Newsgroups: comp.lang.apl
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!news.cs.indiana.edu!maytag!watmath!ljdickey
From: ljdickey@watmath.waterloo.edu (L.J.Dickey)
Subject: Re: Rank 0 catenation.
Message-ID: <1991Jun26.171808.3998@watmath.waterloo.edu>
Keywords: rank, catenate , array , box
Organization: University of Waterloo
References: <1991Jun24.161151.12366@watmath.waterloo.edu> <594@kepler1.kepler.com>
Date: Wed, 26 Jun 1991 17:18:08 GMT
Lines: 32

In article <594@kepler1.kepler.com> rjfrey@kepler1.UUCP (Robert J Frey) writes:
> ...
> 
>Does anyone know why people seem to feel that "data nesting" as in APL2
>enclosed variables and "data referencing" as in J boxed nouns are incompatible
>with one another? They are probably implemented pretty much the same way as a
>data structure, the difference being the way the various verbs/functions of
>the language deals with them.

They need not be incompatible.  I would refer you to the programming
language APL90, designed by Jean-Jacques Girardot, of the School of
Mines in St-Etienne, France, and to papers by Girardot.   With APL90,
which runs only on Macintosh computers, one may have both types of
generalized arrays in your workspace at the same time.

It was Girardot who made at the conference APL90 what is, I believe,
the first public observation that boxed arrays behave very much like
pointers to arrays.  In his paper, "Arrays and References", there is
a section called "A comparison of nested arrays, boxed arrays and
references" in which he notes a profound analogy between boxed arrays
and References.

Girardot may be reached at  girardot@cambur.emse.fr .  I don't know
if he reads this news group.

						Lee Dickey

-- 
Prof L.J. Dickey, Faculty of Mathematics, U of Waterloo, Canada N2L 3G1
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