[boost] Re: Re: typeof: lvalue preserving

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2004-07-24 06:29:45

"Andy Little" <andy_at_[hidden]> wrote

> I will definitely aim to try it out in depth with my physical quantities
> library in VC7.1, hopefully within couple of weeks. Two obvious points to
> look for are
>
> 1) How easy is it for the user (ie me) to implement in practise.

Quite easy, IMO, and totaly non-intruisive.  You just have to tell the
typeof library about your types (name) and templates (name and the number of
parameters).  For the example with Lambada, that I provided before, this
would mean to write something like following:

BOOST_TYPEOF_REGISTER_TEMPLATE(boost::tuples::tuple, 2);
BOOST_TYPEOF_REGISTER_TEMPLATE(boost::lambda::lambda_functor, 1);
BOOST_TYPEOF_REGISTER_TEMPLATE(boost::lambda::lambda_functor_base, 2);
BOOST_TYPEOF_REGISTER_TEMPLATE(boost::lambda::relational_action, 1);
BOOST_TYPEOF_REGISTER_TEMPLATE(boost::lambda::logical_action, 1);
BOOST_TYPEOF_REGISTER_TEMPLATE(boost::lambda::other_action, 1);
BOOST_TYPEOF_REGISTER_TYPE(boost::lambda::greater_action);
BOOST_TYPEOF_REGISTER_TYPE(boost::lambda::less_action);
BOOST_TYPEOF_REGISTER_TYPE(boost::lambda::and_action);
BOOST_TYPEOF_REGISTER_TYPE(boost::lambda::placeholder<1>);
BOOST_TYPEOF_REGISTER_TYPE(boost::lambda::placeholder<2>);

After this you can use any combination of registered types/templates (and
primitive types, which are registered by the typeof library) -- the system
will be able to process it.

> 2) How much does it affect compile times.

Well, it does affect it.  On my 1.5GHZ PC, VC7.1, it takes 2 to 3 sec to
process the above-mentioned Lambda expression (I do not count the time
needed to #include my stuff, as well libraries that I use -- in VC7.1 you
can almost eliminate it by using pre-compiled headers).

> Because my library is not boosted it will be a more interesting test.

OK, but I assure you that there is nothing in the typeof system that makes
it easier to use with boostified libraries.

Regards,
Arkadiy