E. Gladyshev wrote:
1. I think that one of the important applications of the library is creating named parameters wrapper around legacy C interfaces with a bunch of parameters. It seems to me that named parameters functors are an elegant way to do it without macros. I personally belong to a large group of developers who don't favor macros unless there are really necessary. Please I don't mean to get into a discussion about macros in general.
I don't remember there being a requirement to use macros on this named_params library. And I showed how to do exactly that, wrap C style function, in my example (in my review) without macros.
Here is an example with class members. I think that it is much more fun than macros. :)
struct widget { //define a named parameters functor typedef ttl::func::named_params_function< int //the function returns 'int' ( //'argument name', 'argument type' title, const char* , style, ttl::func::numeric_argument<int, 45> //the default is 45 ) > create_functor;
// widget() { //initialize the functor with create_impl create = boost::bind( &widget::create_impl, this, _1, _2 ); }
create_functor create;
private: int create_impl( const char* title, int style ); };
main() { widget w;
w.create( w.create.arg<title>("my widget") );
return 0;
}
It may be "fun", but the overhead is overwhelming. I find this alternative more appealing... namespace { boost::keyword<struct title_t> title; boost::keyword<struct style_t> style; } struct widget { widget() { } int create( const char * title, int style ); template<class Params> inline int create(const Params & params) { return create(params[title], params[style | int(45)); } }; int main() { widget w; w.create((title = "my widget)); return 0; } Especially considering that the overhead is *zero* with release optimizations. And you can also do the more normal construction by adding: template<class Params> widget(const Params& params) { create(params[title], params[style | int(45)); } I fail to see how the functor gives you anything here. Perhaps you need a better counter example? -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com - 102708583/icq