namespace System.Reactive.Joins { public class Pattern<TSource1, TSource2, TSource3> : Pattern { internal IObservable<TSource1> First { get; } internal IObservable<TSource2> Second { get; } internal IObservable<TSource3> Third { get; } internal Pattern(IObservable<TSource1> first, IObservable<TSource2> second, IObservable<TSource3> third) { First = first; Second = second; Third = third; } public Pattern<TSource1, TSource2, TSource3, TSource4> And<TSource4>(IObservable<TSource4> other) { if (other == null) throw new ArgumentNullException("other"); return new Pattern<TSource1, TSource2, TSource3, TSource4>(this.First, this.Second, this.Third, other); } public Plan<TResult> Then<TResult>(Func<TSource1, TSource2, TSource3, TResult> selector) { if (selector == null) throw new ArgumentNullException("selector"); return new Plan<TSource1, TSource2, TSource3, TResult>(this, selector); } } }