Newsgroups: comp.lang.apl
Path: utzoo!utgpu!watserv1!maytag!aftermath!ljdickey
From: ljdickey@aftermath.waterloo.edu (L.J.Dickey)
Subject: What J is  (Was: Where you can order J from)
Organization: University of Waterloo
Date: Thu, 8 Nov 90 14:40:48 GMT
Message-ID: <1990Nov8.144048.12624@aftermath.waterloo.edu>
References: <90290.100040BAKERJ@QUCDN.QueensU.CA> <1990Oct22.220757.28078@water.waterloo.edu> <17000@shlump.nac.dec.com> <1990Nov7.150240.15740@cunixf.cc.columbia.edu>
Lines: 38

In article <1990Nov7.150240.15740@cunixf.cc.columbia.edu> shenkin@cunixf.cc.columbia.edu (Peter S. Shenkin) writes:
>
>I'm a new subscriber to this group;  [...]  and have
>come in in the middle of the discussion of J.  [...] 
>  Can some kind soul either post or mail me a brief description of
>what J is, and how it relates to APL?

J is a dialect of APL that has boxed arrays, complex numbers,
user defined operators, and uses the ascii character set.

It runs on several systems, and the code is intended to be easily
portable from one system to another.

Here is a little bit of code that might begin to show some of the
similarites and some of the changes in J.

   stuff =. 'abcdABCD'
   $ stuff
8
   stuff i. 'aA'
0 4
   n =. i. $stuff
   sum =. +/
   sum n
28
   n sum n
0 1 2  3  4  5  6  7
1 2 3  4  5  6  7  8
2 3 4  5  6  7  8  9
3 4 5  6  7  8  9 10
4 5 6  7  8  9 10 11
5 6 7  8  9 10 11 12
6 7 8  9 10 11 12 13
7 8 9 10 11 12 13 14
   i. 2 3
0 1 2
3 4 5