Newsgroups: comp.lang.apl
Path: watmath!watserv1!utgpu!cs.utexas.edu!wupost!darwin.sura.net!jvnc.net!phage!wchang
From: wchang@cshl.org (Bill Chang)
Subject: Re: APL slash bang (Repost)
Message-ID: <1992Mar27.035533.5985@cshl.org>
Summary: Precedence and order of evaluation
Sender: news@cshl.org (NO MAIL)
Organization: Cold Spring Harbor Laboratory
References: <1992Mar23.191155.16119@yrloc.ipsa.reuter.COM>
Date: Fri, 27 Mar 92 03:55:33 GMT
Lines: 22

In article <1992Mar23.191155.16119@yrloc.ipsa.reuter.COM> dgil@ipsaint.ipsa.reuter.COM 
(Gillett, David) writes:
>     First of all:  how do you have a precedence scheme that only applies to
>SOME primitives?  
>
>     Similarly, right-to-left evaluation facilitates a functional style of
>programming without a LISP-like profusion of parentheses.  

I am not convinced that _no_ precedence is the _only_ way to go.  What's wrong
with (1) plus/minus/or (2) times/divide/and (3) power (4) everything else, 
in order of increasing precedence?  

Nial uses left-to-right evaluation in an intuitive way, functional without 
becoming Lispy.  The "trick" is a syntactic device dot . equivalent to a left
parenthesis.

I'm not (necessarily) endorsing either of the above; just want to point out
there _are_ reasonable alternatives.  I agree with Dan LaLiberte that these
issues are less important than some others we have been discussing.


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