Re: Static vs dynamic evaluation anomaly?

[Stefan Lucks <lucks@th.informatik.uni-mannheim.de>]

On Fri, 9 Feb 2007, Jeffrey R. Carter wrote:

> OK. I would say that this is a compiler error. But I can still see how
> the compiler writer could argue that it is not.

OK, does the following test case convince you, that the compiler writer
cannot reasonably deny that the compiler is false (if -gnatp or no
compiler options are chosen)?

The only kind of defense on the side of the compiler writer I can still
imagine is that gnat without the -gnato option isn't an Ada compiler, but
rather a compiler for a language with an Ada syntax but a non-Ada
semantic.

---

with Ada.Text_IO;
use  Ada.Text_IO;

procedure test273 is
  type Six_Bits is mod 2**6;
  X: constant Six_Bits := 31;
  Z: constant Integer  := 31;
  Outside : Boolean;
begin
  for J in 0..9 loop
    Outside := True;
    Put (Integer 'Image         (J) &
         Six_Bits'Image  (X * 2**J) );
    for I in Six_Bits loop
      if (X * 2**J) = I then
        Put(" equal to" & Six_Bits'Image(I));
        Outside := False;
      end if;
    end loop;
    if Outside then
      Put(" (value NOT IN");
    else
      Put(" (value in");
    end if;
    Put_Line(Six_Bits'Image(Six_Bits'First) & " .." &
             Six_Bits'Image(Six_Bits'Last) & ")!"    );
  end loop;
end test273;

---

gnatmake test273

---

./test273
 0 31 equal to 31 (value in 0 .. 63)!
 1 62 equal to 62 (value in 0 .. 63)!
 2 124 (value NOT IN 0 .. 63)!
 3 248 (value NOT IN 0 .. 63)!
 4 240 (value NOT IN 0 .. 63)!
 5 224 (value NOT IN 0 .. 63)!
 6 192 (value NOT IN 0 .. 63)!
 7 128 (value NOT IN 0 .. 63)!
 8 0 equal to 0 (value in 0 .. 63)!
 9 0 equal to 0 (value in 0 .. 63)!

-- 
Stefan Lucks      Th. Informatik, Univ. Mannheim, 68131 Mannheim, Germany
            e-mail: lucks@th.informatik.uni-mannheim.de
            home: http://th.informatik.uni-mannheim.de/people/lucks/
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