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

From: Andy Little (andy_at_[hidden])
Date: 2005-12-21 19:17:45

"Arkadiy Vertleyb"  wrote ...

> I will try to implement such registrations for mpl::vector[n], as an
> example.  However, I think it's ultimately up to the library authors do
> decide whether or not to make their libraries typeof-enabled (I would be
> happy to provide any help on the subject).

Types are an implementation detail in mpl , so as I understand it, even if  I as
a user ,currently register the actual types of the result, then there is no
guarantee that they will remain the same in the next version of the library,
which makes theoretically  for high maintenance unless the library author deals
with it instead. I guess its not to bad in practise, but means my quantity
library is relying on artefacts of the implementation if I use mpl, and I dont
really like that :-(

BTW... I guess it might be glaringly obvious, but it might be worth mentioning
in the documentation that when the inbuilt error output fails regarding lack of
type registration( When pages and pages of template parameters appear) , that
using typeid(T).name() will provide useful information on the make-up of a
particular type, an alternative aid to finding the particular types that havent
been registered. Maybe its too obvious too mention but I forgot about it
recently. After I started using this approach it dramatically speeded up my
debugging.

Finally thanks again for the Typeof library. Despite all my moaning, I think its
a great addition to boost :-)

regards
Andy Little