Composing Contracts Part 1: Data Types

module ContractDataTypes

open System

open System.Linq

type Date = Date of DateTime

type Days = Days of TimeSpan

type Currency = GBP | USD

type Money = Money of float * Currency

    with static member (*) (k, Money (v, c)) = Money (k * v, c)

type Contract = | One of Currency

                | Scale of (IObservable<double> * Contract)

                | When of (IObservable<bool> * Contract)

type RxBuilder() =

    member this.Bind(m:IObservable<'a>, f:'a -> IObservable<'b>) =

        Observable.SelectMany(m, new Func<'a, IObservable<'b>> (f))

    member this.Return x = Observable.Return x

    member this.ReturnFrom x = x

    member this.Zero() = Observable.Empty()

let rx = RxBuilder()