Re: [boost] [Range] Expected complexity constraints

From: David Abrahams (dave_at_[hidden])
Date: 2006-05-09 10:01:25

Thorsten Ottosen <thorsten.ottosen_at_[hidden]> writes:

> David Abrahams wrote:
>> Thorsten Ottosen <thorsten.ottosen_at_[hidden]> writes:
>
>>>The new version will feature special functions for generating ranges for
>>>the string library. We could probably wrap char* iterators in
>>>boost::string_iterator<char>. Are you sure we need the end iterator to 
>>>be a different type?
>> 
>> 
>> No, you don't, in fact.  Comparisons just get a little more expensive
>> than they'd need to be otherwise.
>
> You mean more expensive because you have to see which irerator that is 
> the valid one?

The checks are more complicated than that, but that's the general
idea.

> In that case it might be reasoable to always mandate the left argument 
> to be the valid iterator:

No, that violates EqualityComparable, not to mention every reasonable
person's expectations.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com