Phil Endecott wrote: <snip>
reference. What I think I want to use is std::pair<KEY,VALUE&> i.e. the key is returned by value and only the value is returned by reference. But when I try this I get various cryptic errors about references to references and mpl things.
So, has anyone else tried to do something like this? I wonder if boost::reference could be part of the solution.
Thanks for any suggestions,
Phil.
I think your "references to references" problem could have to do with std::pair not being able to handle references "correctly" :( You might have to roll your own pair type that uses call_traits to avoid references to references... (I've had to do this myself) er's solution seems to do mostly what you want, except the value is wrapped in a reference_wrapper, which could be inconvenient. Also, probably want the mutable reference type to be a std::pair< const Key, ... >. - Jeff