------- Additional Comments From sven at clio dot in-berlin dot de 2005-05-15
17:58 -------
This is the last try. First I wonder who has invented the strange syntax for
defining template member classes outside. C++ is still an imperative
programming language, not a functional. A straightforward syntax would be
template<typename _T>
struct heap<_T>::template<>
struct iterator: wrapper<typename heap<_T>::pointer> {};
But that is not Your concern (unless You are a member of the standardization
comitee). The errors I get now is:
test.cpp:32: error: aggregate `heap<int>::iterator<container::pointer> p' has
incomplete type and cannot be defined
test.cpp:32: error: storage size of `p' isn't known
Simply untrue.
If You replace line 29 with
struct heap<_T>::iterator<container::pointer>:
the errors are
test.cpp:29: error: template parameters not used in partial specialization:
test.cpp:29: error: `_T'
test.cpp:32: error: aggregate `heap<int>::iterator<container::pointer> p' has
incomplete type and cannot be defined
test.cpp:32: error: storage size of `p' isn't known
Anyway, the workaround posted earlier is much more comprehensive and easier to
read.
--- test.cpp
template<typename _T>
class wrapper
{
public:
wrapper(): _M_t() {}
wrapper(_T t): _M_t(t) {}
operator _T& () { return _M_t; }
private:
_T _M_t;
};
struct container
{
struct pointer {};
struct forward {};
struct backward {};
struct bidirectional {};
struct randomaccess {};
};
template<typename _T>
struct heap: container
{
typedef _T value_type;
template<typename _U> struct iterator;
};
template<> template<typename _T>
struct heap<_T>::iterator<typename heap<_T>::pointer>: // line 29
wrapper<typename heap<_T>::value_type *> {};
heap<int>::iterator<heap<int>::pointer> p;
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21543
