Newsgroups: comp.lang.apl
Path: watmath!watserv2.uwaterloo.ca!torn!nott!uotcsi2!news
From: cbbrowne@csi.uottawa.ca (Christopher Browne)
Subject: Questions of the Day
Message-ID: <1993Mar5.054012.11402@csi.uottawa.ca>
Sender: news@csi.uottawa.ca
Nntp-Posting-Host: prgh
Organization: Dept. of Computer Science, University of Ottawa
Date: Fri, 5 Mar 93 05:40:12 GMT

Here's some stuff I can't get to work.

a) p. - Polynomial.

None of the polynomial "things" seem to work.

The discussion ABOUT p. in the Dictionary shows examples of verbs that
are equivalent to the different meanings of p.; I tried some of 'em
successfully.  

Unfortunately, I've been less successful with trying to actually use
p.  Anybody got a working example?

b) 0!:55 - Terminate Session

Doesn't want to be recognized.  When I installed a readline interface
that uses C-d as a delete key, it became rather difficult to terminate
J sessions :-(.  I hacked in the classic )off command from APL, but
that's not an ideal solution.

I thought it might be a problem with my copy (6.2 compiled by myself
for Atari ST), but tried it on the 386 version I got with my
dictionary, and it didn't like 0!:55 either.

It just returns the command as the result.

c) So what are 0: to 9: for, anyways?
(Page 97, Dictionary/Intro)

In playing with 'em, they DO act differently from 0 to 9; they must be
good for SOMETHING, but what that something is, I can't figure out.

After all of these questions, I do have ONE nice idiom to offer up:  I
came up with a nice way of getting an identity matrix:

identity =. e. i.

identity 5
1 0 0 0 0
0 1 0 0 0
0 0 1 0 0
0 0 0 1 0
0 0 0 0 1

-- 
Christopher Browne                |     PGP 2.0 key available
cbbrowne@csi.uottawa.ca           |======================================
University of Ottawa              | Genius may have its limitations, but
Master of System Science Program  | stupidity is not thus handicapped.
