Re: some trivial questions?

[Robert A Duff <bobduff@TheWorld.com>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:

> And we still need distinction between them in protected objects. But
> that is the issue of conflation of dedicated output with no-effects.

Making protected functions special in that way was a
mistake, I think.

>> I'd also prefer that function results and 'out' parameters
>> have identical semantics, which they don't in Ada.
>
> Yes, but there are syntax problems with that:
>
>    procedure Generate_Two_Strings (X, Y : out String);
>
> How do I declare
>
>    X, Y : constant String := Generate_Two_Strings;

Something like:

    X, Y : constant String;
    Generate_Two_Strings (X, Y);

could be made to work.  But that's nothing like Ada.

> How do I do
>
>    2 x Ada.Text_IO.Put_Line (Generate_Two_Strings);

Store them in constants, I guess.

>> But you don't want use_clauses that are
>> nested deep inside some block_statement to imply a "with".
>
> Why not?

Because the with's show the overall structure of the program,
so should be near the top of each package.  (I'd prefer inside
the package, rather than before it.)

> BTW, there is no reason why "with" should not be nested. If a unit can
> depend or not on a unit so a block can. One could even invent some
> interesting elaboration rules for nested "with"s. (:-)) And in effect
> nested "with" do exist for separate bodies.

The rules about subunits are just plain weird.  They confuse the
issues of visibility/dependence and separate compilation.

>> I think nested packages and child packages should have identical
>> semantics (so "with" should apply to both).  That was probably
>> impossible, because child packages were invented too late.
>
> Yes. E.g. what if nested package instantiation would not imply "with"?
> Should the similar [flawed] logic apply here as to "use"?

I don't understand those questions.

- Bob