Re: [Boost-users] [function][lambda] Create a boost function to a bind functor

From: Arnaldur Gylfason (arnaldur.gylfason_at_[hidden])
Date: 2006-10-19 07:54:47

a) You want to use _1 instead of _2
b) _1/_2 are in namespace boost::lambda
boost::function<float(float)> f = 
boost::lambda::bind(fx,boost::lambda::_1,2);

It is actually possible to use _2 but then the functor takes to args and 
ignores the first:
  boost::function<float(float,float)> f = 
boost::lambda::bind(fx,boost::lambda::_2,2);
  std::cout << f(100,3) << std::endl; // returns 5

cheers

Arnaldur

"Chris Weed" <chrisweed_at_[hidden]> 
Sent by: boost-users-bounces_at_[hidden]
19.10.2006 05:04
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Subject
[Boost-users] [function][lambda] Create a boost function to a bind functor

Hi,
I would like to create a boost::function to a lambda::bind functor such as

float fx(float a, float b) { return a+b; }

int main()
{
  boost::function<float(float)> f = boost::lambda::bind(fx,_2,2);
  std::cout << f(3) << std::endl;
  return 0;
}

I would expect this to bind 2 to the "b" argument of fx, and print "5".
Instead with msvc-8.0 I get a bunch or compile errors.
Any help would be greatly appreciated.
Chris
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