On Tue, Nov 29, 2011 at 1:30 PM, Daniel James <dnljms@gmail.com> wrote:
On 29 November 2011 13:09, Robert Jones <robertgbjones@gmail.com> wrote:
In this code (fabricated) sequence, ages_by_bind compiles, but ages_by_lambda does not.
I believe this is because the lambda version does not publish result_type to its resultant functors, since the increased generality of lambda makes this difficult or impossible to do.
Is there any way I can get round this, as it currently makes the lambda/transformed combination completely unusable AFAICS.
Have you tried using Phoenix? It has better support for result_type.
I have now, precisely because I'd understood it had better support as you said. Like this, perhaps someone could tell me if this is fine on 1.44/1.47 too! Thx, - Rob. #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/home/phoenix/bind.hpp> #include <boost/spirit/home/phoenix/core/argument.hpp> std::vector<int> ages_by_phoenix( const std::map<std::string, int> & people ) { namespace ph = boost::phoenix; namespace arg = boost::phoenix::arg_names; using boost::adaptors::transformed; std::vector<int> result; boost::range::push_back( result, people | transformed( ph::bind( & std::map<std::string, int>::value_type::second, arg::_1 ) ) ); return result; }