I have a question over on Code Review SE where I’m struggling to work out how to refactor my enumerator method to be less of a complete mess.

I think part of the problem is I can’t work out how to call other methods from inside it and have them yield results without having to wrap that inner call inside a foreach and yeild out the items one by one.

Is there any way to do some sort of multi-yield in C# so that this would work?

    private IEnumerable<int> Outer()
    {
        yield return 0;
        yield return Inner(); // Some sort of multi-yield
        yield return 5;
    }
    
    private IEnumerable<int> Inner()
    {
        yield return 1;
        yield return 2;
        yield return 3;
        yield return 4;
    }

I know I can do this, but this isn’t what I’m looking for as by the time I’ve done this a few times, my refactored version wouldn’t be much better:

    private IEnumerable<int> Outer()
    {
        yield return 0;
        foreach (int i in Inner())
        {
            yield return i;
        }
        yield return 5;
    }