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

Subject: Re: [Boost-users] [lambda] Understanding placeholders
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-01-15 12:22:28

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