RE: [boost] Submission: typelist

From: Aleksey Gurtovoy (alexy_at_[hidden])
Date: 2001-11-27 10:53:15

Hamish Mackenzie wrote:
> On Tue, 2001-11-27 at 03:09, Aleksey Gurtovoy wrote:
> > It is! For instance, consider stuffing a type_list by a 
> > dozen of integer values (boost::mpl has value_list for 
> > that, but let's ignore it for the sake of the example); 
> > with the names you propose, it will be 
> > something like this:
> > 
> >     typedef type_list<
> >         let_value_be<int,1>, let_value_be<int,7>, 
> let_value_be<int,5>,
> >         let_value_be<int,2>, let_value_be<int,4>, 
> let_value_be<int,8>, 
> >         let_value_be<int,9>, let_value_be<int,2>, 
> let_value_be<int,0>,
> >         let_value_be<int,3>, let_value_be<int,9>, 
> let_value_be<int,1>
> >         > values;
> > 
> > IMO, there is too much visual clutter here, especially if 
> > you consider how little information the above 
> > declaration carries. Or, for example, here is a
> > compile-time 'for' loop:
> 
> I think we can solve this.  See Emily's post and my follow up.

As I said above, boost::mpl DOES have 'value_list' template, so one can
write

    typedef mpl::value_list<1,7,5,2,4,8,9,2,0,3,9,1> values;

The above was just an example how cumbersome things can get if your
'int_t<N>' is spelled 'let_value_be<int,N>'. This does matter - consider,
for example, creating a heterogeneous list of int_t's and "ordinary" types.

Aleksey