Re: [Boost-users] [Bind] How to create a functor which returns one ofits arguments?

Why would you do this? (I mean the standard unary functor). Thanks Andrew On Wed, Dec 9, 2009 at 11:10 AM, Peter Dimov wrote:

Vadim Guchenko wrote:

...

Hello, All!

Is there a simple way to create a functor that returns one of its arguments _1, _2, ...? Does standard unary functor exist, which simply returns its argument unchanged? I.e.:

template<typename T> struct arg: public std::unary_function {       T operator()(const T &x) const { return x; } };

It's not part of the current standard, but many implementations provide std::identity as an extension. (It will be standard in C++0x.) _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

-- ___________________________________________ Andrew J. P. Maclean Centre for Autonomous Systems The Rose Street Building J04 The University of Sydney 2006 NSW AUSTRALIA Ph: +61 2 9351 3283 Fax: +61 2 9351 7474 URL: http://www.acfr.usyd.edu.au/ ___________________________________________