Re: [boost] [review][mp11] Formal review of Mp11

Vinnie Falco wrote:

* The documentation states: "mp_if_c is an alias for T. mp_if_c is an alias for E. Otherwise, the result is a substitution failure."

Should that read "mp_if_c"? If not, why?

No. The idea here is that mp_if_c can be used in two ways. One is mp_if_c, which gives either T or E depending on Cond. The other is mp_if_c, which is the same as std::enable_if_t - gives T when Cond, otherwise a substitution failure. So mp_if_c is T mp_if_c is T mp_if_c is E Aliases can't be specialized, so it's not possible to implement just the above, which is why it takes a parameter pack for E... and does mp_if_c is T mp_if_c is E which for the three cases we're interested in gives the results we need.