Dotty is a platform to try out new language concepts and compiler technologies for Scala. The focus is mainly on simplification. We remove extraneous syntax (e.g. no XML literals), and try to boil down Scala's types into a smaller set of more fundamental constructors. The theory behind these constructors is researched in DOT, a calculus for dependent object types.
####Current status: Technology preview: currently unsupported, may be functionally incomplete or unsuitable for production use.
####Is it going to be the future Scala? Yes, eventually.
####Who's working on it? See github contributors page.
####What are the features that could make me consider trying it?
| Feature | Status |
|---|---|
| Union, Intersection and Literal singleton types | Implemented |
| Fast compilation(phase fusion) | Implemented |
| Trait parameters | Implemented |
| @Static methods and fields | Implemented |
| Colored Repl | Implemented |
| Sbt incremental build | Implemented |
| Non-blocking lazy vals | Implemented |
| Option-less pattern matching(based on name-based patmat) | Implemented |
| Function arity adaptation | Implemented |
| Non-boxed arrays of value classes | In progress |
| Working contravariant implicits | In progress |
| Auto-Specialization | In progress |
| Whole program optimizer | In progress |
| Library defined optimizations | In progress |
| HList & HMaps\Record types | Under consideration |
| Implicit functions | Under consideration |
| Effects | Under consideration |
| Auto-completion in repl | Under consideration |
| Spec Option-less pattern matching | Under consideration |
| Multiverse equality | Under consideration |
| Exhaustivity checks in pattern matching | Under consideration |
| There are also plethora of small details such as per-callsite @tailrec annotations |
####What are the complications that I can have If I start using Dotty?
Dotty can use libraries compiled by scalac 2.11, but Scala scalac can't use libraries compiled by Dotty.
No existential types.
No macro support yet. We have big plans here.
No early initializers. No scala.DelayedInit. Use trait parameters instead.
Whole program optimizer will only work if all dependencies are compiled by Dotty.
####Can I write my code in a way that is going to be compatible with Scalac & Dotty?
Yes, Dotty itself is a project that can be compiled by both Dotty and Scalac.
It's not very hard, and the biggest thing that you will likely miss is using macros.
####How can I try it out?
https://github.com/lampepfl/dotty/wiki/Getting-Started.
Here’s an example sbt project and instructions on how to set it up: https://github.com/smarter/dotty-example-project/
We have colored REPL :-). You can invoke it by running dotc -repl.
####We also have:
Basic support for Scala.js,
Prototype of compilation to x86 native code(Shabalin)
####What about scalac: Scalac is the basis for stability in scala. We expect scalac & dotty to coexist for long time.
####Contributions are welcome!
We invite you to help us build the future of Scala.
This is the best moment to participate, as everyone can make an impact.
####SI-2712? If scalac will put it into 2.12, we’ll mimic their behaviour. But we have bigger plans for HK-types.
Developers mailing list is https://groups.google.com/forum/#!forum/dotty-internals.