David Abrahams wrote:
dan marsden <danmarsden@yahoo.co.uk> writes:
The ref/cref generation is currently in detail, so library private implementation, and the is_const switch is repeated as with my example. So yes this is a recurring theme, we could provide a utility to do the necessary, but that does not seem to be a feature specific to fusion (as opposed to any other lib that needs to make similar decisions, I believe there is similar code in phoenix for example).
Possibly we could make this decision at a higher level, in deref proper for example, but I'm not sure the logic is appropriate in all cases, such as transform views, were it may be appropriate to return non-const refs from a deref of a const container.
IMO you can do better.
We're considering a utility metafunction that can be used to generate the return type for the various places where element access is required: element_ref<Seq, Element>::type It will then do the add_reference and add_const if needed based on the Seq the element is from. It can then be used to avoid the fiddling above in what I suspect is the common case. Is this sufficient improvement, or did you have something grander in mind? Cheers Dan