New typeclass derivation library for Scala 2 and 3

With this talk and library I wanted to create a high performance typeclass derivation library that worked equally for Scala 2 and 3.

Source code at Sam Halliday / shapely · GitLab

Slides at Shapely

A shame that @deriving doesn’t work on both Scala 2 and 3 because that would have made for an excellent way to migrate to 3 in increments, and even cross build for a time. Let’s keep chat about that particular aspect to Pre-typer syntactic plugins in Scala 3? - Dotty - Scala Contributors