Re: References to hash elements?

On Jan 6, 2004, at 9:25 AM, Leopold Toetsch wrote:

> Arthur Bergman <[email protected]> wrote:
>> Hi,
>
>> I am wondering how the references to hash elements are planned to be
>> done? The call to set_ must somehow be delayed until the time is 
>> right.
>
>> $foo = \$hash{key};
>
>> $$foo = "bar";
>
>> $has{key} is now "bar"
>
> There was some discussion WRT that issue months ago. Currently the
> implementation is wrong IMHO. When $hash{key} doesn't exist a new
> PerlUndef is returned (which is fine) but it should be stored in the
> hash too, so that assigning to $foo does The Rigth Thing.
> (Parrot aggregates have reference semantics, so ...)

This may have been discussed previously, but I would think that reading 
a hash should never auto-vivify elements. (That would be contrary to 
the Perl5 semantics, at least.) You may need to return a special 
reference-style PMC which knows how to get back to the original hash if 
you assign to it, but the hash itself shouldn't grow entries.

JEff