AddMessage and other functions?

[WinHack]

I have looked into a few different simple mods and many of them have used the following code:

DEFAULT_CHAT_FRAME:AddMessage(string, number, number, number)

So I basically understand what it does (sends a message to whatever frame it is attached to (in this case, DEFAULT_CHAT_FRAME). I looked into the FrameXML/ChatFrame.Lua file but I could not find the original definition of AddMessage anywhere. I could see that several lines of code within ChatFrame.Lua themselves use AddMessage, however. So the question is: where is AddMessage defined? If I wanted to look up the purpose/range/values for those three numbers, where is that documented?

I looked at the WoWWiki entries but could not find this AddMessage function/command. Doesn't mean it isn't there, mind you, just that I didn't see it. I have a feeling that there are probably more than a handful of useful functions/methods defined at this level that would be nice to know about.

[Gello]

If you don't see a function in the API, check the widgets section also: http://www.wowwiki.com/Widget_API

AddMessage is a widget (I think "method" is technical term) for MessageFrames.

Documentation here: http://www.wowwiki.com/API_MessageFrame_AddMessage

[WinHack]

Thank you very much. I see it now. Will take me a bit to adjust to the way things are distributed here, but I'll get it. Thank you.