Re: Type naming conventions: Any_Foo

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

On 2019-12-06 21:18, Jeffrey R. Carter wrote:
> On 12/5/19 10:51 PM, Dmitry A. Kazakov wrote:
>>
>> Ada standard library uses _Type, e.g.
>>
>> generic
>>     type Element_Type (<>) is private;
>>     with function "=" (Left, Right : Element_Type) return Boolean is <>;
>> package Ada.Containers.Indefinite_Holders
> 
> Yes, and the ARM also includes such abominations as anonymous access 
> types. Just because it's in the ARM doesn't mean it's the best way to do 
> something. Element is be a better name for that formal type.

No, it would be misleading. Element must be reserved for instances of 
the type. They are actual elements. The type of an element is not an 
element, these are two totally different things.

>> There are lots of cases in Ada, you certainly should know that. As a 
>> practical example GtkAda declares all widget types twice:
>>
>>     type Gtk_Button_Record is ...
>>     type Gtk_Button is access all Gtk_Button_Record'Class;
> 
> No well designed library has public access types. You aren't required to 
> use a library that does, and you aren't required to use access types.

I am required to. There must be always be two types in a GUI, one 
referential type and one implementation type. The widget implementation 
object in GtkAda is Gtk_Button_Record. The widget referential object is 
Gtk_Button. It could be a handle or a smart pointer type instead of 
plain pointer, but there is no way to reduce it to a single type. So the 
problem will persist.

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