Re: Common ancestor (visibility rules)

[dmitry6243@my-deja.com]

In article <8bu64t$60h$1@nnrp1.deja.com>,
Robert Dewar <robert_dewar@my-deja.com> wrote:

> > with A; use A; -- OK with Aonix, error in GNAT
> >(v3.12)
>
> The above is perfectly fine, and compiles fine with all versions
> of GNAT, you are either compiling code different from what
> you quoted, or you have a messed up copy of GNAT.

b-a.adb:1:13: "A" is not a usable package

> No, of course GNAT handles this right. You should perhaps
> publish the ENTIRE code you have that GNAT rejected. You
> gave two quite different examples of code so far, and
> neither had with A; use A; in it.

-------------- a.ads
package A is
   procedure Foo;
end A;
-------------- b.ads
package B is
   procedure A;
end B;
-------------- b.adb
package body B is
   procedure A is separate;
end B;
-------------- b-a.adb
with A; use A;
separate (B)
procedure A is
begin
   Foo;
end A;
===========================================
>gcc -c b-a.adb
b-a.adb:1:13: "A" is not a usable package
b-a.adb:5:04: "Foo" is not visible
b-a.adb:5:04: non-visible declaration at a.ads:2

> I will say the rule once more, after that you really need to
> read and figure it out :-)
>
> You can only WITH a library unit, library units are the units
> that are child units of Standard.
>
> So if you say
>
> with Standard.A;
>
> you are saying that Standard.A is a library unit, i.e. that
> it is a child of Standard, i.e. that its fully qualified nanme
> is Standard.Standard.A.
>
> The fully qualified name always includes Standard, but you can
> NOT use this fully qualified name in a WITH clause!

In other words:

1. Fully qualified names cannot be used in WITH clause;
2. Fully qualified names can be used in USE clause;

Here "fully qualified name" stays for a name beginning from Standard (I
mean the predefined one). As a consequence, WITH and USE clauses use
different names. This is what I meant talking about "two diffrent kinds
of names".

Had I figured it out? (:-))

P.S. You know it for sure. Does ALRM cease to exist? It worked much
better to me. I cannot find a new version, mine is dated 1992! (:-().

Regards,
Dmitry Kazakov


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