How to have a static member on a record type that is only evaluated once?

General
1

Consider the following snippet:

let rnd = Random()

type Schema = private { Value : string }
    with
        static member create (typ:Type) : Schema =
            {
                Schema.Value = rnd.Next().ToString()
            }

type Test = { value : string }
    with
        static member Schema : Schema =
            printfn "me"
            Schema.create typeof<Test>

let s1 = Test.Schema
printfn "%A" s1
let s2 = Test.Schema
printfn "%A" s2

What I’d like to have is the Schema static member on Test evaluated only a single time. Is there any way to accomplish this with record types? Or is using the class syntax (type Test() = ...) the only way?

2

Have you considered using a lazy value? Eg.

let backingField =
    lazy (
        printfn "constructing value"
        "hi"
    )

let sayHi() = backingField.Force()

sayHi() // prints "constructing value"
sayHi() // doesn't print