Re: purpose of 10486:4e64fbbd5c58

[Jaroslav Hajek]

On Wed, May 5, 2010 at 8:28 PM, John W. Eaton <address@hidden> wrote:
> On 30-Apr-2010, Jaroslav Hajek wrote:
>
> | The reason is that if isindex (I) is true, I expect isindex ([1; I])
> | to be also true, expect it to be usable in sub2ind etc. If there *has*
> | to be an iconsistency like this, I'd prefer it to be as non-intrusive
> | as possible.
>
> OK.  Since I'm adding this (mis)feature only to allow people to run
> existing Matlab code with Octave and Matlab doesn't seem to have
> isindex, I don't expect this to cause trouble for them.
>
> | I understand your motivation for this, though I still consider this to
> | be the same kind of misfeature like the short-circuiting & and |
> | operators. As I said, I've exhausted my arguments. The decision is up
> | to you.
>
> I checked in the following change:
>
>  http://hg.savannah.gnu.org/hgweb/octave/rev/1834132fb50b
>
> It's the same as the last patch I proposed, except it avoids using
> feval to call Fwarning to set the warning state so overloading can't
> cause trouble.
>
> The (stupidly inconsistent, I agree) behavior is only enabled if the
> Octave:allow-noninteger-ranges-as-indices warning state is set to "on"
> or "off".  If Octave is started with --traditional, the default value
> is "on".  Otherwise, the default is "error".
>
> jwe
>

Now I'm getting this:

octave:1> (1:10)(1.1:10.1)
error: rounding non-integer range used as index to nearest integer

This error message is really confusing.

Further, the following no longer works:

a = rand (1, 10);
idx = 1.1:10.1;

try
  b = a(idx);
catch
  [err, id] = lasterr ();
  if (any (strcmp (id, {"Octave:invalid-index", "Octave:index-out-of-bounds"})))
    disp ("indexing error occured");
  else
    rethrow (lasterror);
  endif
end_try_catch

I think my original solution was better in that it left the normal
behavior intact. If you really insist on the warning ID solution, I
think the message should be just "non-integer range used as index".

I propose to revert 10605:1834132fb50b and apply the patch I sent
earlier (after completing it).

regards

-- 
RNDr. Jaroslav Hajek, PhD
computing expert & GNU Octave developer
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz