On 28 Jun 2015 at 21:05, Michael Marcin wrote:
I mean: result<T, E> is like "give me T or it's an error". There is no empty state. Empty would already be an error state. I'd only understand empty if it's an async operation that didn't finish already.
What's the state of a default constructed result<T, E>?
Is it an error state? Is it empty? Or is it not default constructible?
In my dirty monad, result<T> (there is no result<T, E>) is always default constructed to empty. If you want it constructed to something else, simply pass that into its constructor. There is also a make_monad(T/error_code/exception_ptr). In Rust's Result<T, E>, there is no default construction. You must choose either a T or a E at the point of construction, failure to do so is a compile time error. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/