David Abrahams wrote:
Ion Gaztañaga <igaztanaga@gmail.com> writes:
I would now propose something like:
template <class T, class Difference = std::ptrdiff_t> class repeat_read_iterator : public boost::iterator_facade < repeat_read_iterator<T, Difference> , const T , boost::random_access_traversal_tag , const T & , Difference>
so dereferencing "repeat_read_iterator<T>" would return const T & with random_access_traversal capability to be able move fast inside that "virtual read-only array". Am I missing something?
Only that the library will assign the wrong category unless you do something to prevent it.
Do you see this read only repeated sequence simulation useful to include it the iterator library?
Sure. But useful enough? That I do not know.
I think the iterator is related to Boost.MPL's 'single_view'. In the context of iterators, it is maybe 'single_range', which is the iterator pair of (&x, &x + 1). I said the iterator could be more generalized by changing the parameter to a range: if (equals(make_repeat_range(make_single_range('x'), 6), std::string("xxxxxx"))) {... if (equals(make_repeat_range(std::string("xxx"), 2), std::string("xxxxxx"))) {... Using nicer syntax: if (equals( std::string("xxx")|repeated(2)|jointed(std::string("yy")), std::string("xxxxxxyy") ) {... That iterator seems to raise yet another regex/xpressive? :-) (though I'm not sure it is legal.) -- Shunsuke Sogame