[Boost-users] Command pattern Was: [bind] Pointer to functions as template parameters

From: Simon Carter (simon.carter_at_[hidden])
Date: 2005-09-15 08:47:41

Simon Buchan <simon <at> hand-multimedia.co.nz> writes:

> 
> Bruno Martínez wrote:
> > Hi.
> > 
> > When using pointers to functions with bind, the particular function  
> > doesn't play a part in the return value's type of bind.  That is
> > 
> > void func1();
> > void func2();
> > 
> > typeid(boost::bind(&func1)) == typeid(boost::bind(&func1)) // this is true
> > 
> > I need the types to be different to store bind objects with the  
> > serialization library.  The C++ Templates book proposes an adaptor that  
> > takes the pointer to function as a template parameter.  However, this  
> > adaptor is particular to a given signature, and I don't know how to  
> > rewrite it more generally.  Is this possible?  Can I more easily make  
> > boost::bind do what I want?
> > 
> > Bruno
> You may be making more work for yourself than you need to, why
> do you need to serialize bind objects? I haven't used the
> serialization lib, but a quick look-through doesn't really bring
> any times to mind where I would want to serialize a boost::bind
> functor!
> 

I would like to do the same thing - boost::bind can be used to bind an instance
of an object, a member function pointer _and_ any parameters required by that
function.

This leads to a really useful implementation of the command pattern - you can
build a list of these functors which constitute a composite command, and to
serialise the whole lot - or part - would be invaluable in all sorts of
situations including tracking how much of the composite command had actually
been implemented.

Maybe I should generalise and boostify my implementation. Any interest?

S