[boost] Re: value_initialized, deep const, and template instantiation

From: Jim Apple (japple_at_[hidden])
Date: 2004-02-02 11:45:19

Fernando Cacciola wrote:
> A deep-const wrapper with preserving-const will be such that:
> 
> W<T> w;
> W<T> const wc;
> W<T const> cw;
> W<T const> const cwc;
> 
> test(w);
> test(wc);
> test(cw);
> test(cwc);
> 
> outputs:
> 
> mutable
> const
> const
> const
> 
> 
> value_initialized<> is a shallow-preserving-const wrapper:
> 
> 
> value_initialized<T> w;
> value_initialized<T> const wc;
> 
> value_initialized<T const> cw;
> value_initialized<T const> const cwc;
> 
> test(w);
> test(wc);
> test(cw);
> test(cwc);
> 
> outputs:
> 
> mutable
> mutable
> const
> const
> 
> Is this the behaviour you want?

On second thought, I think I like the first better - a user who has 
written const should expect const - no matter where it was written.

There are some notes on the isea of value wrapping, as well as a 
prototype for can_init at http://japple.freeshell.org/value_wrap.html

Jim