Specialization.fs

module Specialization =
    type ITyped<'T1,'T2> =
        abstract member Run<'T3> : 'T1 -> 'T2

    type private Function<'T1,'T2> = delegate of 'T1 -> 'T2

    let Specialize<'T1,'T2> (algorithm: ITyped<'T1,'T2>) =
        let aT  = typeof<ITyped<'T1,'T2>>
        let def = aT.GetMethod("Run").GetGenericMethodDefinition()
        let dT  = typeof<Function<'T1,'T2>>
        fun (t: System.Type) ->
            let m = def.MakeGenericMethod [| t |]
            let f = System.Delegate.CreateDelegate(dT, algorithm, m)
            (f :?> Function<'T1,'T2>).Invoke

(*
Specialization.Specialize
    { new Specialization.ITyped<unit,string> with
        member this.Run<'T>(_) =
            typeof<'T>.Name
    }
    typeof<string>
    ()
*)