Re: discriminant questions

["Randy Brukardt" <randy@rrsoftware.com>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:19iim6m72b6s4$.qe1pwkufdkzn$.dlg@40tude.net...
...
> For generic programming you need Delete working in the same (specified) 
> way
> for all container types of the set. Its effect on all iterators must be
> defined and same. My point and the purpose of the example was that this is
> extremely difficult to achieve, if possible.

Humm, I wouldn't find that difficult to achieve at all. Surely if you are 
using Ada.Containers, Delete works the same way in all of them. Similarly, 
if you are building containers that are intentionally similar to 
Ada.Containers, you again will have the same effects.

I realize that there is a very wide universe of container designs out there. 
A large part of the point of Ada.Containers was to select one and 
standardize on it -- since many of the choices are essentially equivalent, 
choosing a single solution was pretty much the only way to get some leverage 
on container libraries.

So, for the vast majority of uses, Ada.Containers and extensions of it will 
be sufficient, and for those iterator semantics is well-defined. If you 
build you own iterators away from the Ada.Container model, you'll have to 
define your own semantics for things like Delete -- but one presumes that 
you have a good reason for doing that, so it should be worth the effort.

                                 Randy.