Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: <HANDLE> = @array?
Message-ID: <7163@jpl-devvax.JPL.NASA.GOV>
Date: 24 Feb 90 18:50:18 GMT
References: <15193@bfmny0.UU.NET> <1990Feb23.190121.2591@iwarp.intel.com> <15202@bfmny0.UU.NET>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 38

In article <15202@bfmny0.UU.NET> tneff@bfmny0.UU.NET (Tom Neff) writes:
: Just for the record, if I toss something out for discussion right now
: it's NOT because I want it to go in Patch 9!  Like everyone else, I
: await that patch with no further embellishment (and eagerly!).

The problem is that it takes 4-5 contiguous hours to put a patch together
and test it, and the usual embellishment only takes an hour or so to add.

: Now, how about easy array inserts and deletes via slice operations?
: 
: 	push(@array[1..$n], $elt1, $elt2...);
: and
: 	$elt = pop(@array[1..$n]);

It's kindof weird to use array slices for that, since you have to supply
useless information.  And the semantics of slices are that they are
equivalent to a list of individual scalars, which I don't want to change.

What we need is some equivalent to the substr() function when used as an
lvalue--if the thing you assign is the same length, it changes in place;
if it's longer, the array grows, and if it's shorter, the array shrinks.
Assignment to a slice would be a reasonable syntax, but that already means
something different, alas.  And what would

	$elt = pop(@array[1,8,4])

mean?

Perhaps

	subary(@array, $n, 0) = ($elt1, $elt2, ...);    # your push

	$elt = $array[$n];				# your pop
	subary(@array, $n, 1) = ();

Open to suggestions.

Larry