lcaminiti wrote
I will use the lib in some use cases that I ran into the past and let you know if I find a nice example not too complex (I don't remember what the use cases were but they were about type erasure).
Why this does not compile? #include <boost/type_erasure/any.hpp> #include <boost/type_erasure/builtin.hpp> #include <boost/type_erasure/operators.hpp> #include <boost/mpl/vector.hpp> #include <iostream> struct display { public: template< typename T > explicit display ( T const& obj ) : obj_(obj) {} public: void print ( void ) { std::cout << obj_ << std::endl; } private: boost::type_erasure::any< boost::mpl::vector< boost::type_erasure::copy_constructible<> , boost::type_erasure::typeid_<> , boost::type_erasure::ostreamable<> > > obj_; }; int main ( void ) { display i(123), s("abc"); i.print(); s.print(); return 0; } Using GCC 4.5.3 on Cygwin with Boost 1.50.0 Beta 1, I get: In file included from ../boost/type_erasure/detail/access.hpp:14:0, from ../boost/type_erasure/any.hpp:34, from 01.cpp:2: ../boost/type_erasure/detail/storage.hpp: In constructor ‘boost::type_erasure::detail::storage::storage(const T&) [with T = char [4]]’: ../boost/type_erasure/any.hpp:167:22: instantiated from ‘boost::type_erasure::any<Concept, T>::any(const U&) [with U = char [4], Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<>, boost::type_erasure::typeid_<>, boost::type_erasure::ostreamable<> >, T = boost::type_erasure::_self]’ 01.cpp:11:49: instantiated from ‘display::display(const T&) [with T = char [4]]’ 01.cpp:26:28: instantiated from here ../boost/type_erasure/detail/storage.hpp:24:44: error: ISO C++ forbids initialization in array new In file included from ../../../1_50_0_beta1.cygwin/boost/preprocessor/iteration/detail/iter/forward1.hpp:52:0, from ../boost/type_erasure/detail/rebind_placeholders.hpp:127, from ../boost/type_erasure/detail/normalize.hpp:31, from ../boost/type_erasure/any.hpp:36, from 01.cpp:2: ../boost/type_erasure/detail/rebind_placeholders.hpp: At global scope: ../boost/type_erasure/detail/rebind_placeholders.hpp: In instantiation of ‘boost::type_erasure::detail::rebind_placeholders_in_argument<boost::type_erasure::_self(const boost::type_erasure::_self&), boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >’: ../boost/type_erasure/detail/rebind_placeholders.hpp:149:63: instantiated from ‘boost::type_erasure::detail::rebind_placeholders<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >’ ../boost/type_erasure/detail/adapt_to_vtable.hpp:53:7: instantiated from ‘boost::type_erasure::detail::rebind_placeholders<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >’ ../../../1_50_0_beta1.cygwin/boost/mpl/aux_/has_type.hpp:20:1: instantiated from ‘const bool boost::mpl::aux::has_type<boost::type_erasure::detail::rebind_placeholders<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >, mpl_::bool_<true>
::value’ ../../../1_50_0_beta1.cygwin/boost/mpl/aux_/has_type.hpp:20:1: instantiated from ‘boost::mpl::aux::has_type<boost::type_erasure::detail::rebind_placeholders<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >, mpl_::bool_<true> >’ ../../../1_50_0_beta1.cygwin/boost/mpl/aux_/preprocessed/gcc/quote.hpp:56:5: instantiated from ‘boost::mpl::quote2<boost::type_erasure::detail::rebind_placeholders, mpl_::void_>::apply<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >’ ../../../1_50_0_beta1.cygwin/boost/mpl/aux_/preprocessed/gcc/apply_wrap.hpp:49:1: [ skipping 14 instantiation contexts ] ../../../1_50_0_beta1.cygwin/boost/mpl/transform.hpp:138:1: instantiated from ‘boost::mpl::transform<boost::mpl::v_item<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::ostreamable<>, void(std::basic_ostream<char>&, const boost::type_erasure::detail::storage&)>, boost::mpl::v_item<boost::type_erasure::typeid_<>, boost::mpl::v_item<boost::type_erasure::destructible<boost::type_erasure::_self>, boost::mpl::v_item<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::mpl::vector0<mpl_::na>, 0>, 0>, 0>, 0>, boost::type_erasure::detail::rebind_placeholders<mpl_::arg<1>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >, mpl_::na, mpl_::na>’ ../boost/type_erasure/binding.hpp:163:13: instantiated from ‘boost::type_erasure::binding<Concept>::impl_type::impl_type(const boost::type_erasure::static_binding<Map>&) [with Map = boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<>, boost::type_erasure::typeid_<>, boost::type_erasure::ostreamable<> >]’ ../boost/type_erasure/binding.hpp:94:35: instantiated from ‘boost::type_erasure::binding<Concept>::binding(const boost::type_erasure::static_binding<Map>&) [with Map = boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<>, boost::type_erasure::typeid_<>, boost::type_erasure::ostreamable<> >]’ ../boost/type_erasure/any.hpp:167:22: instantiated from ‘boost::type_erasure::any<Concept, T>::any(const U&) [with U = char [4], Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<>, boost::type_erasure::typeid_<>, boost::type_erasure::ostreamable<> >, T = boost::type_erasure::_self]’ 01.cpp:11:49: instantiated from ‘display::display(const T&) [with T = char [4]]’ 01.cpp:26:28: instantiated from here ../boost/type_erasure/detail/rebind_placeholders.hpp:161:64: error: function returning an array In file included from ../../../1_50_0_beta1.cygwin/boost/preprocessor/iteration/detail/iter/forward1.hpp:67:0, from ../boost/type_erasure/detail/vtable.hpp:191, from ../boost/type_erasure/binding.hpp:28, from ../boost/type_erasure/any.hpp:39, from 01.cpp:2: ../boost/type_erasure/detail/vtable.hpp: In instantiation of ‘const boost::type_erasure::detail::vtable_storage4<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::type_erasure::destructible<boost::type_erasure::_self>, boost::type_erasure::typeid_<>, boost::type_erasure::detail::vtable_adapter<boost::type_erasure::ostreamable<>, void(std::basic_ostream<char>&, const boost::type_erasure::detail::storage&)> > boost::type_erasure::detail::vtable_init4<boost::type_erasure::detail::vtable_storage4<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::type_erasure::destructible<boost::type_erasure::_self>, boost::type_erasure::typeid_<>, boost::type_erasure::detail::vtable_adapter<boost::type_erasure::ostreamable<>, void(std::basic_ostream<char>&, const boost::type_erasure::detail::storage&)> >, boost::type_erasure::detail::rebind_placeholders<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >, boost::type_erasure::destructible<char [4]>, boost::type_erasure::typeid_<char [4]>, boost::type_erasure::detail::vtable_adapter<boost::type_erasure::ostreamable<std::basic_ostream<char>, char [4]>, void(std::basic_ostream<char>&, const boost::type_erasure::detail::storage&)> >::value’: ../boost/type_erasure/binding.hpp:163:13: instantiated from ‘boost::type_erasure::binding<Concept>::impl_type::impl_type(const boost::type_erasure::static_binding<Map>&) [with Map = boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<>, boost::type_erasure::typeid_<>, boost::type_erasure::ostreamable<> >]’ ../boost/type_erasure/binding.hpp:94:35: instantiated from ‘boost::type_erasure::binding<Concept>::binding(const boost::type_erasure::static_binding<Map>&) [with Map = boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<>, boost::type_erasure::typeid_<>, boost::type_erasure::ostreamable<> >]’ ../boost/type_erasure/any.hpp:167:22: instantiated from ‘boost::type_erasure::any<Concept, T>::any(const U&) [with U = char [4], Concept = boost::mpl::vector<boost::type_erasure::copy_constructible<>, boost::type_erasure::typeid_<>, boost::type_erasure::ostreamable<> >, T = boost::type_erasure::_self]’ 01.cpp:11:49: instantiated from ‘display::display(const T&) [with T = char [4]]’ 01.cpp:26:28: instantiated from here ../boost/type_erasure/detail/vtable.hpp:266:49: error: ‘value’ is not a member of ‘boost::type_erasure::detail::rebind_placeholders<boost::type_erasure::detail::vtable_adapter<boost::type_erasure::constructible<boost::type_erasure::_self(const boost::type_erasure::_self&)>, boost::type_erasure::detail::storage(const boost::type_erasure::detail::storage&)>, boost::mpl::map<boost::mpl::pair<boost::type_erasure::_self, char [4]>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >’
Thanks, --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/Formal-Review-Request-TypeErasure-tp46303... Sent from the Boost - Dev mailing list archive at Nabble.com.