Scala Days 2018 Highlights

We went to the Scala Days 2018 in Berlin. The talks we liked the most were:

The Keynote of Adriaan Moors and Martin Odersky. They spoke mostly about Scala 3.0. Some interesting aspects were:

• From 2.14 on Scala will switch to a new binary format called Tasty. Tasty should stay compatible between different Scala Versions and it should be possible to mix Libraries from different Scala Versions.
• To make the step between Scala 2.14 and 3.0 smaller a lot of the new features are already included in 2.13 and 2.14. For example in 2.13 there will be a new Collections Library.
• One of the main targets is to simplify Scala. Some of the planned changes are: a real Enum; Equality will only be possible between compatible Types; APIs which return Null have to be marked.

The Talk «Functional Interpreters and You» is about Free Monad and Finally Tagless. That's a pattern from Functional Programming which helps building DSLs. The advantage of it is that these DSLs can easily be composed and interpreted on different Interpreters.

The last Talk «Type Parameter Power-Up!» shows all the Type Parameters of Scala. (Covariance, Contravariance, Invariance, Upper Bounds, Lower Bounds, View Bounds and Context Bounds.) It also explains how and when they are used.