Is it possible to add concrete implementation of monad for IObservable<'a> ?

Currently IObservable<'a> works fine with map / |>>, but does not work with monad CE.

Since IObservable<'a> has LINQ extension methods IObservable.Select, IObservable.SelectMany and Observable.Return. It seems that it might be nature to have monad instance just following System.Reactive.Linq 's implementation.

As discussed in here, adding concrete implementation for IObservable<'a> in FSharpPlu.Control might be the easiest way to achieve this.

Is it possible to add monad instance concrete implementation directly to F#+?

If there is no other constrains, adding concreate implementation in Control/Monad.fs might be as easy as several lines of code to direct call IObservable<'a>'s corresponding extension methods.

But there might be some problems, like introduce dependency to System.Reactive, and maybe Using / Defer and other methods needs also be considered. But considering IObservable<'a> is already provided in System namespace, and Rx.Net is an popular functional style library, solving these problems might have enough benefits.

Start in Control/Monad.fs and compare the existing monad CE support with System.Reactive.Linq's IObservable.Select, SelectMany, and Observable.Return. Determine whether a concrete IObservable<'a> instance belongs there without an unplanned System.Reactive dependency, and consider the mentioned Using and Defer methods. Done means the supported scope and dependency approach are resolved.