Re: [Boost-users] Boost bind library question

15 Feb 2006

      Thanks. But I have the following compiler error. Thanks for any idea to fix it.

code:
#include "boost/lambda/bind.hpp"
#include "boost/lambda/lambda.hpp"

using namespace std;

using namespace boost::lambda;

transform(inputs.begin(), inputs.end(), bdl.begin(), _1 =
bind(new_ptr<Rect>()));

../TestBlockData.cpp: In member function 'void
TestBlockData::buildBlockDataList(std::vectorstd::string >&, BlockDataList&)':
../TestBlockData.cpp:119: error: '_1' was not declared in this scope
../TestBlockData.cpp:119: error: 'new_ptr' was not declared in this scope
../TestBlockData.cpp:119: error: expected primary-expression before '>' token
../TestBlockData.cpp:119: error: expected primary-expression before ')' token

On 2/14/06, Peter Dimov  wrote:
...
Meryl Silverburgh wrote:
...
How can I use boost:bind library to bind to constructor of a class.
Right now, I have code like this:
class build
{
public:
Rect* operator()(string& str)
 {
   return new Rect(str);
 }
};
void TestBlockData::buildRectList( vector<string>& inputs, RectList&
bdl) {
transform(inputs.begin(), inputs.end(), bdl.begin(), build());
}
I wonder if I can get rid of the whole "build class" by using
boost::bind library.
No, you can't; boost::bind can only adapt existing function objects into new
function objects, but as a general rule it can't create function objects
from scratch. The Lambda library has new_ptr<Rect>() that may work for you,
though:
http://www.boost.org/doc/html/lambda/le_in_details.html#lambda.construction_...
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