Re: Copy vector in Ada

[Maciej Sobczak <see.my.homepage@gmail.com>]

W dniu sobota, 3 listopada 2012 00:45:55 UTC+1 użytkownik Hibou57 (Yannick Duchêne) napisał:

> > Similarly in C++ - if the assignment operator is too costly (or just  
> > impossible) to implement, there is a way to ban it.
> 
> Really? That's a hot news to me. At least at the time I used it (~ 2000),  
> there was nothing like that,

Then you should prepare for an even hotter news: it was "there" always.

> And I'm not even sure there was a way to redefine the copy operation

It was "there" always. The ability to redefine copy operation is a fundamental part of data abstraction. You would not even be able to implement such basic things like a string class without this functionality.
  
I would even say that C++ has a more elegant solution for this problem, as the ability to redefine the assignment operation is orthogonal to other parts of the language and does not interfere with things like polymorphism. Also, banning and redefining are handled in the consistent way (hey, they *are* related issues!), while in Ada these two are done in completely distinct ways - one requires a keyword, while the other requires a derivation from some magic type. Yuck.

-- 
Maciej Sobczak * http://www.msobczak.com * http://www.inspirel.com