Stewart, Robert <Robert.Stewart <at> sig.com> writes: ... OK, that means we're down to the following now:
1 - default_value<T> customization point 2 - converter<T,S> customization point, main logic, functor 3 - T convert_cast<T,S>(S, formatting = none); can throw 4 - T convert_cast<T,S>(S, T, formatting = none) 5 - bool try_convert_to<T,S>(S, T &, formatting = none) ...
#3, #4. I do not think these can cause any controversy (although people who refuse reading documentation might be surprised by #2 throwing or #3 not throwing ;-) ). #5 IMO can. It deploys the Pascal-style parameter passing and modifications. I remember reading Stroustrup (I think) long time ago advising against passing non-const references and I personally agree. That's due to potential confusion and wrong expectations. I am not aware of any function in std and boost doing that. Introducing such a precedent might be a hard-sell. Especially confusing might be the fact that #4 does not modify the second parameter when #5 does. IMO std::pair<T, bool> try_convert_to<T,S>(S, T, formatting = none) is far less-controversial and even familiar (even though I personally dislike std::pair due to unreadability of the resulting code sprinkled with faceless first and second). Could I suggest convert_result as a more palatable alternative? :-) #1. I am personally not thrilled with default_value because it looks to me like additional/avoidable/arbitrary piece of machinery that I have to implement to incorporate my class into the framework. I've been managing without it. I'd expect a new design not to force me to work harder. Additional note. While you are on the interface, it probably needs to be kept in mind that the current (as I understand it anyway) Boost policy is to avoid introducing content directly in the boost namespace. Therefore, I presume fully qualified it'll be something like int i = boost::conversion::convert_cast<int>(str); So, maybe you might consider shortening it to something like int i = boost::convert::cast<int>(str); or int i = boost::convert::to<int>(str); or int i = boost::convert<int>::from(str); // Just kidding. because otherwise the user will be implicitly forced to namespace cvt = boost::conversion; or worse using namespace boost::conversion; Best, V. P.S. Posting this message via Gmane and it wants me to type 'grouchiness' to confirm. How appropriate. LOL