On 5/4/2010 3:49 PM, Daniel Walker wrote:
On Tue, May 4, 2010 at 1:49 PM, Peter Dimov<pdimov@pdimov.com> wrote:
Samuel Debionne:
Anyway, in my opinion, using bind/mem_fn/lambda with transform_iterator is a common use case. That would be great to have an option to add a default constructor in those libs... or is it to risky ?
The proper fix would be to make transform_iterator not require a default-constructible function object, by using boost::optional or an equivalent.
That's a great idea! I took a look at it, and the required changes seem to be minor. I made a ticket and attached a patch. https://svn.boost.org/trac/boost/ticket/4189 I ran Boost.Iterator regression tests with gcc 4.2 and it passed without error.
Daniel Walker
Maybe you should only conditionally wrap in a boost::optional, e.g., if has_trivial_constructor<F> is false (I don't think there's a standard is_default_constructible trait, right?). - Jeff