Re: [boost] [iterator] Proposal to add is_const_iterator trait

From: Andrey Semashev (andysem_at_[hidden])
Date: 2007-05-14 04:37:09

Hello shunsuke,

Monday, May 14, 2007, 3:31:29 AM, you wrote:

>> Here it is in the Vault:
>> 
>> http://tinyurl.com/2z56r2

> What does 'is_const' for iterators mean?

As the patched doc says, the trait returns true if the result of
iterator dereference is constant reference and false otherwise.

is_const_iterator< str::list< int >::const_iterator >::value == true
is_const_iterator< str::list< int >::iterator >::value == false

> The New Iterator concept defines Readable and Writable concept,
> but I don't know the definition of "constant" iterator.
> Well, I think 'iterator_reference<ItT>::type' can return a
> const-qualified type even if 'ItT' is Writable.

I don't see how would it be possible to write to a const.

-- 
Best regards,
 Andrey                            mailto:andysem_at_[hidden]