Re: fix null assignment

[John W. Eaton]

On 22-Sep-2008, Jaroslav Hajek wrote:

| On Sat, Sep 20, 2008 at 6:09 AM, John W. Eaton <address@hidden> wrote:
| 
| > I'd prefer to avoid adding a new assign_op.  I think we would have to
| > be careful to also check for op_nul_asn_eq in each place where
| > op_asn_eq is used and that is likely to cause confusion.
| 
| Why? I think it would only require to register the handlers.

I was just looking at the places where we check for op_asn_eq and
thinking that it might be necessary to also check for op_nul_asn_eq,
and that this could lead to a maintenance problem in the future.

| Btw. I don't much like the fact that A(I,:) =[[;[];];] is also a null
| assignment in Matlab; do we really want to copy this behaviour?

No, I don't think it is necessary to have [] and [;] or [,] be exactly
equivalent.  We could have [] (and, for strings, '' and "") be the
only ways of specifying a special nul matrix.  But for compatibility,
we should probably accept the [;] and [,] syntax.

In any case, I don't think my patch is good enough to include at this
point.  I'd be happy to consider your approach instead, if you are
willing to write enough of a patch to show how it would be done.

Thanks,

jwe