[Boost-users] Re: composition and arguement binding: what to use: boost::bind vsboost::mpl vs boost::lambda

Stuart Dootson writes:

On Tue, 15 Mar 2005 11:56:31 -0500, Robert Mathews wrote:

...

I've become rather confused about the exact relationship between these libraries. In particular, boost::mpl seems to contain placeholders and lambda templates just like boost::bind and boost::lambda.

That leds me to wonder if there would be any point to using boost::bind or boost::lambda if you are using boost::mpl? In fact, if boost::mpl is a functional superset of the other two libraries, why not drop those libraries from boost altogether and eliminate the confusion?

Rob.

boost::mpl performs binding of meta-functions (i.e. binding within the compile-time domain), whereas bind and lambda perform binding of functions and function objects (i.e. binding within the run-time domain).

As far as I can see, Boost.Bind is effectively a subset of Boost.Lambda (I may well be wrong, though!). However, if you're using an older compiler (such as MSVC6), then using Boost.Lambda can be problematic, whereas Boost.Bind works fine.

And unless Boost.Lambda has been updated since I looked, there are some nice things that Boost.Bind handles automatically, like calling through smart pointers, that aren't quite so easy with Boost.Lambda. -- Dave Abrahams Boost Consulting www.boost-consulting.com