Tab completion on remote console

[ConnorRigby]

IO servers can have their own tab expansion handlers:

fun = fn(str) ->
  {:yes, 'aa', ['aa1', 'aab', 'aac']}
end
:io.setopts(:expand_fun, fun)

We can use this to tunnel tab completion for the remote console

[ConnorRigby]

and here is the Elixir implementation. It should be easy to take this exact code for the remote console, then it's just a matter of capturing the tab event from javascript

[jjcarstens]

Going this route will mean we'll need to get more specific in how we handle IO in the channel because we currently ignore all setopts functions.

But, I'm pretty sure we can set this before reassigning group leader. In fact, I'm also fairly sure this is already set for us by using IEx.Server.run.

Also, I believe another issue to overcome here is that using IEx.Server.run starts a loop with IO.gets, which in turn calls to :io.get_line - The get_line is always expecting a full line at a time and evaluates the input as a whole so we can't really get tab events into it to run the evaluator. I don't have a solution, but I'm really confident that is part of the problem

[jjcarstens]

Also adding a note to consider IEx history (responding to up/down keys from web) here as well since that is likely very related. If it ends up being a different path, we can split out the issue

[fhunleth]

Tab completion works on the new console!!