Am 30.10.2013 11:59, schrieb Jonas Maebe:
On 30 Oct 2013, at 10:36, Michael Van Canneyt wrote:
I think it is an error. You declare something as private, and then
you use it in a public function ? If that is not a visibility clash,
I don't know what is :)
The ability to use types in public functions that are not necessarily
visible to users of that function is quite common in Pascal.
Otherwise, for consistency you would also have to give a compile time
error when compiling this:
unit u1;
interface
type
tdynarray = array of integer;
implementation
end.
*********
unit u2;
interface
uses
u1;
function f: tdynarray;
implementation
function f: tdynarray;
begin
end;
end.
**********
program test;
uses
u2;
var
a: array of integer;
begin
a:=f;
end.
***
The tdynarray type is not visible in the program because u1 is not in
its uses clause (it's not in scope whatsoever), and nevertheless there
is no problem to use it. It's of course not exactly the same
(tdynarray isn't declared as private to u1), but at the scope
visibility level it is the same situation as far as I am concerned.
Hmm... but here the compiler can not know whether the unit using u2 has
unit u1 in scope or not. In case of private and protected types the
compiler can know however that code declared externally can never have
access to it (though of course there might be type compatibilities like
your dynamic array example, but most private/protected types should be
records or classes).
Regards,
Sven
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