Implement async handling option: "async" | "task" for the fsharp target

[Zaid-Ajaj]

Basically:

{
   ["asyncReturnType"]: < "async" | "task" >
}

Where async is the default. To make the generated functions either return Async<'T> or Task<'T>

For the latter you would need to include Ply as a dependency to the generated F# project.

Related to #29

Might need a better API for generating the projects and their packages.

[Numpsy]

Is Numpsy@d4f91f7 the right sort of thing?

Notes:

• I'm largely making it up as I go along, and am not certain what stringBuffer is giving you in some cases.
• Is Async.AwaitTask/Async.RunSynchronously the approach you'd want with tasks? (When I've done the sync-over-async thing with tasks in C# it was using the GetAwaiter().GetResult() type approaches, not sure what the best approach is in F#).

[Zaid-Ajaj]

@Numpsy you are on the right track, here is a checklist from the top of my head:

• don't worry about stringBuffer, it just concatenates the strings
• when checking if isNull parsedJson.["asyncReturnType"] || string parsedJson.["asyncReturnType"] = "async", the expression string parsedJson.["asyncReturnType"] should be lower-cased (same when validating)
• should return a parse error if asyncReturnType = task && target = fable because Fable doesn't support tasks
• should include nuget Ply @ v0.3.1 when asyncReturnType = task
• should open namespace FSharp.Control.Tasks when asyncReturnType = task (namespace from Ply)
• Using GetAwaiter().GetResult() for sync sounds good. It doesn't matter that much, both should work fine (if it is easier to leave it as is, I am fine with that)

[Numpsy]

* don't worry about stringBuffer, it just concatenates the strings

I'd thought it did, but then it looked like some of the existing uses only contain a single string, so I wasn't sure if I was missing something :-(

* when checking `if isNull parsedJson.["asyncReturnType"] || string parsedJson.["asyncReturnType"] = "async"`, the expression `string parsedJson.["asyncReturnType"]` should be lower-cased (same when validating)

Hmm, I copied that from the existing code @

Snowflaqe/src/Program.fs

Line 106 in c02fd6e

if isNull parsedJson.["target"] || string parsedJson.["target"] = "fable"

and had missed that it lower cases the string when validating and not when using it (so it seems that setting target to Fable (capital F) with the current release actually causes it to generate a Shared Project (is that considered a bug then?)

* Using `GetAwaiter().GetResult()` for sync sounds good. It doesn't matter that much, both should work fine (if it is easier to leave it as is, I am fine with that)

Doing GetAwaiter().GetResult() directly on the task returned from the Async function should be straight forward, but I had a go at calling it through Task.Run instead and got some overload resolution errors, so sticking to the F# functions which just worked was easier (too many ways of doing the same thing!)

[Zaid-Ajaj]

and had missed that it lower cases the string when validating and not when using it (so it seems that setting target to Fable (capital F) with the current release actually causes it to generate a Shared Project (is that considered a bug then?)

Yes, that's a bug!

[Numpsy]

Considered resolved by merging #47 ?

I'd wondered about adding CancellationToken parameters to the Task returning variants of the functions, but that could be a seperate change if needed.

[Zaid-Ajaj]

This is resolved and tested locally! thanks a lot @Numpsy ❤️ you can try this out as of v1.26

[Zaid-Ajaj]

Let's worry about the cancellation token in a different issue 😉