public static T Factorial <T>(
this IExpressionEvaluator <T> evaluator,
T @base
) where T : struct, IComparable <T>, IEquatable <T>
{
var sequence = evaluator.Sequence(
@base,
(ev, n, i) => ev.Subtract(n, ev.GetValue(1)),
(ev, n, i) => n.CompareTo(ev.GetValue(0)) > 0
);
var result = evaluator.Product(sequence);
return(result);
}
