Hi Dave, The documentation at http://www.boost.org/libs/mpl/doc/refmanual/vector.html says for pop_front<v>::type: A new vector of following elements: [next< begin<v>::type>::type,end<v>::type) It suggests (in my opinion) that the result_type of pop_front is a vector. Should the documentation be clearer about this? Thanks, Karl On Thursday 22 September 2005 19:31, David Abrahams wrote:

Karl Meerbergen writes:

...

Dear boost users,

I have a question regarding mpl.

Consider the following piece of code:

typedef boost::mpl::vector v_i_d_t ; typedef boost::mpl::pop_front::type v_d_t ;

Is v_d_t equal to boost::mpl::vector<double> ? I do not have the impression.

boost::mpl::equal::value is true but boost::is_same::value may be false.

HTH,

Karl Meerbergen writes:

Hi Dave,

The documentation at http://www.boost.org/libs/mpl/doc/refmanual/vector.html says for pop_front<v>::type: A new vector of following elements: [next< begin<v>::type>::type,end<v>::type)

It suggests (in my opinion) that the result_type of pop_front is a vector.

It is a vector. A vector does not necessarily have to be a specialization of mpl::vector. Hmm, I think in this case "vector" should not be set in code font, though. Aleksey?

Should the documentation be clearer about this?

That's what the use of "concept-identical" in the reference manual is intended to convey. http://www.boost.org/libs/mpl/doc/refmanual/extensible-sequence.html Do you have a specific suggestion that should be used to clarify the docs? BTW, this point is also very clearly explained in "C++ Template Metaprogramming," in case you haven't read it. -- Dave Abrahams Boost Consulting www.boost-consulting.com

Karl Meerbergen writes:

Perhaps it could be mentioned that pop_front, pop_back, insert etc return a VariadicSequence, (which it is I suppose?). For me it would be clear it is not an mpl::vector type.

Well, it is concept-identical to a vector, so that doesn't add any new information.

I am not enough familiar with the mpl concepts to be sure that my suggestion is correct.

It's technically correct, but I don't think it would help anyone else. -- Dave Abrahams Boost Consulting www.boost-consulting.com