Getting function name

gettingFunctionName.fs

let getFunctionName f = 
        let type' = f.GetType()
        let method' = type'.GetMethods() |> Array.find (fun m -> m.Name="Invoke")
        let il = method'.GetMethodBody().GetILAsByteArray()
        let methodCodes = [byte OpCodes.Call.Value;byte OpCodes.Callvirt.Value]

        let position = il |> Array.findIndex(fun x -> methodCodes |> List.exists ((=)x))
        let metadataToken = BitConverter.ToInt32(il, position+1) 

        let actualMethod = type'.Module.ResolveMethod metadataToken
        sprintf "%s.%s" actualMethod.DeclaringType.FullName actualMethod.Name