Combine RACTuple with RACSequence

[jspahrsummers]

If RACSequence supported indexing and had first, second, etc. convenience methods like RACTuple, we could effectively get rid of the latter and be left with much more flexible tuples.

[joshaber]

RACTuple's main use is holding nil in a collection.

[jspahrsummers]

Hmm, that is a problem, but I don't like how terrible tuples are to work with right now.

Maybe RACTuple could be a special RACSequence subclass which maps to and from RACTupleNil as appropriate, similarly to how it uses NSArray internally right now?

[joshaber]

Yep, that'd work.

[Coneko]

Depends on whether you want a tuple class at all really.

I find it a bit strange that +combineLatest: takes an NSArray as a parameter, but then returns a RACTuple.
The fact that in +combineLatest:reduce: the reduceBlock is given parameters separately instead of wrapped in a RACTuple seems to imply tuples are the expected way of handling the combined subscribables, but the fact that RACTuple is a collection object that can be iterated on doesn't really confirm that.

If RACTuple's aim is only to simplify handling nil in collections, which by itself is already a very handy thing, then a special sequence instead of a different class seems to be better. A method could be added to RACSequence (or to RACStream even) to convert any sequence to it's equivalent automatically-converting nil version.

If instead RACTuple is supposed to be a tuple, I think having a tuple sequence is very confusing.

[joshaber]

I'm not sure the added conceptual weight of RACTuple is worth it. Tuples don't really give us anything sequences couldn't. The semantic difference is nice but pretty foreign in Cocoa and without any real payoff.

[Coneko]

On second thought, from what I can see RACTuple is pretty much an internal class born from the necessity of having RACSignal distinguish between nil and +[NSNull null] since both are valid values.

I don't think it's going to be useful to combine it with RACSequence given it's purpose.

[joshaber]

Now that RACTupleUnpack exists it has a more useful role as a true tuple.