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From: pem@frankland-river.aaii.oz.au (Paul E. Maisano)
Newsgroups: comp.lang.perl
Subject: Re: Creating a reference to an array index
Message-ID: <1366@frankland-river.aaii.oz.au>
Date: 19 Mar 90 05:48:40 GMT
References: <1361@frankland-river.aaii.oz.au> <1362@frankland-river.aaii.oz.au>
Organization: Australian AI Institute
Lines: 38

In article <1362@frankland-river.aaii.oz.au>, I (Paul E. Maisano) write:
> For anyone interested &ref can be defined as follows:
> 	sub ref {
> 		local($tmp);
> 		grep($tmp = *_, $_[0]);
> 		$tmp;
> 	}
> This routine could be made more general by returning an array of
> references for each argument. Ie. you could write,
> 	local(*x, *y, *z) = &ref($x[1], $y[0], $z[2]);

The generalized version is:
    sub ref {
	local(@stab);
	grep(push(@stab,*_),@_);      # kludge to get at symtab entries
	wantarray ? @stab : $stab[0]; # contains the binary symtab data
    }

> You could even set things up so that two arrays share elements!!

Ignore that. As far as I can tell there is no way whatsoever in the current
version of perl to make an array element reference something else. I agree
that it's probably not of any real use anyway.
The reason I think it is impossible, is that the only way you can make
something reference another symbol in perl is to use the type globbing syntax. 
And you aren't allowed to do "*LVALUE = ..." only "*NAME = ...".
In other words, you can't name an array element; only the array.

BTW,
I would also like to see gethostname (and some version of timelocal) in perl.
[But I've already voted for these so it doesn't count, right!? :-]
 
------------------
Paul E. Maisano
Australian Artificial Intelligence Institute
1 Grattan St. Carlton, Vic. 3053, Australia
Ph: +613 663-7922  Fax: +613 663-7937
Email: pem@aaii.oz.au   UUCP: {uunet,mcsun,ukc,nttlab}!munnari!aaii.oz.au!pem