Re: Elaboration and parameters

[mcsun!fuug!prime!mits!rkaivola@uunet.uu.net (Risto Kaivola)]

Several people have pointed out that the original program is
no good for illuminating the issue because it won't be capable
of being bound.  The reason that the example turned out incorrect
is that I had actually a longish, working sample program, and
decided to strip it down a bit, and didn't bother to check the
new version even by compiling it.  Yes, I should have known better,
but I though it obvious it would work :-).  Nevertheless, you all
understood my intent correctly.  In case someone is interested, here
is the original example program, which should be correct apart from
possible types made in keying it in for this post.

-------------------- [sample program] --------------------

--- Compilation unit 1 ---
package P1 is
  MY_EXCEPTION : exception;

  subtype S is INTEGER range 0 .. 1;
  function EXCEPT(ARG : S) return S;

end P1;


--- Compilation unit 2 ---
package body P1 is
  function EXCEPT(ARG : S) return S is
  begin
    raise MY_EXCEPTION;
    return S(0);
  end EXCEPT;
end P1;


--- Compilation unit 3 ---
with P1;

package P2 is
  procedure PROC(ARG : P1.S);
end P2;


--- Compilation unit 4 ---
package body P2 is
  procedure PROC(ARG : P1.S) is
  begin
    null;
  end PROC;
end P2;


--- Compilation unit 5 ---
with TEXT_IO; use TEXT_IO;
with P1, P2;
pragma ELABORATE(P1);
-- Note: no ELABORATE pragma for P2.

procedure MY_MAIN is
  OBJ : P1.S := 0;
begin
  P2.PROC(P1.EXCEPT(OBJ));
    -- What happens here if the body of P2 has not yet been elaborated?
exception
  when PROGRAM_ERROR =>
    PUT("NE");
  when P1.MY_EXCEPTION =>
    PUT("E");
end MY_MAIN;

----------------- [end of program] -----------------

But anyway, if one of the exception handlers of the procedure MY_MAIN is
executed, the consensus seems to be that it is implementation dependent
whether NE or E is put, or are you of a different opinion?
 

--
Risto Kaivola
(Internet address:   rkaivola@mits.mdata.fi)