This seems like such a simple idea to implement, but I have not found a decent version anywhere.
My idea is to be able to filter which loot to auto-pickup. For instance, if you are trying to farm runecloth from a dungeon then you could set the addon to only pick up runecloth and ignore all other drops.
My idea is this;
You would create a list of items. You would then be able to set whether you want to pick up ONLY things on that list or everything BUT whats on the list. (of course you would want it to always pick up money)
This simple functionality would be invaluable for farming mats. There was an addon called lootfilter and another one called autolootfilter, but both seem to have been abandoned before they could really work properly. Maybe that code could be a starting ground for this new addon.
I have just uploaded an addon (waiting for authorisation) that doesn't do exactly what you want :) BUT, what it does is loot everything that isnt grey - you still get what you didnt want, but less of it! Its called LootMe - development is open to suggestions :)
Blizzard originally didn't pass "self" to any functions, but used a global variable "this" that was set to refer to the same object. Most (all?) Blizzard functions have since been revised to pass "self", but the global "this" is still available, for now at least.
Essentially the old event handlers were function(this, event, arg1, arg2, ..., arg9)... but those params were globals, not passed into the function and therefore locals. It had a few nasty/handy side effects... it was slower and one could modify the global values, thus effecting the way the default UI processed the event.
If the function only receives event and arg1, then arg6 is just nil. But, the same function can receive up to 9 arguments beyond event, and there is some overhead associated with using ..., especially if you're expecting all 9 args to be present.