Why isn't it "Vi har en rast nu"? Is it just similar to how you don't use an article when talking about professions?
Yes, sort of. It isn't wrong to say Vi har en rast nu but there's a tiny difference in meaning and the one without an article is the most useful version of the sentence. Adding en makes it a little more about having an individual break while ha rast is more like an activity, almost as if it were a verb in its own right. The stress is on rast too, just like in particle verbs.
You could use it when saying that you're (only) having one break, as opposed to more than one.
Since 'vi har rast nu' is 'we are having a break now' would 'vi tar rast nu' mean 'we are taking a break now'?.....( that was my first answer).
I think "taking a break" would be acceptable, as well as "having a break". Of course, it's not as literal, but at least in American English and idiomatically, it should work. Discuss.
You can both ta 'take' and ha 'have' breaks in Swedish too and the difference is pretty much the same as in English.
In English you can have a rest or take a break, you cannot have a break or take a rest.
Saying "we are having a break now" would cost you points for grammar in English class in middle school.
It's cultural. Under the Anglo-Saxon economic model breaks are still not something everyone is granted, nevermind entitled to. You don't always just get to have breaks, you have to take them.
I'm not sure I agree that they are different; in British English it is quite common to say that one is "having/taking a rest" to indicate taking a break from one's labours. Or perhaps I'm not understanding the implied meaning of the phrase given here.
I think I agree with you both. Having a rest is more ambiguous in meaning, so perhaps it's better that it's not accepted. Unless of course rast is only ever used in reference to a scheduled break. In other situations I'd say that having a break is synonymous with having a rest.
Yes, en rast is short. It cannot last for weeks (although that sounds like a nice idea). We'd call that ett lov if you're free from school. Normally in compound form like jullov (at Christmas), sommarlov (in the summer), or påsklov (at Easter).