with child: access to parent

with child: access to parent

[Peter Hermann]

We happened to detect following non-expected 
language permission (at least by gnat3.13p):

--------------------
with pak.child;
procedure mytest is
begin
   pak.hugo:=1;
   end;
--------------------
package pak is
   hugo :integer;
   end pak;
--------------------
package pak.child is
end;
--------------------

This may be perfectly legal but
I can not find the appropriate rule 
in the LRM.

-- 
Peter Hermann Tel+49-711-685-3611 Fax3758 ica2ph@csv.ica.uni-stuttgart.de
Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen
http://www.csv.ica.uni-stuttgart.de/homes/ph/
Team Ada: "C'mon people let the world begin" (Paul McCartney)

Re: with child: access to parent

[Pat Rogers]

"Peter Hermann" <ica2ph@iris16.csv.ica.uni-stuttgart.de> wrote in message
news:9pc3jp$old$1@infosun2.rus.uni-stuttgart.de...
> We happened to detect following non-expected
> language permission (at least by gnat3.13p):
>
> --------------------
> with pak.child;
> procedure mytest is
> begin
>    pak.hugo:=1;
>    end;
> --------------------
> package pak is
>    hugo :integer;
>    end pak;
> --------------------
> package pak.child is
> end;
> --------------------
>
> This may be perfectly legal but
> I can not find the appropriate rule
> in the LRM.



10.1.2 Context Clauses - With Clauses

6     A library_item is mentioned in a with_clause if it is denoted by a
library_unit_name or a prefix in the with_clause.



---
Patrick Rogers                       Consulting and Training in:
http://www.classwide.com          Real-Time/OO Languages
progers@classwide.com               Hard Deadline Schedulability Analysis
(281)648-3165                                 Software Fault Tolerance

Re: with child: access to parent

[Marc A. Criley]

Pat Rogers wrote:
> 
> "Peter Hermann" <ica2ph@iris16.csv.ica.uni-stuttgart.de> wrote in message
> news:9pc3jp$old$1@infosun2.rus.uni-stuttgart.de...
> > We happened to detect following non-expected
> > language permission (at least by gnat3.13p):
> >
> > --------------------
> > with pak.child;
> > procedure mytest is
> > begin
> >    pak.hugo:=1;
> >    end;
> > --------------------
> > package pak is
> >    hugo :integer;
> >    end pak;
> > --------------------
> > package pak.child is
> > end;
> > --------------------
> >
> > This may be perfectly legal but
> > I can not find the appropriate rule
> > in the LRM.
> 
> 10.1.2 Context Clauses - With Clauses
> 
> 6     A library_item is mentioned in a with_clause if it is denoted by a
> library_unit_name or a prefix in the with_clause.

Which means that

with pak.child;

is equivalent to:

with pak;
with pak.child;


Marc A. Criley
Senior Staff Engineer
Quadrus Corporation
www.quadruscorp.com

Re: with child: access to parent

[Peter Hermann]

Pat Rogers <progers@classwide.com> wrote:
> 10.1.2 Context Clauses - With Clauses
> 6     A library_item is mentioned in a with_clause if it is denoted by a
> library_unit_name or a prefix in the with_clause.

does this mean, that

with a.b.c.d;

is equivalent to

with a;
with a.b;
with a.b.c;
with a.b.c.d;

?

-- 
Peter Hermann Tel+49-711-685-3611 Fax3758 ica2ph@csv.ica.uni-stuttgart.de
Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen
http://www.csv.ica.uni-stuttgart.de/homes/ph/
Team Ada: "C'mon people let the world begin" (Paul McCartney)

Re: with child: access to parent

[Ted Dennison]

In article <9pchrq$8vt$1@infosun2.rus.uni-stuttgart.de>, Peter Hermann says...
>with a.b.c.d;
>
>is equivalent to
>
>with a;
>with a.b;
>with a.b.c;
>with a.b.c.d;

I'm not sure if that's what the LRM passage is saying, but this is the case. Try
it out yourself. Essentially, all those "with"s but the last one are redundant.

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html
          home email - mailto:dennison@telepath.com
No trees were killed in the sending of this message. 
However a large number of electrons were terribly inconvenienced.

Re: with child: access to parent

[Pat Rogers]

"Peter Hermann" <ica2ph@iris16.csv.ica.uni-stuttgart.de> wrote in message
news:9pchrq$8vt$1@infosun2.rus.uni-stuttgart.de...
> Pat Rogers <progers@classwide.com> wrote:
> > 10.1.2 Context Clauses - With Clauses
> > 6     A library_item is mentioned in a with_clause if it is denoted by a
> > library_unit_name or a prefix in the with_clause.
>
> does this mean, that
>
> with a.b.c.d;
>
> is equivalent to
>
> with a;
> with a.b;
> with a.b.c;
> with a.b.c.d;

Yes, exactly right.

Re: with child: access to parent

[Peter Hermann]

Marc A. Criley <mcqada@earthlink.net> wrote:
> Which means that

> with pak.child;

> is equivalent to:

> with pak;
> with pak.child;

thank you.
10.1.2(6) does not clearly state this fact.

