Re: [boost] [next gen future-promise] What to call the monadic return type?

Vicente J. Botet Escriba wrote:

I see that you want to be able to store error_code or exception_ptr. Wouldn't the interface of expected> be enough?

future<T> already adds the ability to store exception_ptr. There is no need to store another exception_ptr in the value. Niall's type is exactly equivalent to future>, as I already said (twice).

I proposed to the C++ standard a function future<T>::next (bind) that takes a continuation having T as parameter (future<R>(T)), and and future<T>::catch_error that takes a as parameter a continuation that takes an errror as parameter. The proposal was not accepted.

future<T>::next( [](T){...} ) is actually pretty useful, catch_error() much less so. You should have proposed just the former. (Sean Parent's future implementation's ::then has ::next's semantics IIRC.)