Re: Constructors with multiple inheritance

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

On Thu, 10 Nov 2011 11:16:24 -0700, Jeffrey Carter wrote:

> On 11/09/2011 08:47 PM, Rego, P. wrote:
>>
>> class Par_Class {
>> public:
>>    Par_Class (int aValue, const char *aName);
>>
>> private:
>>    int theValue;
>>    char *theName;
>> };
> 
> private with Ada.Strings.Unbounded;
> 
> package Par is
>     type Class is private;
> 
>     function Create (Value : in Integer; Name : in String);
> private -- Par
>     type Class is record
>        Value : Integer := Integer'First;
>        Name  : Ada.Strings.Unbounded.Unbounded_String;
>     end record;
> end Par;
> 
> package body Par is
>     function Create (Value : in Integer; Name : in String) is
>        -- null;
>     begin -- Create
>        return Class'(Value => Value,
>                      Name  => Ada.Strings.Unbounded.To_Unbounded_String (Name) );
>     end Create;
> end Par;
> 
> No need for tagged types or access types for this example.

No need in unbounded strings either:

   type Class (<>) is private;
   function Create (Value : in Integer; Name : in String) return Class;
private
   type Class (Length : Natural) is record
       Value : Integer := Integer'First;
       Name : String (1..Length);
    end record;

   function Create (Value : in Integer; Name : in String) return Class is
   begin
       return (Length => Name'Length, Value => Value, Name => Name);
   end Create;

IMO, unbounded strings should be used only in two cases:

1. The container type must be constrained (e.g. to place its objects into
arrays etc)

2. The component is varying during object's life.

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