-- 
Peter Hermann Tel+49-711-685-3611 Fax3758 ica2ph@csv.ica.uni-stuttgart.de
Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen
http://www.csv.ica.uni-stuttgart.de/homes/ph/
Team Ada: "C'mon people let the world begin" (Paul McCartney)

Re: with child: access to parent

[Pat Rogers]

"Peter Hermann" <ica2ph@iris16.csv.ica.uni-stuttgart.de> wrote in message
news:9pcip8$8vt$2@infosun2.rus.uni-stuttgart.de...
> Marc A. Criley <mcqada@earthlink.net> wrote:
> > Which means that
>
> > with pak.child;
>
> > is equivalent to:
>
> > with pak;
> > with pak.child;
>
> thank you.
> 10.1.2(6) does not clearly state this fact.

You asked for the rule, not the exegesis!  :-) :-)

Re: with child: access to parent

[Wes Groleau]

Ted Dennison wrote:
> it out yourself. Essentially, all those "with"s but the last one are redundant.

Some style guides suggest _always_ listing the parent specifically
if anything in it is referenced.  I guess the idea is to prevent
compile errors if the child references are removed.  But how many
places actually take the trouble of removing unused withs?  And
what is the more expensive way to find the need to add one--to
carefully eyeball the code, or to compile and look at the messages?

-- 
Wes Groleau
http://freepages.rootsweb.com/~wgroleau

Re: with child: access to parent

[Peter Hermann]

Wes Groleau <wwgrol@sparc01.ftw.rsc.raytheon.com> wrote:
> Some style guides suggest _always_ listing the parent specifically
> if anything in it is referenced.  I guess the idea is to prevent
> compile errors if the child references are removed.  But how many
> places actually take the trouble of removing unused withs?  And
> what is the more expensive way to find the need to add one--to
> carefully eyeball the code, or to compile and look at the messages?

Of course it is a welcome convenience to save a couple of "with"s.
An advanced binder/linker will automagically leave out heavy-weight
unused parts of executable code, anyway.
For readable programs I am considering a largely use-less style
more favorable than the above (style-) rule.

-- 
Peter Hermann Tel+49-711-685-3611 Fax3758 ica2ph@csv.ica.uni-stuttgart.de
Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen
http://www.csv.ica.uni-stuttgart.de/homes/ph/
Team Ada: "C'mon people let the world begin" (Paul McCartney)

Re: with child: access to parent

[dale]

Peter Hermann wrote:

> does this mean, that
> 
> with a.b.c.d;
> 
> is equivalent to
> 
> with a;
> with a.b;
> with a.b.c;
> with a.b.c.d;

Probably worth mentioning that the semantics for "use" are
not the same.
e.g. 

   use a.b.c.d; 

is not equivalent to...

   use a;
   use a.b;
   use a.b.c;
   use a.b.c.d;


Dale

Re: with child: access to parent

[Jean-Pierre Rosen]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 603 bytes --]


"Pat Rogers" <progers@classwide.com> a �crit dans le message news: X4ku7.7990$Eq3.3697458203@newssvr11.news.prodigy.com...
> > does this mean, that
> >
> > with a.b.c.d;
> >
> > is equivalent to
> >
> > with a;
> > with a.b;
> > with a.b.c;
> > with a.b.c.d;
>
> Yes, exactly right.
>
Note however that if you really want the child and not the parents, you can do the following:

with a.b.c.d;
package a_b_c_d renames a.b.c.d;

with a_b_c_d;
...

--
---------------------------------------------------------
           J-P. Rosen (rosen@adalog.fr)
Visit Adalog's web site at http://www.adalog.fr

Re: with child: access to parent

[Pat Rogers]

"Peter Hermann" <ica2ph@iris16.csv.ica.uni-stuttgart.de> wrote in message
news:9q4cjm$jnf$1@infosun2.rus.uni-stuttgart.de...
> Jean-Pierre Rosen <rosen@adalog.fr> wrote:
> > Note however that if you really want the child and not the parents,
> > you can do the following:
>
> > with a.b.c.d;
> > package a_b_c_d renames a.b.c.d;
>
> > with a_b_c_d;
> > ...
>
> does that mean package a_b_c_d is a unit on library level
> in its own right?

Yes, it is a library unit renaming, as is the case, for example, with
Text_IO (which renames Ada.Text_IO) by 10.1.1{4}:

library_item ::= [private] library_unit_declaration
  | library_unit_body
  | [private] library_unit_renaming_declaration


> If yes, how to map into the gnat file naming system?

a_b_c_d.ads

Re: with child: access to parent

[Peter Hermann]

Jean-Pierre Rosen <rosen@adalog.fr> wrote:
> Note however that if you really want the child and not the parents,
> you can do the following:

> with a.b.c.d;
> package a_b_c_d renames a.b.c.d;

> with a_b_c_d;
> ...

does that mean package a_b_c_d is a unit on library level 
in its own right?
If yes, how to map into the gnat file naming system?

-- 
Peter Hermann Tel+49-711-685-3611 Fax3758 ica2ph@csv.ica.uni-stuttgart.de
Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen
http://www.csv.ica.uni-stuttgart.de/homes/ph/
Team Ada: "C'mon people let the world begin" (Paul McCartney)

Re: with child: access to parent

[Simon Wright]

Wes Groleau <wwgrol@sparc01.ftw.rsc.raytheon.com> writes:

>                                                      But how many
> places actually take the trouble of removing unused withs? 

Since I started asking GNAT to tell me about unused things (-gnatwu),
I (we) do!

-- 
Simon Wright                         Email: simon.j.wright@amsjv.com
Alenia Marconi Systems                     Voice: +44(0)23 9270 1778
Integrated Systems Division                  FAX: +44(0)23 9270 1800