> My recollection is that part of the indexing interface in Julia (just by > convention) is that indexing should be of O(1) (or close to that) > complexity.
As the OP suggested, this could still be the case, the zip object would simply forward the indexing to the zipped collections, which would fail if one of then is not indexable (in O(1)). Alternatively there could be a trait for that. I've also wanted that for a long time, and even setindex!, to be able to sort an array2 according to the order defined in array1: sort!(zip(array1, array2)).
