LiveScript "2.0"

"It's a-boot time"

So, this got talked about quite about before, but I'm not sure that's actually what's interesting to us now.

However, there's definitely a need to cleanup some things in LS, and especially with ES6/7-related.

Are people okay with breaking changes now? If they're not, we can discuss what we want to change, but in the meantime:

• Implement type ascriptions (PR starting Start working on type ascriptions #803)
• ES6 support:
  • modules. @gkz proposed import! and export! for the ÈS6 modules (we need to decide between <<<{<,} and import {all,} anyway)
  • classes: I don't think we want them. LiveScript code tends to use invokable class bodies
  • async/await can be delayed a bit more, I think. It's ES7, and it's not quite there yet... We'd also need to decide on a syntax (eww ->**)
  • const needs to be compiled to ES6's const
  • I'm not sure we need to change let's meaning, I don't think it adds much.
• Remove for ever
• Parse the star as a real operator (not just void=)
• Remove implements (unless people actually use it)
• Remove the match-introduced operators >== etc
• Make match an actual pattern matching operation (semantics TBD, that can come later)
• Remove operator overloading (...or make the compiler aware of types...)
• Trim down synonmys. Includes otherwise/default, case/when, =>/then (I guess this one is the one people like), etc

This will be controversial (at best), but I think it's worth discussing:
I believe we should remove implicit variable declaration. We have var, and := when we need to change a value.
I think the scoping rules would seem much saner if we had to explicitly declare those. But I know this isn't going to fly for a lot of people, so...

There's another controversial topic: .., it and that. I like what we currently have, but I'm too biased to know if that bugs people or not.