Basic IoC using DI in F#

BasicIoC.fsx

#r "nuget: Microsoft.Extensions.DependencyInjection"
#r "nuget: Microsoft.Extensions.Hosting"

open Microsoft.Extensions.DependencyInjection
open Microsoft.Extensions.Hosting

type Foo = { Foo : string }
type Bar = { Bar : int }
type FooBar = Foo -> Bar

let fubar : FooBar =
    fun (foo:Foo) ->
        { Bar = System.Int32.Parse foo.Foo }

type IServiceCollection with
    member this.AddFooBar() =
        this.AddSingleton<FooBar>(fubar)

let host =
    Host.CreateDefaultBuilder(fsi.CommandLineArgs)
        .ConfigureServices(fun services -> services.AddFooBar() |> ignore<IServiceCollection>)
        .Build()

let myFubar = host.Services.GetRequiredService<FooBar>()
myFubar { Foo = "42" } |> printfn "%A"