On Tue, Mar 23, 2010 at 10:02 AM, Stuart Dootson wrote:

Your code is fine when the bound thing is a method - you could use '&a' rather than 'boost::ref(a)' (a pointer to 'a' can be used for a method call in place of a reference to 'a')

However, for your 'double_it', I'd personally just write a function rather than define a struct with a method. Then, 'a' is not needed and the bind would be:

std::for_each( v.begin(), v.end(), boost::bind( &double_it, _1 ) );

It does indeed, thanks Stuart. I would of course lift the method from the class in real code, but this is just for exposition. In practise, as ever, there are additional constraints. - Rob. -- ACCU - Professionalism in programming - http://www.accu.org

On Tue, Mar 23, 2010 at 12:22 PM, Ovanes Markarian wrote:

Just in case you interested how to accomplish it with boost::lambda

#include "boost/lambda/lambda.hpp"

[...snip...]

Thanks Ovanes - I'm sure you will understand that my real code is a bit more complicated then doubling ints! Since both bind and lambda are pretty much superceded by phoenix now, perhaps you could also supply the phoenix version? - Rob.

Hi Ovanes, as far as i understand is phoenix an officially released boost lib. It has been reviewed.See http://lambda-the-ultimate.org/node/3012 and http://www.boost.org/doc/libs/1_42_0/libs/spirit/phoenix/doc/html/index.html Cheers, Kim Ovanes Markarian schrieb:

On Tue, Mar 23, 2010 at 2:19 PM, Robert Jones mailto:robertgbjones@gmail.com> wrote:

Thanks Ovanes - I'm sure you will understand that my real code is a bit more complicated then doubling ints! Since both bind and lambda are pretty much superceded by phoenix now, perhaps you could also supply the phoenix version?

As far as I know boost::phoenix is not an officially released boost lib. It is still part of boost::spirit library. There is no top level reference to it. So I would not consider it for now to be a replacement for bind and lambda. It might become, but don't rely on that. ;) Anyway here the rewritten example:

#include #include #include #include

#include <algorithm> #include <vector> #include <iterator> #include <iostream>

using namespace std; using namespace boost; using namespace boost::phoenix; using namespace boost::phoenix::arg_names; using namespace boost::phoenix::local_names;

namespace ph = boost::phoenix;

int main( ) { vector< int > v; // generate vector values int i=0; generate_n(back_inserter(v), 100, ++ph::ref(i));

//create the output iterator ostream_iterator<int> oiter(cout, ","); copy(v.begin(), v.end(), oiter); cout << endl;

// double each value in the vector for_each(v.begin(), v.end(), arg1*=2); copy(v.begin(), v.end(), oiter); cout << endl; }

Regards, Ovanes ------------------------------------------------------------------------

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Robert Jones wrote:

Thanks Ovanes - I'm sure you will understand that my real code is a bit more complicated then doubling ints! Since both bind and lambda are pretty much superceded by phoenix now, perhaps you could also supply the phoenix version?

- Rob.

Rob - I highly recommend moving to phoenix (despite comments made later in this thread). The library is extremely powerful and stable and has been conditionally accepted ( http://lists.boost.org/boost-announce/2008/10/0205.php ). The documentation is excellent and the support is speedy. I find phoenix constructs to be far more readable than boost.lambda resulting in overall improved understanding of the code's intent. Documentation can be found here: http://www.boost.org/doc/libs/1_42_0/libs/spirit/phoenix/doc/html/index.html Here is your example using phoenix ------------------- #include <iostream> #include <vector> #include int main() { using namespace boost::phoenix::arg_names; std::vector< int > vec; // fill the vector with something for( int i=0; i < 10; ++i ) { vec.push_back( i ); } // double them all std::for_each( vec.begin(), vec.end(), ( arg1 *= 2 ) ); // print them all out std::for_each( vec.begin(), vec.end(), ( std::cout << arg1 << " " ) ); std::cout << std::endl; return 0; } -------------------------------------------------------------- Hope this helps some - michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com