Re: [boost] Typeofand mpl(was Interest indimension/unit-checkinglibrary?)

From: Andy Little (andy_at_[hidden])
Date: 2005-12-24 05:02:57

"Arkadiy Vertleyb" wrote in message
> "Andy Little" wrote
>
>> Small sample enclosed.( Let me know if you want a bigger portion.) .
>
> c:\boost\boost_1_33_0\boost\typeof\encode_decode.hpp(24) : error C2504:
> 'boost::type_of::`anonymous-namespace'::encode_type_impl<V,Type_Not_Register
> ed_With_Typeof_System>' : base class undefined
>        with
>        [
>            V=[...],
>            Type_Not_Registered_With_Typeof_System=boost::mpl::vector6<...
>            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> This complain about mpl::vector6 not registered.

That is true , but the error message is not correct. In  my typeof registration 
I have registered vector6 with Typeof. This is not the registration that is 
lacking. I guess that VC7.1 goes off the rails somewhere close by but, fact is 
that the error message is pointing to the wrong place on this occasion.

FWIW I dont really see this as a problem for Typeof, which does provide good 
diagnostics in simpler cases. I am just pointing out that, when the 
error-checking is not helping as in the above case, then an alternative approach 
is to use Typeid to find out what types your type is made up of.  This is 
particularly useful with e.g. mpl both because types are likely to be 
complicated and because its not always possible to know the exact mpl type your 
type is made of.

regards
Andy little