Algebraic data types for C99

Easy-to-use sum types in Julia

Functional Programming Unorthodoxly Adjusted to Client-/Server-side Javascript

A research programming language on top of C macros

nextgen MLStyle: Generic Algebraic Data Type + Pattern Match

A code generator enabling sum-types in Dart

Easy, fast, transparent generic derivation of typeclass instances in Scala

Sum Data Table dengan Flutter

Fast and memory-efficient immutable collections and helper data structures

Macros for zipping fallible operations together

Monad, Functional Programming features for Golang

THE true generic sum type for Rust

PrimeFuncPack Core.Taggeds is a core pack for .NET consisting of fundamental tagged types targeted for use in functional programming: Optional and Result monads, Tagged Union, as well as the convert extensions.

A general-purpose interpreted programming language implemented in Rust.

An implementation of sum types in Julia

Result, Either, Try, and Maybe monadic types for Java

Expressive High-Performance Eager Functional Programming Library for C++ 11

Minimal core language based on dependent function type, pair type, recursive type, sum type and record type.

Tagged unions for Elixir. Just that.

Elm Either