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Date: 7 Oct 92 12:03:37 GMT
From: news.univie.ac.at!chx400!sicsun!disuns2!disuns2.epfl.ch!sidou@uunet.uu.ne
t  (Dominique Sidou)
Subject: Re: Problem with inefficiency and records with variant parts
Message-ID: <SIDOU.92Oct7130337@litsun.epfl.ch>
List-Id: <comp.lang.ada>

First, I want to reformulate the problem, I think it
was not enough precise in my first post:

Suppose:

PACKAGE qwe IS 

  subtype t1 is Integer;
  type t2 is array(1..1000) of Integer;
  type t3 is array (1..1000) of Boolean;

  subtype st is integer range 1..3;

  type t (s : st := 1) is record
    case s is
      when 1 => c1 : t1;
      when 2 => c2 : t2;
      when 3 => c3 : t3;
    end case;
  end record;

  procedure fillt1(v1 : in out t1);
  procedure fillt2(v2 : in out t2);
  procedure fillt3(v3 : in out t3);
  procedure fillt(v : in out t; s : in st);

END qwe;

package body qwe is

  procedure fillt1(v1 : in out t1) is
  begin
    v1 := 1;
  end fiilt1;

  procedure fillt2(v2 : in out t2) is
  begin
    for i in v2'range loop
      v2(i) := 2;
    end loop;
  end fillt2

  procedure fillt3(v3 : in out t3) is
  begin
    for i in v2'range loop
      v3(i) := true;
    end loop;
  end fillt3;

  procedure fillt(v : in out t; s : in st) is
  begin
      -- ?? How can I Do ??
      -- to cast v to v(s) and then call
      -- the corresponding filling procedure
      -- without any copy of a structure of
      -- type t2 or t3.
    case s is
      when 1 =>
	v := (s => 1, c1 => 0);
        fillt1(v.c1);
      when 2 =>
        v := (s => 2, c2 => (others => 0)); -- useless copy to avoid !!
        fillt1(v.c2);
      when 3 =>
	v := (s => 3, c3 => (others => false)); -- useless copy to avoid !!
        fillt1(v.c3);
    end case;
  end fillt;

end qwe;

I think now the problem is well formulated.

Precisions:
1: I know that if my components were
references it would be easy. But i have to deal
with static structures.

2: Working with Verdix Ada 6.0.3 on Sun4/SunOs 4.1.1

Thanks in advance for any ideas,

/DS.

Sidou Dominique, Ecole Polytechnique Federale de Lausanne,
DI-LIT-INN138, Ecublens, CH-1015 Lausanne, Suisse
tel: 693.26.48. e-mail: sidou@litsun.epfl.ch
--

Sidou Dominique, Ecole Polytechnique Federale de Lausanne,
DI-LIT-INN138, Ecublens, CH-1015 Lausanne, Suisse
tel: 693.26.48. e-mail: sidou@litsun.epfl.ch