Motivated by the use of functional programming principles and features for concurrent and distributed programming, this paper proposes enhancements for closures in Scala, called blocks. Blocks increase the flexibility and safety of closures, enabling constraining their environment using types. Blocks support a new approach to serialization based on type classes. The unique design is enabled by new features of Scala 3.

Associate Professor in the School of Electrical Engineering and Computer Science at KTH Royal Institute of Technology in Stockholm, Sweden.