Von: Andrzej Krzemienski [via Boost] [mailto:ml-node+s2283326n4677451h87@n4.nabble.com] Gesendet: Montag, 22. Juni 2015 20:54 An: Löw, Tobias (STEAG Energy Services GmbH) Betreff: Re: [Optional] Monadic bind 2015-06-22 16:59 GMT+02:00 Tobias Loew <[hidden email]</user/SendEmail.jtp?type=node&node=4677451&i=0>>:
I deliberately used this std::bind syntax since it accepts any callable (including things like pointer-to-member [functions]). I tried lambdas with my code and they just work. E.g.
auto opt_i3 = map(opt_a, [](const A& a){ return a.i;}); assert(*opt_i3 == 42);
Interesting. Is it implementable in C++03? I managed to change your map2 to compile in C++03 (on VS 2008) template <typename T, typename F> boost::optional< typename boost::remove_cv< typename boost::remove_reference< typename boost::result_of<F(T)>::type >::type >::type > map2(const boost::optional<T>& o, F f) { if (o) return f(*o); else return boost::none; } I didn’t find an easy way to make my map compile in C++03. Technically, it should be possible by using the same tricks that boost::bind itself uses, but I think that would be by far too much for such a feature. A good solution could be: using a map2-like version (only accepting functions/functors) for C++03 compilers and a the more general version (accepting arbitrary callables) for C++11 compilers. -- View this message in context: http://boost.2283326.n4.nabble.com/Optional-Monadic-bind-tp4677431p4677464.h... Sent from the Boost - Dev mailing list archive at Nabble.com.