[boost] Iterator facade < operation?

From: Geoff Wedig (wedig_at_[hidden])
Date: 2006-06-29 08:43:52

I have a question I'm hoping someone can answer.  I've recently started 
using the iterator_facade class, and it's very useful, but it seems 
inefficient in some respects.  Specifically, the < operator.  According 
to the website docs, this uses the distance_to() function defined by the 
derived class.  That works fine for some iterators, but not others. 
Often, it's possible to have much more efficient operations than that. 
Take for example, some data structure of sorted strings.  It is not 
necessary to know how many elements are between two strings to know 
whether one is before the other.  Like 'use empty() rather than size() 
== 0' in Meyer's _Effective STL_, it would seem that a more efficient 
solution can be created in many cases.

So, is there a way to do this, to override iterator_facade's system, or 
am I missing something?  I have read most of the documentation, but that 
doesn't mean there isn't something I overlooked.

Thanks!

Geoff Wedig