Merge pull request #599 from fommil/gsoc-2017

GSoC ENSIME debugger and data annotation

Author: julienrf

gsoc/2017.md

@@ -81,6 +81,57 @@ or Dotty) to identify what can be re-used.
 
 Supervised by [@densh](http://github.com/densh)
 
+### Scala Debugging in ENSIME
+
+ENSIME is a kind of scala language server and has the potential to
+provide all text editors with a compelling debugging experience in
+Scala.
+
+The experimental ENSIME debugger has problems: breakpoints often miss
+and heuristics - to convert between scala and JVM bytecode names -
+often fail. There is no support for scala expression evaluation in the
+debugging context.
+
+In this project we would rewrite the debugger to make use of ENSIME's
+name conversion utilities (powered by the scalac interactive
+compiler), add expression evaluation, and the user interface
+for (at least) one of the editors. The candidate is free to choose to
+implement for either Emacs, VSCode, Vim, Atom or Sublime.
+
+http://ensime.org/
+
+Supervised by *[@fommil](https://github.com/fommil)* and
+*[@chipsenkbeil](http://github.com/chipsenkbeil)*.
+
+### Case classes a la carte with scala.meta
+
+`case class`es are a very useful feature of the scala language, but
+can be limiting. For example, there is no way to write a custom
+interning (memoization) technique or modify the internal
+representation of a case class, leading to heap usage problems for
+larger applications that generate hundreds of millions of instances (a
+common problem in monolithic financial services applications).
+
+In this project we would introduce a `@data` annotation, as a
+user-land alternative to `case class`. The default implementation
+would have feature parity with `case class` but opt-in features
+include: interning (backed by a fast, concurrent, weak hashset,
+allowing for super-fast instance equality), hashCode caching, fast
+value equality (backed by instance ids and a cache of previous
+equality tests), unboxing of Options and primitives (each unbox saving
+64bits per instance), all the way to FastInfoSet-style custom
+compression dictionaries (e.g. for Strings).
+
+Another usecase would be to allow for automatic typeclass derivation
+of well-known typeclasses, placed on the companion. e.g.
+`LabelledGeneric`, `Show`, `Lens`. This would speed up compilations of
+downstream code (for example, currently shapeless uses a macro to
+generate a `LabelledGeneric` for a case class on every usage site, but
+with this approach there is no derivation necessary).
+
+Supervised by *[@fommil](https://github.com/fommil)* with support from
+*[@xeno-by](https://github.com/xeno-by)*.
+
 ### Dotty Documentation Compiler ###
 
 [Dotty](http://dotty.epfl.ch) is the future Scala compiler developed at EPFL.