How can you use “either… or” twice in a sentence?

Question

I want to be able to say something like:

There either needs to be X to do either X_a or X_b or there needs to be Y.

(edit: since from some answers it doesn't seen to be clear, I mean that that X_a and X_b would only happen under X, not Y. )

Is there any way I can make it less cumbersome or more clear which "either" the "or"s are associated with?

edit2

I think the word "do" is confusing things. Another way of phrasing it would be:

There either needs to be X which would either [have behaviour] X_a or [behaviour] X_b or there needs to be Y.

Answer 1

If you keep it exactly as it's written, it doesn't need fixing. All the *either*s and *or*s are close together, so it's easy to analyse the sentence at a single glance. (I'd prefer to put the either between be and X, but that doesn't change the meaning.) But if the Xs and Ys get longer, it could be hard to read. So your options are:

Option 1: Punctuate

There needs to be either X, to do either Xa or Xb, or Y.

There needs to be either X (to do either Xa or Xb) or Y.

Option 2: Reorder

Nested structures are generally more readable if you put the inner structure at the end of the outer one. So you could reword your sentence like this:

There needs to be either Y, or there needs to be X to do either Xa or Xb.

but, to be honest, it doesn't make a lot of difference.

Option 3: Break it up

There either needs to be X or Y. X would be to do either Xa or Xb.

Option 4: Substitute one of the either ... or structures

... but I can't think of an equivalent structure that doesn't use or and isn't long and unwieldy. I'm sure one of the other answerers will come up with something.

Answer 2

I think the short answer is that as English as no clear way of indicating groupings and sub-groupings in a hierarchical structure, any such sentence has the potential to be confusing. In a computer language we could clearly say, "if condition1 then if condition2 then X1 else X2 endif else Y" or some such. But English isn't so precise. In a specific example it might be clear from context.

For example: "We'll either paint the walls, either blue or green, or we'll tear them down." I think it's pretty clear that tearing them down is not a color of paint, etc, so there's no ambiguity.

But, "We'll either paint the walls or we'll put on wallpaper, either blue or green." Do the colors refer to wallpaper or to both paint and wallpaper? Probably not to just paint or we wouldn't have put it at the end.

Or, "We'll either get someone from accounting to look at this, either Bob or Sally, or maybe we'll ask Joe for help." From the fact that there are two "either"'s, I'd think "ask Joe" is an alternative "get someone from accounting". But the fact that three people are named lures one into thinking that Bob, Sally, and Joe might all be "someone from accounting".

Answer 3

• There needs either to be X to do X_a or X_b, or else there needs to be Y.
• There needs either to be X to do X_a or X_b, or else Y.

A comma helps, and careful phrasing. That way the either can more easily govern and guide the two separate halves of the disjunction. It also seems better to factor out the duplicated there needs to be.

Answer 4

If this is just a question of expressing that idea clearly, I'd say it the other way. This and that produces X or Y.