to changes in the game state). The AvatarCaster or portionsimply prevents you from creating a new frame if you need to run the scriptmore than once, such as by making an error in the script the first time. The