[swift-evolution] Adding Result to the Standard Library

[Jon Shier]

> I would argue that a successful addition to the standard library *must* have such additional justification about why it needs built-in support. If it's already in use as a third-party library, and you're arguing that the third-party design is already quite satisfactory and there's no built-in support required, then that's fundamentally an argument that it *doesn't* need to be in the standard library.

	What? That doesn’t make any sense at all. I’ve written this proposal to get a very popular and useful type into the standard library exactly because it’s so popular and useful. It’s so popular and useful, in fact, that users are running into issues getting all of the third-party implementations to play well together. I’ll be adding more to the proposal about the general usefulness of the Result type tomorrow, but it has often been said on this mailing list that one of the ways a type can become part of the standard library is by becoming popular in the community. My assertion is that Result has reached that point and so needs consideration for the benefit of not only all current users of the type, but the community in general. 
	I could also be confused about what you mean about “built-in” support, or the types of things you’d think a standard library Result type should do that isn’t in the proposal. In that case, could you be much more specific about what additions you think it needs?



Jon