[boost] Re: Collection concept

From: jsiek_at_[hidden]
Date: 2000-01-12 15:36:52

Greg Colvin writes:
 > I have also not been following this thread, but I agree with
 > Howard's take below.  So if you are trying to state general
 > container requirements for proxied containers you will need
 > to look at all the algorithms.

"all" is a pretty strong word :)

Here's what I've looked at:
  all the algorithms in MTL and GGCL

These algorithms often use 2D containers, so an expression
like this is *very* common:

 Collection::iterator i;
 Collection::value_type::iterator j;

 j = (*i).begin();

Now if the Collection uses a Proxy reference type, then this *will*
break.

Hence the conditional requirement for member access that is now in the
Collection concept.

I do not know of any examples that argue for the more
flexible position of unconditionally allowing proxies.
If anyone does, please let me know.

Cheers,

Jeremy