Hi, arrow. This is very cool and would be super useful. A few of us are working on modding Sublime Text 2 for similar purposes. I do not think that anyone has yet worked up autocomplete for AppGameKit functions, but it would be fairly easy to do in Sublime Text.
Sublime Text has the ability to look at "snippet" files which allows you to link any typed text to the autocomplete feature and fill in whatever you want.
For example:
<snippet>
<content><![CDATA[WriteDebug(debugOn , "" , 0 , 1)]]></content>
<!-- Optional: Tab trigger to activate the snippet -->
<tabTrigger>WriteDebug</tabTrigger>
<!-- Optional: Scope the tab trigger will be active in -->
<scope>source.agk</scope>
<!-- Optional: Description to show in the menu -->
<description>WriteDebug(iOnOff , $sText , iToggleTimeStamp=1or2 , iAppend)</description>
</snippet>
As soon as I begin to type "WriteDebug" the autocomplete comes up and shows me the description "WriteDebug(iOnOff , $sText , iToggleTimeStamp , iAppend)" and if I select that autocomplete then it fills in what I've put in the <content> tags.
I love this feature a LOT. I only wish that there were a way to separate snippets and regular autocompletion better. I suppose I could do something like add an "@" in front of any snippet trigger.
Anyway, the point is that I really think that Sublime text is better as an IDE than notepad++. I think that writing a program that parses the function list that Hodgey has made into snippet files like the above would be AWESOME. Of course if it is an AppGameKit function then it would likely be better to have the data that is filled in be the actual parameter names instead of something like I've used above.
If you're interested in doing this, I think a few of use would be very grateful. Also I think Sublime text is much more suited for this than N++ is (though I love N++ too).
Here's the thread link to the WIP for Sublime Text to AGK:
http://forum.thegamecreators.com/?m=forum_view&t=206696&b=48
EDIT: I forgot to mention. One excellent feature that Sublime Text has and N++ doesn't is multiple selection. So if I have 10 lines I want to simultaneously edit I can quickly and easily do so.