Thomas Heller-7 wrote:
On Wed, May 25, 2011 at 10:44 AM, Vicente Botet <vicente.botet@wanadoo.fr> wrote:
Stewart, Robert wrote:
Vicente Botet wrote:
Stewart, Robert wrote:
auto f(factory<short>(_1)); short const s(f(static_cast<long>(3)));
Your suggestions for the "factory" call are:
A. boost::make_converter_to<short>(_1) B. boost::conversion::fp::convert_to<short>(_1) C. boost::convert_to<short>(_1)
I definitely dislike B. A isn't bad, but it should be in the boost::conversion namespace. C is very nice, but it should be in the boost::conversion namespace. The introduction of the placeholder is enough to signal that the result is a Phoenix lambda.
Even if C is the more elegant, to my taste, it introduce a dependency on Boost.Phonix even if functors are not used, and this is one thing I would like to avoid. So it seems that A is a best compromise.
That overload can be put into a separate header so it, and its dependency on Phoenix, is only visible when desired. <boost/conversion/functor.hpp>?
Hi,
this independent overloading could be done if there was a class placeholder, but in Phoenix a placeholder is a concept, isn't it. So the overloading can be done only using SFINAE, which implies that one overload works for T that are placeholders and the otherfor T that are no placeholders.
Let me know if I'm missing something.
FWIW, a phoenix actor is a concept, yes. The file boost/phoenix/core/is_actor.hpp has only a dependency on the boost/mpl/bool.hpp header. So including this might not really add to much dependency on your code.
Another possibility certainly is to create your own trait:
template <typename T, typename Enable> struct enable_functor : mpl::false_ {};
or something, that gets specialized on phoenix::is_actor once your user includes the header that enables functors. Using this, you gain another point of flexibility by being able to support other functional style libraries.
Thanks for your clever suggestion. I will adopt it. Best, Vicente -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-Conversion-functors-namming-tp35240... Sent from the Boost - Dev mailing list archive at Nabble.com.