Hello Christian, Christian Holmquist wrote:
Hello, I decided to mail you directly not to spam the boost dev-list with minor questions, hope it's ok.
Sure, but I think we're not spamming ;-). To the contrary, it's valuable to discuss this stuff on-list (forwarding to boost.devel -- hoping it's OK), because ...
My question is how to disable the call operators with fewer arguments than specified by Sequence, generated by unfused_typed<F, Sequence>. Before the switch to boost::result_of one could specialize the result struct to only handle the expected Sequence type, thus disabling unwanted operators. I'm not familiar with boost::result_of to describe this however.
... I removed that kind of control over the overload sets of the Fusion functional adapters (you can't pass emptiness through result_of), but I'm not really happy about it. <snip code>
Any ideas? Currently I think it might be best to re-add that mechanism for the 'unfused_*' adapters, either by checking nested 'result' of the target function for emptiness (exploiting SFINAE where applicable) or by introducing a special type (e.g. 'fusion::undefined_function'), that when returned from 'result_of' disables the overload...
Thoughts anyone? Regards, Tobias