Re: [boost] RangeEx review

Subject: Re: [boost] RangeEx review
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2009-03-01 09:52:33

Phil Endecott wrote:

> - It would be good if the docs were explicit about this being a thin 
> wrapper around your existing std::sort, and identifying those algorithms 
> that are not so thin.

Actually, I believe sort(c) calls c.sort() if it exists.
So it's not just std::sort.

> You then have this example for sorting and removing duplicates:
> 
>   boost::erase( vec, boost::unique<boost::return_found_end>( 
> boost::sort(vec) ) );
> 
> Err... yuk.  Why can't I write:
> 
>   unique(vec);
> 
> Or maybe
> 
>   unique(sort(vec));
> 
> or
> 
>   sort(vec);
>   unique(vec);
> 
> My point is that std::unique only has its "move duplicates to the end" 
> behaviour because the conventional interface with a pair of iterators 
> doesn't let you change the size of the container.  Now that we have a 
> unique() that takes a container we don't need that restriction.

Not a container, a range.
You can't remove elements from a range, only move those to the end and 
change the end.

However, uniqued(vec) returns a new lazy range without duplicates (if 
the range is sorted), and unique_copy(vec) returns a new range without 
duplicates.