Roadmap V2.0

I think for V2.0 we can start discussing features here, before moving to a formal project.

What comes to my mind at the moment is:

1. Remove subsumption from Applicatives: Right now seq “eats” all custom types implementing seq

2. Same for Traversable, same situation: although this might not require a breaking change (todo find out)

3. Implement IEnumerable for Vectors, now that (1) has to be done.

4. New ListT monad transformer, possibly new SeqT as well, coded using a similar technique as the one used for Free Monads.

5. Review computation expressions: autosense will be removed but we have to do something to make it easy for users to understand why a strict monad can’t be used with the non-strict CE. Maybe make compilation fail when calling a TryWith?

6. Add ValueTuple, ValueTask and other latest addition to the framework. We can require a higher framework version

7. Consider suggestions by @dsyme regarding using the return type for type inference.

Am I missing something?

EDIT

1. Better task support (maybe an intermediate type like Step with conversions to/from Task and its use in Bind an other methods for task).

2. Consistent type parameters order, this would need to swap type parameters in Validation<'err,'t> to Validation<'t,'err>.

[gusty]

I’m a bit ambivalent about splitting the library.

It’s true, some users would like to see the extensions in a separate library, @dsyme for instance told me he likes that part of the library and would love to see it as a separate thing.

Let’s discuss that option in its corresponding issue https://github.com/fsprojects/FSharpPlus/issues/328#issuecomment-704095824 and assume in this discussion that the library will continue as a whole.

[gusty]

To avoid using SRTPs on the result type, unless it’s the only way (ie: return, zero, maxValue).

We can try remove it in other functions, I’m sure it will be a breaking change, so we’ll have to measure the impact and see if it worths.