Re: [boost] [mpl] broken count and at metafunctions

From: David Abrahams (dave_at_[hidden])
Date: 2005-08-30 12:39:49

Matt Calabrese <rivorus_at_[hidden]> writes:

> As much as I love MPL, I have come across a couple more problems. First, on 
> MSVC++ 7.1, "count" returns 0 with maps, when there is an element in the map 
> with the specified key

That behavior matches the specified semantics of "count" perfectly:

http://www.boost.org/libs/mpl/doc/refmanual/count.html

Elements of a map are pairs.

>  (and probably on other compilers as well, though I 
> haven't checked the implementation). As well, while a 3-argument form of 
> "at" is described in documentation (where the third argument is the default 
> type returned by "at" if an element with the provided key does not exist in 
> the container), it does not appear to be implemented in 1.33.

You're right.  Aleksey?

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com