[Boost-users] Re: Re: metaprogramming exercise 2-0

From: Ian McCulloch (ianmcc_at_[hidden])
Date: 2005-02-15 19:11:24

Chris Goller wrote:

> David-
> 
> First, thanks for the response.  BTW, I really like the book.
> 
> Okay, I understand what you are saying about add_const and how it works.
> 
> My next question is why was it implemented in that way?  In other words,
> was there a specific reason not to make a special case
> for references such that add_const<int&> would be int const &?

FWIW, you will soon be able to get that effect without a metafunction.  
from http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#106
[example]
int i;
typedef int& RI;
RI& r = i;          // r has the type int&
const RI& r = i;    // r has the type const int&
[/example]

I'm not sure I like it, because a 'RI const' is 'int&', but a reference to a
'RI const' is 'int const&'.  But maybe its useful that way.

Cheers,
Ian McCulloch