David Abrahams writes:

"Lemings, Eric B. \(Contr\)" writes:

...

Where is at' defined in MPL? I can't find the header file that defines it.

I don't think it is defined in MPL. After all, boost::mpl::at has only two template parameters. I think you've uncovered a documentation bug. Aleksey?

I'd rather say it's an oversight in the code that needs to be fixed. The version with a default is time-proven to be an essential part of a user-friendly associative sequence interface. -- Aleksey Gurtovoy MetaCommunications Engineering