[boost] ReadableIteratorConcept and Borland BCB6

From: Alisdair Meredith (alisdair.meredith_at_[hidden])
Date: 2003-08-04 19:14:24

The concept checker ReadableIteratorConcept is causing several failures
for the new iterator adaptors under BCB6.

I have two possible patches, either of which solve the problem.

# if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT( 0x564) )
    typedef BOOST_DEDUCED_TYPENAME
boost::detail::iterator_traits<Iterator>::value_type value_type;
    typedef BOOST_DEDUCED_TYPENAME
boost::detail::iterator_traits<Iterator>::reference reference;
    typedef BOOST_DEDUCED_TYPENAME
boost::access_category<Iterator>::type access_category;
# else
    typedef BOOST_DEDUCED_TYPENAME
::boost::detail::iterator_traits<Iterator>::value_type value_type;
    typedef BOOST_DEDUCED_TYPENAME
::boost::detail::iterator_traits<Iterator>::reference reference;
    typedef BOOST_DEDUCED_TYPENAME
::boost::access_category<Iterator>::type access_category;
# endif

In this case, simply removing the global qualifier 'fixes' the parser.
Alternatively:

# if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT( 0x564) )
    typedef ::boost::detail::iterator_traits<Iterator> traits_type;
    typedef traits_type::value_type value_type;
    typedef traits_type::reference reference;
    typedef traits_type::type access_category;
# else
    typedef BOOST_DEDUCED_TYPENAME
::boost::detail::iterator_traits<Iterator>::value_type value_type;
    typedef BOOST_DEDUCED_TYPENAME
::boost::detail::iterator_traits<Iterator>::reference reference;
    typedef BOOST_DEDUCED_TYPENAME
::boost::access_category<Iterator>::type access_category;
# endif

By introducing an intermediate typedef, the global-namespace qualifier
is preserved.  I am not clear why there are no dependent typenames in
this second version, or if that is another BCB bug.

Likewise, I'm not clear which form of patch is to be preferred, so
present both <g>

[I suspect the same patch will be required for the Kylix compiler,
0x570, as well, but don't have that available for testing]

-- 
AlisdairM
Team Thai Kingdom