I have the following iterator_adaptor type:
template< class NODE >
struct node_iterator: public boost::iterator_adaptor<
node_iterator<NODE>, // Derived
NODE*, // Base
typename NODE::value_type // Value
>
{
typename NODE::value_type dereference() const {
return this->base_reference()->data();
}
};
// and later:
typedef detail::node_iterator iterator;
typedef detail::node_iterator<const node_type> const_iterator;
This throws up the issue that in const_iterator, Value is not const,
producing the following error:
/usr/include/boost/iterator/iterator_facade.hpp:517:32: error:
invalid initialization of non-const reference of type
‘container::detail::node_iterator::reference {aka long unsigned int&}’ from an rvalue of
type ‘container::detail::node<long unsigned int>::value_type {aka long
unsigned int}’
I could do some type traits magic with is_same, is_const and add_const
to add the constness to Value if present on NODE, but is this the
right way to do it?
I've also thought about indirect_iterator - but adding operator*() to
the node type seems not quite right. Perhaps transform_iterator...or
is there some different method that might be more suitable?
TIA,
--rob
--
Rob Desbois
Blog: http://theotherbranch.wordpress.com/
"I disapprove of what you say, but I’ll defend to the death your right
to say it", Voltaire
