Re: [Boost-users] Signals, Format and Bind

8 Dec 2006


      Memfis wrote:
...
Peter Dimov wrote:
...
...
I am trying to achieve this with format and bind, but without much
 luck. What I came up with is the following:
source.connect(bind(ref(target),
    bind(&format::str,
        bind(&format::operator%,
            format("the value is %1"), _1)));
Your format string throws an exception for me. Perhaps you need to
use %1%?
Argh. I made a typo while editing the post. I use %1% of course. But
it still doesn't work.
The following works for me. I had to disambiguate format::operator% because 
it's a template, though, it couldn't compile as is. It would've been nice if 
format provided operator() as an alias so it could be bound.

#include <iostream>
#include <boost/format.hpp>
#include <boost/bind.hpp>
#include <boost/signal.hpp>

void f( std::string str )
{
    std::cout << str << std::endl;
}

int main()
{
    using namespace boost;

    signal< void( std::string ) > target;

    target.connect( &f );

    format& (format::*pmf)( int const & ) = &format::operator%;

    signal< void( int ) > source;

    source.connect(

        bind( ref( target ),
            bind( &format::str,
                bind( pmf, format( "the value is %1%" ), _1 )
            )
        )

    );

    source( 12345 );
}