Orsak

eff {
    let! line = Effects.Console.readLine()
    do! Effect.Console.writeLine $"Hello {line}"
}

Orsak is a library for function effects in F#, allowing pragmatic and composable modelling of side-effects through interfaces. It is inspired by Zio, with F# encoding similar to the approach described by Bartosz Sypytkowski here.

However, Orsak is not intended to be a framework. Rather, it is encouraged and recommended to make use of the existing .NET ecosystem, and Orsak is intended to make that as easy and friction-free as possible. It can be used piecemeal, and introduced to existing codebases in isolated chunks.

This implementation makes use of resumable code to implement the computation expression builder for the lowest possible overhead. The builder also has various overloads for Bind, allowing for friction free interop with TaskLike<'a>, Async<'a>, Result<'T,'E> and more. It supports for, while, use, try-with and try-finally, and also applicative bind when the error-type supports +. While the computation expression is the intended way of working with effects, the corresponding module should contain all the expected functions.