Would the async experiment also imply better interop between .NET languages?
One issue I’ve heard from F# devs was the lack of ability to comfortably call C# asynchrony methods
One issue I’ve heard from F# devs was the lack of ability to comfortably call C# asynchrony methods
This is no longer the case starting with F# 6: https://learn.microsoft.com/en-us/dotnet/fsharp/whats-new/fs... C# and F# can now transparently interoperate using the same main Task<T> type (in the past, this was done via community libraries for C#->F#, and F#->C# was always possible with |> Async.AwaitTask).
For advanced usage scenarios, there also exist https://github.com/fsprojects/FSharp.Control.TaskSeq and https://github.com/TheAngryByrd/IcedTasks
> Would the async experiment also imply better interop between .NET languages?
This is a good question. If a language already uses Task<T> and ValueTask<T>, the interop is already a solved problem (like with F#). However, this could allow to completely remove or at least significantly simplify the implementation for emitting state machines / resumable code / coroutines for asynchronous methods for any language that targets .NET 10+ (it will most likely get into 10 but is not guaranteed yet from what I've heard).
For example, a guest language could simply choose to emit calls to async methods with special modreq(?) attribute and the runtime would handle suspension, creating the closure for the state captured by asynchronous continuation and then subsequent resumption without any additional work of that guest language to be async-compatible. You could likely even write that by hand in IL with ILAsm. This is a significant improvement for a .NET as a hosting platform, and arguably makes it better than JVM at some high-level scenarios (because for low-level it already supports almost the entirety of what is expressible with C plus struct generics, and for FP it supports tail. prefix for call* opcodes for mandatory tailcalls required by recursive functions).
And for those in the camp of "function coloring considered harmful" (which I'm not a fan of but to each their own), you could even have a guest language that completely hides the fact that it performs such async calls underneath.