sorted_vector, constness, pointers, and structs

[Stephan Bergmann]

On 07/18/2012 08:09 PM, Lubos Lunak wrote:
>   What you want is broken. It is definitely broken from the theoretical point
> of view, since modifying the items may change the sort order.

While one can argue that it is broken, in practice I would not bother 
trying too hard to make the code safe against shooting-in-one's-foot at 
the expense of simplicity.  Whether or not making non-const element 
access available for sorted_vector<T,C> is safe depends on both T 
(element type) and C (comparison function), and e.g. adding a 
specialization so that sorted_vector<T*> only gives access to T const* 
can be OK or overly restrictive.

Quoting an answer I inadvertently only sent to Noel directly:

"Yeah, the 'only give const element access to avoid element 
modifications that invalidate container invariants' strategy is 
apparently not perfect.

"If you do need non-const access, there's no way around it than to offer 
it---and being careful not to accidentally invalidate the container's 
sortedness."

Stephan