[boost] Re: Exception safety guarantie

From: David B. Held (dheld_at_[hidden])
Date: 2004-07-18 00:16:49

David Abrahams wrote:
> [...]
> Very bad idea.  There's no reason that the algorithm should give up
> the basic guarantee in that case.  Consider:
> 
>     template <class InputIterator>
>     std::vector::assign(InputIterator,InputIterator)
> 
> That really gives the basic guarantee with no hidden assumptions.

It assumes that there are no invariants that require, for instance,
that all the input is consumed.

> [...]
> In case you think this is an "evil glossing over of detail",

I wouldn't call it "evil"...

> there are actually lots of these assumptions lurking in standard
 > requirements, but they still work very well.  For example, if
 > incrementing InputIterator actually had the side-effect of modifying
 > the vector, how well do you think std::vector::assign would work?
 > How understandable do you think the specification would be if all
 > these kinds of details were actually spelled out?

...but I guess it's the difference between a theorist and an engineer.
As a little of both, I would like to simultaneously argue for rigor
and pragmatism. ;)

Dave