delegate_multicast.cpp

Shows how to use xtd::delegate class.

#define TRACE
#include <xtd/console>
#include <xtd/cdebug>
#include <xtd/ctrace>
#include <xtd/delegate>
#include <xtd/environment>
 
using namespace xtd;
 
using writer = delegate<void(const string& str)>;
 
void write_debug(const string& str) {
  cdebug << str << environment::new_line;
}
 
class tracer {
public:
  void write_trace(const string& str) {
    ctrace << str << environment::new_line;
  }
  
  void write_trace2(const string& str) {
    ctrace << "2 " << str << environment::new_line;
  }
};
 
auto main() -> int {
  auto write = writer {};
  
  write += [](const string & str)  {
    console::out << str << environment::new_line;
  };
  
  write += [](auto str)  {
    console::error << str << environment::new_line;
  };
  
  write += write_debug;
  write += {tracer(), &tracer::write_trace};
  
  auto t = tracer {};
  write += {t, &tracer::write_trace2}; // add
  write -= {t, &tracer::write_trace2}; // then remove
  
  struct writer {
    writer() = default;
    void operator()(const string& str) {
      console::write_line(str);
    }
  };
  
  write += writer();
  
  write("Value to write");
}
 
// This code produces the following output :
//
// Value to write
// Value to write
// Value to write
// Value to write
// Value to write