Re: _Type vs no _Type

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Thu, 04 Nov 2010 06:28:28 +0100, Nasser M. Abbasi <nma@12000.org> a  
écrit:
> Sorry to jump in, I have not read everything in this thread, so may be
> this was mentioned already.
>
> Isn't this whole subject a result of Ada being case insensitive?

If you see C/C++ as a reference. It is more a result of Ada being without  
a separate name-space for types, like Eiffel do. This was previously  
explained.

> If Ada has been case sensitive, then one would write
>
> weapon : Weapon;
>
> and be done with it?
>
> That is one part of Ada I never liked, same for Fortran or any other
> language which is not case sensitive.
That is counter intuitive and dangerous. Counter intuitive because “URL”  
would become a type. This is dangerous, because when you may easily type  
“Id” instead of “id”, which may lead into a program, which could be  
checked as correct, but with a very different behavior (you could even  
imagine this as an error introduced on purpose to pirate an application  
 from the inside). And then, if one start to play with letter casing to  
distinguish between entities, then there is really a trouble.

Could you recommend the following as a good practice ?

    URL : Location_Type;
    url : Identifier_Type; -- Illegal after the latter, luckily

OK, every one can guess what “URL” means. But who can guess what means the  
difference in casing ? (only the author can… while not sure, he/she may  
forget some time later).

I know you probably did not have this kind of tricky usage in mind. But if  
you allow it, be sure this will be used this way sooner or later. This is  
just to say using casing to distinguish type and instance is even worse,  
because the languages which do that, are case sensitive every where, and  
to have “URL” and “url” in the same scope, is legal C/C++. So, let Ada be  
case insensitive and use _Type, this is not the worst.

> But nothing can be done about it, I know.
Will never, for the reason given above (I think there is a rational text  
for that, will look for it someday).


-- 
Si les chats miaulent et font autant de vocalises bizarres, c’est pas pour  
les chiens.