Re: What would you like in Ada202X?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Wed, 9 May 2012 19:30:53 -0500, Randy Brukardt wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
> news:1drg0pngpz60n$.13rm2wqyteyli$.dlg@40tude.net...
>>
>> But how would you have Root_Integer'Class without multiple inheritance?
> 
> Not sure what "inheritance" has to do with it, multiple or not. Most of 
> these things have properties which are generated anew for each type -- and 
> the fact that these are *not* inherited is very important to making them 
> work properly.

Of course they are inherited because they are same and treated as being
same. In *all* cases where Ada does not do the latter it gets in trouble,
e,g. when "+" gets overloaded for the same signature.

BTW interface /= implementation. Whatever the compiler generates and how is
irrelevant to the question if an interface is inherited.

>> What about Root_Discrete'Class, Root_Scalar'Class, Root_Numeric'Class and
>> dozens other classes it belongs to? You cannot order interfaces like these
>> in one string.
> 
> Who's trying to order anything?

You must force classes in one line if only single inheritance allowed. That
means precisely that for any two classes they either do not intersect or
else one is contained by another. This is an absolutely unrealistic
constraint.

> There would be a problem if you 
> wanted to gather arbitrary sets of properities together (things not defined 
> by Ada to be classes), but that's not a sensible thing to do, especially in 
> the existing Ada language framework.

I cannot decipher this, sorry. Are "things defined by Ada to be classes"
allowed to construct new classes? [So far some of them were] Are new
classes classes? [This was also true] Can these user-defined classes be
used to create other classes? [Ditto].

What the point?

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de