Newsgroups: comp.lang.apl
Path: watmath!watserv1!utgpu!cs.utexas.edu!qt.cs.utexas.edu!yale.edu!jvnc.net!phage!wchang
From: wchang@cshl.org (Bill Chang)
Subject: Re: APL slash bang (Repost)
Message-ID: <1992Mar20.182145.20927@cshl.org>
Summary: Teaching APL
Sender: news@cshl.org (NO MAIL)
Organization: Cold Spring Harbor Laboratory
References: <1992Mar16.201303.29862@cshl.org> <LIBERTE.92Mar18125603@birch.cs.uiuc.edu> <1992Mar19.181946.29775@cco.caltech.edu>
Date: Fri, 20 Mar 92 18:21:45 GMT
Lines: 43

In article <1992Mar19.181946.29775@cco.caltech.edu> ssr@vortex.caltech.edu 
(Steve Roy) writes:
>
>... I fail to see the point of reducing
>the whole suite of operators to every possible combination of
>punctuation marks...
>
>Come on guys, what is the point?
>
>Steve Roy
>ssr@ama.caltech.edu

This is an exaggeration :-) just as it is an exaggeration to call J
a language of $&#@*&#!'s.  J uses x x. x: where x is a letter or a
punctuation mark; APL/! uses x x. ~x ~x. where x is taken only from 
a small set of punctuation marks (except v. for "or" and other "initials"
for non-ISO APL operators such as c. for enclose; o. for box/objectify).  
Dot . signifies extension, tilde ~ signifies oppositeness.  There is 
supposed to be some logic in the design :-)  

Honestly, I think such efforts as these _clarify_ the design of APL 
to some degree, and may actually contribute to the teaching of APL.  
APL/! is described in a single page (typewriter pitch), with six
classes of operators (arithmetic; numerical; logical and comparison; 
structural; special/APLish; and nested arrays) plus syntactic 
constructs.  There is uniformity in letter combinations, across 
operators of similar type or function.  In fact an operator's letter
combination _hints_ at its type.

Question: Does the use of letter combinations (of familiar symbols)
necessarily detract from the teaching of APL concepts, compared to the 
use of special, unfamiliar symbols?

Question: Does APL/! _appear_ to suffer more or less, _compared to APL_, 
from the "too many operators" syndrome?


-- Bill Chang (wchang@cshl.org)          Cold Spring Harbor Lab., NY

p.s. Now J is more complicated (read: richer) but Iverson et al.'s original 
APL\? (is it really APL\? or just APL? ? :-) specification fits in a 
typeset page (two columns, rather small type).

