Effekt Language: a research language with effect handlers and lightweight effect polymorphism written in #scala
-Lightweight Effect Polymorphism, No need to understand effect polymorphic functions or annotate them. Explicit effect polymorphism simply does not exist.
-Effect Safety, A type- and effect system that does not get into your way. Rely on a simple, yet powerful effect system that guarantees all effects to be handled.
- Effect Handlers, (Algebraic) effect handlers let you define advanced control-flow structures like generators as user libraries. Those libraries can be seamlessly composed.
https://effekt-lang.github.io/effekt-website/
-Lightweight Effect Polymorphism, No need to understand effect polymorphic functions or annotate them. Explicit effect polymorphism simply does not exist.
-Effect Safety, A type- and effect system that does not get into your way. Rely on a simple, yet powerful effect system that guarantees all effects to be handled.
- Effect Handlers, (Algebraic) effect handlers let you define advanced control-flow structures like generators as user libraries. Those libraries can be seamlessly composed.
https://effekt-lang.github.io/effekt-website/
Reimagining Functional Type Classes in #scala
A great talk about how functional abstraction can be reimagined. I personally learned a lot from it.
It also features new ZIO Prelude library.
A great talk about how functional abstraction can be reimagined. I personally learned a lot from it.
It also features new ZIO Prelude library.
YouTube
SF Scala: Reimagining Functional Type Classes
ai.bythebay.io Nov 2025, Oakland, full-stack AI conference For decades, the Functor, Monoid, and Foldable type class hierarchies have dominated functional programming. Implemented in libraries like Scalaz and Cats, these type classes have an ancient origin…
Flix: Next-generation reliable, safe, concise, and functional-first programming language.
Flix is inspired by OCaml and Haskell with ideas from Rust and Scala. Flix looks like Scala, but its type system is based on Hindley-Milner. Two unique features of Flix are its polymorphic effect system and its support for first-class Datalog constraints.
Flix aims to offer a unique combination of features that no other programming language offers, including: algebraic data types and pattern matching (like Haskell, OCaml), extensible records (like Elm), type classes (like #haskell, #rust), higher-kinded types (like Haskell), local type inference (like Haskell, OCaml), channel and process-based concurrency (like #go), a polymorphic effect system (unique feature), first-class Datalog constraints (unique feature), and compilation to JVM bytecode (like #scala).
https://flix.dev/
Personal opinion: it has all the features new modern programming language should have. It has nice syntax, powerful ideas, and (hopefully) good JVM integration and code-reuse. That's a recipe for a success. I will keep an eye on this amazing language.
It also has a playground on its website, check it out!
I would love to highlight this example of polymorphic effects:
Flix is inspired by OCaml and Haskell with ideas from Rust and Scala. Flix looks like Scala, but its type system is based on Hindley-Milner. Two unique features of Flix are its polymorphic effect system and its support for first-class Datalog constraints.
Flix aims to offer a unique combination of features that no other programming language offers, including: algebraic data types and pattern matching (like Haskell, OCaml), extensible records (like Elm), type classes (like #haskell, #rust), higher-kinded types (like Haskell), local type inference (like Haskell, OCaml), channel and process-based concurrency (like #go), a polymorphic effect system (unique feature), first-class Datalog constraints (unique feature), and compilation to JVM bytecode (like #scala).
https://flix.dev/
Personal opinion: it has all the features new modern programming language should have. It has nice syntax, powerful ideas, and (hopefully) good JVM integration and code-reuse. That's a recipe for a success. I will keep an eye on this amazing language.
It also has a playground on its website, check it out!
I would love to highlight this example of polymorphic effects: