Re: Limited_Controlled and constructor functions

[Maciej Sobczak <no.spam@no.spam.com>]

Dmitry A. Kazakov wrote:

>> In C++ it's two lines of code or even half:
>>
>> class MyClass : boost::noncopyable
>> ...
> 
> Huh, C++ has even weaker means to describe formal types contracts. It has
> dire <class T>. In Ada there is limited, tagged, range <> etc. Far too
> weak, IMO, but still better than C++.

Yes, except that I'm not suprised by what C++ offers with regard to 
class definitions. I was very surprised by the semantics of Controlled 
and Limited_Controlled and their funny effects on other parts of my program.

>>  > send them over IP...
>>
>> Then we're talking about serialization.
> 
> Egh, no, serialization is ordering in time.

You are right. Me too:

http://en.wikipedia.org/wiki/Serialization

> To be able to copy is about
> lack of identity and memory-isotropy.

Not really. Memory isotropy (cool technical buzz, btw ;-) ) is about 
memcpy and memmove. Copy semantics is about what happens when you use 
relevant language constructs. If memory isotropy is a property of any 
given type, then copy semantics can be automatically derived. Otherwise 
it has to be explicitly defined.

>> Limited types don't forbid it.
> 
> Limited types is a kludge.

A particularly nasty one.

> There should be a simpler and clearer way to say
> that the thingy has no visible compiler-generated copy constructor, no
> equality, no aggregates, no assignment

Amen.


-- 
Maciej Sobczak : http://www.msobczak.com/
Programming    : http://www.msobczak.com/prog/