Re: [Boost-users] [phoenix][units] make boost.phoenix play well with boost.units

6 Jun 2010

      On Jun 4, 5:55 pm, alfC  wrote:
...
...
The type-deduction respects references. Phoenix2 passes in references.
The code should be:
...
   template<> //in general template
   struct result_of_multipliessi::length&, quantitysi::length&>
   {
       typedef quantitysi::area type;
   };
Actually (unfortunately) it seems that all 4 combinations of reference/
no reference are needed.
This is the only way I managed to make these expression work with type
deduction:
arg1*arg1
(arg1*arg1)*arg1
arg1*(arg1*arg1)
(arg1*arg1)*(arg1*arg1)

So, I have to implement this kind of macro sorcery to bridge
Boost.Units and Boost.Phoenix. Not sure if I will find another bump in
the road:

namespace boost{
namespace phoenix{
using namespace boost::units;
#define RESULT_OF_GEN( PhoenixnamE, UnitsnamE, RefQ1, RefQ2 ) \
	template \
	struct result_of_##PhoenixnamE  RefQ1,
quantity RefQ2>{ \
		typedef typename
UnitsnamE##_typeof_helper&,quantity&
...
::type type; \
   };
   RESULT_OF_GEN(multiplies, multiply, &,  )
   RESULT_OF_GEN(multiplies, multiply, &, &)
   RESULT_OF_GEN(multiplies, multiply,  ,  )
   RESULT_OF_GEN(multiplies, multiply,  , &)
   RESULT_OF_GEN(divides   , divide  , &,  )
   RESULT_OF_GEN(divides   , divide  , &, &)
   RESULT_OF_GEN(divides   , divide  ,  ,  )
   RESULT_OF_GEN(divides   , divide  ,  , &)
#undef RESULT_OF_GEN
}}