Today I was busing coding/programming in a bar/pub, had my headphones in (as I always do), trying to concentrate on my work. Around 2 PM an obviously-drunk man walks in and orders a beer, then starts playing darts. Unfortunately for me, I'm sitting right next to the darts station.
The guy starts asking me about me laptop - "oh cool laptop, is that Windows 7, 8, 10?", to which I politely respond, "actually none of those, it's a Macbook, an Apple product so it doesn't use Windows." I was hoping the conversation would stop there. Alas, the guy asks me what Apple is, then starts a conversation about phones and asking me if I know a way to get free (by this he means permanent, and illegal) wifi on his phone.
Needless to say, I didn't want to have this conversation, but I politely diffused by saying "oh I'm so sorry but I'm not from around here and I don't know how phones and connections work here." At this point I should mention that I'm American and living in northern France, where random drunken people trying to start a conversation with me (read: a total stranger) is far more common than any other part of the world I've been in.
Long story short, how can I - without offending the person who is drunk - diffuse the conversation into something like ""I'm sorry, but I'm busy (and not interested in talking to you right now)"?
Primarily I'm asking how to diffuse drunk French people, but this has also happened a lot to me in the U.S. so I'd like a general solution, not culture-specific.
PS - obviously I know I could choose a more suitable work environment, but I'm sorry, I like the atmosphere of bars and the ability to get some of my favorite beers on tap. I just want to avoid drunk people trying to strike up a conversation with me; it should be noted that as I mentioned, headphones don't seem to a deterrent.