"Aleksey Gurtovoy"
Matt Calabrese wrote:
Okay, I decided before I continue with my other library, I'll fully implement rational_c properly (and possibly fixed_c), however, doing so without making the code horribly complex would require changes to the current definitions of pretty much all of the operations (plus, multiplies, etc. as well as the conditional operators). ^^^^^^^^^^^ I suppose you meant "comparison", here and below.
The problem is that those current functions take 5 parameters, making specialization nearly impossible for the rational and fixed templates as you'd have to account for when the 3rd, 4th, 5th, etc parameters are not passed (and so the default integral 0 is used). That can't be easily done (at least I don't see how) without having to specialize each condition separately (one for 3 rational types, one for 4 rational types, etc ). Moreso, this applies to the conditional operators as well, there is no easy way to account for using different types in multiplies IE multiplying a rational and integral together, or a fixed and rational, etc. Again, to account for these possibilities you'd have to make an incredibly large amount of specializations.
I have come up against the above problems. My solution was to create a metafunction like so: template< typename A, typename Op, // some type representing the op. //I actually use template<typename> class Op // with std::plus etc as the token typename B
struct binary_operation{ typedef ... result_type; // works with result_of }; notably compatible with mpl::plus (say); (This is actually my standalone impl of mpl ops. I dont use the extra params. OTOH My impl is easy to replace with official version namespace boost{namespace mpl{ template< typename A, typename B
struct plus
::result_type type; }; }}
Actually definition for my rational_c op integral_c and vice versa is then:
(Assuming binary_operation