Re: Constructors with multiple inheritance

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

On Sat, 12 Nov 2011 07:30:29 -0800 (PST), Rego, P. wrote:

>>   function Construct (aValue: Integer; aName: Integer)
>>                       return Par_Class is
>>   begin
>>     return (theValue => aValue,
>>             theName  => aName);
>>   end Construct;
> 
> In this case function Construct would behave as a C++ static function (or maybe a friend one?)?

That depends on what you mean. In Ada:

1. there is no hidden parameters

2. an operation can be dispatching (virtual) in any combination of
parameters and/or result. But an operation cannot be dispatching in more
than one type (no multiple dispatch). All tags of dispatching parameters
must be same (no multi-methods).

3. there is no static or friend operations as the visibility rules are
based on packages.

The function Construct above is a primitive operation, it is not a
constructor.

Constructors in Ada are implicit, they consist of

1. construction of the components (in an unspecified order, recursively);

2. a call to Initialize if the type is a descendant of
Ada.Finalization.[Limited_]Controlled. (Overridden bodies of Initialize are
not called! I.e. Ada constructors do not traverse derivation path. In
short, aggregation is safe, derivation is not;

3. starting all task components. (Note, tasks are not running when
Initialize is called!)

Destructors act in the reverse order: tasks - Finalize - components.

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