Re: [boost] [Bind] How do I get bind to deduce the return type of for_each?

17 Apr 2010

      Daniel Walker wrote:
...
On Sat, Apr 17, 2010 at 8:58 AM, Roland Bock <rbock@eudoxos.de> wrote:
...
Daniel Walker wrote:
...
On Sat, Apr 17, 2010 at 7:25 AM, Roland Bock <rbock@eudoxos.de> wrote:
...
for_each(vov.begin(), vov.end(),
      bind(for_each< vocType::iterator, function<void (myClass&)> >,
         bind<vocType::iterator>(&vocType::begin, _1),
         bind<vocType::iterator>(&vocType::end, _1),
         protect(bind(&myClass::func, _1))
         )
      );
Oh yeah, that's a good idea! Instantiate std::for_each with a void
boost::function! That's a portable solution as well, since bind and
function are available on practically any compiler, even ancient,
substandard ones.
Daniel Walker
Thanks :-)
Btw, could I do the same with tr1::bind? What would be the equivalent of
boost::protect?
Yeah, you can do the same thing in TR1. Instead of boost::protect, you
can just use tr1::function, again. :)
for_each(vov.begin(), vov.end(),
         bind(for_each< vocType::iterator, function<void (myClass&)> >,
            bind<vocType::iterator>(&vocType::begin, _1),
            bind<vocType::iterator>(&vocType::end, _1),
            function<void(myClass&)>(bind(&myClass::func, _1))
            )
         );
Actually, I once wrote a functional_cast (analogous to lexical_cast)
that did something like that. It's in vault.
Daniel Walker
OK, got it, the function object kind of digests the inner _1 before the 
outer bind can lay its fingers on it :-)

Just took a look at the polymorphic_function and functional_cast. I'll 
have to try and remember it, because I am sure I had use cases for that 
in the past (obviously solved them in another way). How would you apply 
them to the current topic?

Regards,

Roland