Re: Porting from Modula-2 to Ada

[Lutz Donnerhacke <lutz@iks-jena.de>]

* Jeffrey Creem wrote:
> "Lutz Donnerhacke" <lutz@iks-jena.de> wrote in message
>> generic
>>   type T(<>) is limited private;
>> procedure Xxx (data : T);
>
> When I have done this I tend to make the generic formal parameter be
> private instead of limited private. There are times when limited might be
> right but almost any time someone makes something limited, the in memory
> representation one would get via the type is somewhat bogus.

generic types define the most restrictive assumptions can be made on every
real type: You can instantiate a limited generic type with an ordinary one.

When removing the limited constraint from the generic definiton, you allow
the generic program to copy variables of the generic type. So you are never
allowed to instantiate this construct with a limited type.

The other way around you are allowed to instantiate, because your real type
fullfills all requirements (and a lot more).

> Also, it is worth checking in the generic body that the 'size of the type
> is a multiple of the 'size of the storage element (or whatever type you
> use to write to the file)

You didn't read my code. :-/