Dave Abrahams wrote:
Side note:
* There is also a fully automatic approach (i.e. when an rvalue range is adapted, `moved_range` is automatically used without piping it to `moved` adaptor). But this approach incurs unnecessary overhead when passing them to functions, because function arguments do not have the lifetime issue and we don't need to use `moved_range`. So I prefer the "manual" approach.
Could you illustrate this with an example? I'd like to understand the trade-off you're making.
Here is an example of the manual approach: template <typename Range> void f(Range&&); // No lifetime problem. f(std::string("Hello world!") | reversed); // `moved` is not necessary. f(std::string("Hello world!") | moved | reversed); In the automatic approach, `std::string("Hello world!") | reversed` returns `moved_range<std::string, boost::fusion::vector<reverse_forwarder> >`. So there is unavoidable overhead (i.e. moving a temporary container into range adaptors) in `f(std::string("Hello world!") | reversed);`. Regards, Michel