public IAsyncEnumerator <TSource> GetEnumerator()
{
AsyncIterator <TSource> asyncIterator = _state == AsyncIteratorState.New ? this : Clone();
asyncIterator._state = AsyncIteratorState.Allocated;
return(asyncIterator);
}
public static void Main()
{
Iterator.Test();
Async.Test();
AsyncIterator.Test();
LocalFunction.Test();
Lambda.Test();
Complex.Test();
}
private static async Task Main(string[] args)
{
await AsyncIterator.Demo();
Pattern.Demo();
DefaultInterfaceMember.Demo();
IndiceAndRange.Demo();
UsingStatementSample.Demo();
NullCoalescingAssignmentSample.Demo();
StaticLocalFunction.Demo();
ReadOnlyMember.Demo();
RefStruct.Demo();
StackAllocSample.Demo();
InterpolatedVerbatimString.Demo();
UnmanagedConstraintSample.Demo();
}
/// <summary>
/// Projects each element of an async-enumerable sequence into a new form.
/// </summary>
/// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
/// <typeparam name="TResult">The type of the elements in the result sequence, obtained by running the selector function for each element in the source sequence.</typeparam>
/// <param name="source">A sequence of elements to invoke a transform function on.</param>
/// <param name="selector">A transform function to apply to each source element.</param>
/// <returns>An async-enumerable sequence whose elements are the result of invoking the transform function on each element of source.</returns>
/// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="selector"/> is null.</exception>
public static IAsyncEnumerable <TResult> Select <TSource, TResult>(this IAsyncEnumerable <TSource> source, Func <TSource, TResult> selector)
{
if (source == null)
{
throw Error.ArgumentNull(nameof(source));
}
if (selector == null)
{
throw Error.ArgumentNull(nameof(selector));
}
return(source switch
{
AsyncIterator <TSource> iterator => iterator.Select(selector),
IList <TSource> list => new SelectIListIterator <TSource, TResult>(list, selector),
_ => new SelectEnumerableAsyncIterator <TSource, TResult>(source, selector),
});
