Re: [boost] Deterimining interest in: Optional Polymorphic Value object with Small Object optimization

Corrado Zoccolo wrote:

as well as providing a well known optimization technique to avoid dynamic allocation when the involved objects are small.

The problem with small object optimization is that you get the same issue that boost.variant has: it's hard to maintain the never-empty guarantee in operator=, because the copy constructor of a new value can throw and thus you lose the old value. I wonder, by the way, how boost.function solves that issue. Apart from that, what does optional_poly<T> give that optional< poly<T>

doesn't, apart from a small save of memory ? Maybe optional should be specialized, rather, to allow it to be more efficient for your type.