Implement Elchemy REPL

[wende]

Functionality:
A REPL should take single lines of Elchemy, and produce an output of compiled Elixir code:

Examples:

elchemy> 2 + 5
7
elchemy> List.map ((+) 2) [1,2,3]
[3,4,5]
elchemy> Just 10
{10}
elchemy> Nothing
nil

Ideas:

• Autocompletion on Tab press (Can be Elixir autocompletion since the syntax of variables and Module.function is the same)
• Display compiled Elixir code when demanded
• Compile the output back to Elchemy syntax (?)
• Display the type of the output (?)

Possible implementation:

• Node.js process wrapper around iex. Using Elchemy functions to compile String in and feed them out to wrapped process.
• Listen for tab key and either send tab key to the process or use IEx.Autocomplete module

[wende]

For output clarity probably #93 is a must

[wende]

Blocked by #164

[wende]

Not worth the effort. Closing in favor of #207

[wende]

Resurrecting for discussion on possible implementations

[wende]

I think there's an option to hack this pretty easily:

1. Write a simple Repl.elm file in Elchemy that understands the input to the repl and translates into related Elixir code
   a) If it looks like statement add to a module and reload the whole thing
   b) If it looks like expression treat it as a query and only print the output
2. Download the whole Elchemy codebase
3. Write an expect script to feed input information into elm repl launched in Elchemy codebase directory, and pass it further into Repl.input() function.
4. If there were no errors take the output of code produced and feed it to iex repl
5. Print out the result of both repl's (iex result and elm-repl type result) to the interface
6. ???
7. Profit

[wende]

Would be way easier to ship if #352 was done