Turn Slack map into struct

[BlakeWilliams]

The "slack" state is currently a map but would be better as a struct so it can be better documented and functions that manipulate/interact with it can be separated from the rest of the code.

[christhekeele]

Was thinking about taking on a couple of these issues. For this one, do you want to turn Slack itself into a struct, or put it somewhere else to avoid cluttering the macro-ful module, like Slack.Conn?

[christhekeele]

Also, how do you feel other structs, like Slack.Message, Slack.User. Slack.Channel, etc?

[BlakeWilliams]

I would move the Slack state first, but it would probably be in its own module. I was initially thinking Slack.State but could be convinced of other names.

I think once that's done it'll make sense to re-evaluate the idea of Slack.Message, user, etc.

[christhekeele]

Both Slack.Struct and Slack.State seem a little nondescript, but I can't think of a great alternative. Slack.API is kind of inaccurate. Slack.Conn and Slack.Client work better, but kind of already occupy a space in the domain model (websocket conn + client).

[christhekeele]

Alternatively, flip it around such that the state is a %Slack{} struct and library gets consumed with use Slack.API (or Slack.Behaviour, Slack.Client)

[christhekeele]

Slack.State feels pretty weird because all the callbacks end up with a Slack.State and a user-defined state right next to each other in the params.

[BlakeWilliams]

I don't think it's too weird. 'Slack.Client' isn't bad either.