Is it possible to create methods or stand-alone functions in a computation expression that can later be used by one of the canonical methods of a computation expression?
I want something like this:
type FormletBuilder(ctx : HttpContext) =
let get_int =
match Int32.TryParse (ctx.Request.["foo"]) with
| (true, n) -> Some n
| _ -> None
//similar definitions for get_date, get_non_empty_str, etc...
member x.Bind (read : 'a option, f : 'a -> option 'a) =
match read with
| Some x -> f(x)
| None -> None
member x.Return (obj) = Some obj
member x.Zero () = None
let person = formlet ctx {
let! id = get_int "id"
let! name = get_non_empty_str "fullname"
return Person(id, name)
}
But the compiler complains that get_int
is not defined.
let
bindings in class definitions are always private. You can define amember
instead.For an easy solution, you could do: