public void ChainFallbacksTest()
{
int callsToFirst = 0, callsToSecond = 0;
VariadicArrayParametersDelegate
first = args => { throw new Exception($"{++callsToFirst}"); },
second = args => { callsToSecond++; return(4); };
Assert.AreEqual(expected: 0, actual: callsToFirst);
Assert.AreEqual(expected: 0, actual: callsToSecond);
var result = new[] { first, second }.ChainFallbacks();
Assert.AreEqual(expected: 0, actual: callsToFirst);
Assert.AreEqual(expected: 0, actual: callsToSecond);
Assert.Throws <Exception>(() => first());
Assert.AreEqual(expected: 1, actual: callsToFirst);
Assert.AreEqual(expected: 0, actual: callsToSecond);
Assert.AreEqual(expected: 4, actual: second());
Assert.AreEqual(expected: 1, actual: callsToFirst);
Assert.AreEqual(expected: 1, actual: callsToSecond);
Assert.AreEqual(expected: 4, actual: result());
Assert.AreEqual(expected: 2, actual: callsToFirst);
Assert.AreEqual(expected: 2, actual: callsToSecond);
Assert.AreEqual(expected: 4, actual: result());
Assert.AreEqual(expected: 2, actual: callsToFirst);
Assert.AreEqual(expected: 3, actual: callsToSecond);
}
public void DelegateWrappingTest()
{
VariadicArrayParametersDelegate del = args => (int)args[0] + (int)args[1];
Func <int, int, int> wrapped = del.WrapDelegate <Func <int, int, int> >();
int result = wrapped(30, 12);
Assert.AreEqual(expected: 42, actual: result);
}
internal static VariadicArrayParametersDelegate CreateLazy(this Func <VariadicArrayParametersDelegate> creator)
{
VariadicArrayParametersDelegate delegat = null;
return(args => {
if (delegat == null)
{
delegat = creator();
}
return delegat.Invoke(args);
});
}
public void CreateLazyIsLazyTest()
{
int creationCount = 0;
Func <VariadicArrayParametersDelegate> creator = () => {
creationCount++;
return(args => "success!");
};
Assert.AreEqual(expected: 0, actual: creationCount);
VariadicArrayParametersDelegate delegat = creator.CreateLazy();
Assert.AreEqual(expected: 0, actual: creationCount);
Assert.AreEqual(expected: "success!", actual: delegat.Invoke());
Assert.AreEqual(expected: 1, actual: creationCount);
Assert.AreEqual(expected: "success!", actual: delegat.Invoke());
Assert.AreEqual(expected: 1, actual: creationCount);
}
/// <summary>
/// Constructs a delegate of type <typeparamref name="D"/> that calls the given <see cref="VariadicArrayParametersDelegate"/>.
/// </summary>
/// <remarks>
/// Uses <see cref="Expression{TDelegate}.Compile"/> internally, but only once for each type <typeparamref name="D"/>
/// provided.
/// </remarks>
public static D WrapDelegate <D>(this VariadicArrayParametersDelegate delegat) where D : class
{
var builder = builders.GetOrAdd(typeof(D), (Type t) => getBuilderExpression <D>().Compile());
return((D)builder(delegat));
}
