Re: [Boost-users] self-referential boost functions

28 Jun 2012

      Adam Crain  writes:
...
Inquiring  as to whether this is possible or if there is a better pattern
for simulating this behavior...
Is it possible for boost::function to be self referential? I.e. how do I
simulate behavior like the following:
typedef boost::function Func;
A function that does something mutable and then returns the next function
to be called or an empty function.
Boost.Function still requires static typing on the return type and that
type depends on some runtime variable, so you cannot statically type it.

What might work:

#include 
#include 

boost::any foo(int i) {
  if(i == 0) return boost::any();
  else return boost::functionboost::any(int)(&foo);
}

int main()
{
  boost::function< boost::any(int) > f = &foo;
  auto x = f(3);
  if(!x.empty()) {
     // maybe unsafe any cast?
    f = boost::any_cast >(x);
  } else {
    // hit end
  }

  return 0;
}

but I think that is possibly slower than you want.

HTH,
Philipp

Re: [Boost-users] self-referential boost functions

Philipp Moeller