Peter Dimov wrote:
When you construct a boost::function from &HandleClass::handle, what
actually gets stored is boost::mem_fn(&HandleClass::handle). See
http://www.boost.org/libs/mem_fn/
Even
std::vector< boost::shared_ptr<HandleClass> > listOfHcs;
will work.
Thanks Peter, makes sense after reading that documentation now.
I've actually got another question - I'd really prefer to replace
ReturnContainer with an output iterator type. So Extract would look
like this:
template
<
class InIterator,
class OutIterator,
>
void Extract(const InIterator & itBegin,
const InIterator & itEnd,
OutIterator & itOut,
boost::function1 f)
{
for (FwdIterator it = itBegin ;it != itEnd; ++it)
{
*itOut++ = f(*it);
}
};
And then you'd typically call Extract with an inserter:
Extract(listOfHcs.begin(), listOfHcs.end(),
back_inserter(needToFill), &HandleClass::handle);
But this doesn't compile because the inserters (at least on my platform)
don't define value_type. I'd prefer to take an iterator because it
gives greater flexibility (can use inserter, front_inserter or
back_inserter) and it more closely models the standard algorithms.
However, I need to know the return type of the function and I can't see
any way to get it without specifying it as a template parameter.
Actually, I think I could use the typedefs that are defined in the
inserters to retrieve the container, and then the value type, but this
then forces the client to use inserters.
Am I overlooking something here?
Cheers,
Matt
