Martin Bonner wrote:
Manfred Doudar wrote:
/* Now, how do I get T out when Rank == 1, ... compiler complains about seeing a MyArray/blitz::Array of <T, Rank = 0> (, which is not defined for blitz Arrays) */ template <typename T, int Rank> typename boost::mpl::if_ < typename boost::mpl::equal_to < boost::mpl::int_<Rank> , boost::mpl::int_<1> >::type , T , blitz::Array<T,
boost::mpl::int_<Rank>::prior::value>
^ Oops typo, should be: MyArray<T,
boost::mpl::int_<Rank>::prior::value>
... but nonetheless, the problem remains ...
>::type MyArray<T, Rank> :: operator[] (const int& index) throw(); { // Slicing
How about a helper traits class?
template <typename T, int Rank> struct SliceType { typedef typename MyArray<T, Rank-1> type; };
template <typename T> struct SliceType<T,1> { typedef T type; };
template <typename T, int Rank> typename SliceType<T,Rank>::type MyArray<T,Rank> :: operator[] (const int& index) throw();
Now I'm sure that ought to have worked (even after modifying as you've suggested) ... but the problem _still persists_ , not per say on the definition of return type, but seemingly inside the _template body_, where the *static_cast* is done to map the final result accordingly ... please see below: Partial Code Listing: -------------------- template <typename T, int Rank> typename SliceType<T, boost::mpl::int_<Rank>::value>::type MyArray<T, Rank> :: operator[] (const int& index) throw() { // Slicing blitz::TinyVector<boost::variant<blitz::Range, blitz::nilArraySection>, 2> plist; this->getParamList(plist); return // *********************************************** // ** Complier complains about this cast seeing // ** MyArray/blitz::Array <T, 0> // ** when Rank == 1 // ** ... see partial compiler error msg below // *********************************************** static_cast< typename SliceType<T, // ** [ Line 697 ] ** boost::mpl::int_<Rank>::value>::type > ( ((* static_cast<const blitz::Array<T, boost::mpl::int_<Rank>::value> *> (this)) /* the parameter list */ (index, *boost::get< typename boost::mpl::if_< typename boost::mpl::less< boost::mpl::int_<1> , boost::mpl::int_<Rank> >::type , blitz::Range , blitz::nilArraySection >::type > (&plist(boost::mpl::if_< typename boost::mpl::less< boost::mpl::int_<1> , boost::mpl::int_<Rank> >::type , boost::mpl::int_<0> , boost::mpl::int_<1> >::type::value ) ) /* , ... we can extend the parameter list with Boost.PP */ ); } (Partial) Compiler Error Message: --------------------------------- In member function `SliceType<T, boost::mpl::int_<Rank>::value>::type MyArray<T, Rank>::operator[](const S&) [with S = int, T = float, int Rank = 1]': arr.cc:197: instantiated from here arr.cc:697: invalid static_cast from type `blitz::Array<float, 0>' to type ` float' <snip .. more messages> /usr/local/include/blitz/array/storage.h:60: no match for call to `( blitz::TinyVector<int, 0>) (int&)' <snip .. more messages> Somewhere in main(..) --------------------- blitz::Array<float, 2> b2(2, 2); // 2D array (2 x 2) b2 = 1.1, -2.2, -9.9, 8.8; MyArray<float, 2> a2(b2); std::cout << a2[1] ; // this works std::cout << a2[1][1] ; // ** [Line 197] ** the problem is here Any and All help is Appreciated, I know it's got to be something simple, I just can't see it yet. With Thanks, -- Manfred Doudar MetOcean Engineers www.metoceanengineers.com