/// <summary>
/// Creates a surrogate of the function delegate, which enables double dispatch in the concrete type of its target
/// </summary>
public static Func <T, TResult> CreateSurrogate <T, TResult>(Func <T, TResult> function, T prototype, Func <TResult> orElse, TResult defaultResult)
{
function = function ?? throw new ArgumentNullException(nameof(function));
var target = function.Target ?? throw new ArgumentException("must be bound", nameof(function));
var dispatch = new DoubleDispatchObject(target);
var methodName = function.GetMethodInfo().Name;
Func <T, TResult> surrogate =
arg =>
dispatch.Via(methodName, arg, orElse, defaultResult);
return(surrogate);
}
/// <summary>
/// Creates a surrogate of the action delegate, which enables double dispatch in the concrete type of its target
/// </summary>
public static Action <T> CreateSurrogate <T>(Action <T> action, T prototype, Action orElse)
{
action = action ?? throw new ArgumentNullException(nameof(action));
var target = action.Target ?? throw new ArgumentException("must be bound", nameof(action));
var dispatch = new DoubleDispatchObject(target);
var methodName = action.GetMethodInfo().Name;
Action <T> surrogate =
arg =>
dispatch.Via(methodName, arg, orElse);
return(surrogate);
}