container stuff

[Michel Fortin]

On 2010-05-25 18:27:32 -0400, Andrei Alexandrescu 
<SeeWebsiteForEmail at erdani.org> said:

> There are a bunch of "soft" primitives. Those are meant to put a stop 
> to the iterator invalidation problems experienced in the STL. The 
> container implementor may alias softXyz to xyz if she knows the 
> operation won't mess the ranges currently iterating the container 
> (which is the case for most node-based containers). I haven't yet 
> discussed subtler cases in which a range starts with a removed element 
> etc., but I plan to.

Looks good, but I think something is missing. While I agree with the 
idea of having distinguishable "soft" operations, to pass it to other 
functions you should be able to make a "soft" shell around your 
container and pass that shell mapping non-soft functions to soft ones, 
ensuring only soft functions can be called. It could look like this:

	insertAtRandomPlace(myContainer.soft, element);

Now you know insertAtRandom won't and *can't* invalidate your 
iterators/ranges, and you don't need to write a separate 
"softInsertAtRandom" that only calls soft functions.

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/