[Boost-users] Re: Mpl problem

"Arkadiy Vertleyb" writes:

"Delfin Rojas" wrote

...

I am having a problem with the mpl library and I wonder if someone could help me with it. Basically I am trying to get a joint_view of two mpl::vector types and I get an error message on mpl/clear.hpp saying

clear_traits< Tag > ::template algorithm< Sequence >

base class undefined.

I tried including several of the mpl hpp files, the ones that seemed could have something to do with this problem but that didn't help. I also get a similar problem trying to use mpl::push_back. In this case I get

push_back_traits< Tag > ::template algorithm< Sequence,T >

Base class undefined.

On the other hand mpl::push_front and mpl::insert compile beautifully.

The error messages you are getting basically say:

"This algorithm is undefined for this type of sequence."

Exactly. Like all other views, joint_view is not extensible. How could you push_back onto a view, anyway? push_back is supposed to return the same "kind" of sequence as its input, but you can't add an element to a joint_view. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com