Re: [Boost-users] [lambda] Understanding placeholders

15 Jan 2009


      AMDG

Robert Jones wrote:
...
Why is this wrong?
#include "boost/lambda/lambda.hpp"
#include "boost/lambda/bind.hpp"
#include <iostream>
int main( )
{
  using namespace boost :: lambda;
  int i = 2, j = 3;
  bind( bind( protect( _1 = _2 ), _2, _1 ), _1, _2 )( i, j );
  std :: cout << "i = " << i << ", j = " << j << "\n";
}
Evaluation:

  bind( bind( protect( _1 = _2 ), _2, _1 ), _1, _2 )( i, j );
  bind( _1 = _2, j, i )(i, j);
  (i = j)(j, i );

In Christ,
Steven Watanabe