Why create a new enumerator type instead of returning collection?

[shmuelie]

In the MemoryFileSystem, when enumerating paths, the contents of the SortedSet<UPath> are returned using a foreach with a yield instead of simply returning the SortedSet<UPath> itself. Any reason for this?

[xoofx]

Yes, that's because SortedSet<UPath> is valid for a single folder, and we can visit all folders:

https://github.com/xoofx/zio/blob/87c7172ff63f4fb4785af2f0437485be7043c80e/src/Zio/FileSystems/MemoryFileSystem.cs#L770

[shmuelie]

Ah yes, I missed where the loop was happening, thought it was outside the while. Thanks!