Path: utzoo!utgpu!attcan!uunet!husc6!rutgers!bellcore!clyde!watmath!water!ljdickey
From: ljdickey@water.waterloo.edu (Lee Dickey)
Newsgroups: comp.lang.apl
Subject: Re: debuggers
Message-ID: <1887@water.waterloo.edu>
Date: 14 Oct 88 20:12:38 GMT
References: <109@infbssys.infbs>
Reply-To: ljdickey@water.waterloo.edu (Lee Dickey)
Organization: U. of Waterloo, Ontario
Lines: 58

In article <109@infbssys.infbs> hafer@infbssys.UUCP (Udo Hafermann) writes:
>Could anyone point to references on techniques or systems for
>interactively debugging APL programs?

Dear Udo,

Two books recently mentioned in this news group might be some help:

	APL: an introduction
	1986
	Howard A. Peele
	Hold, Rinehard and Winston
	ISBN 0-03-004953-9


	APL: An Interactive Approach, Third Edition
	1984
	Leonard Gilman and Allen J. Rose
	John Wiley & Sons, Inc
	ISBN 0-471-80585-8


Another book, not for the beginner, is


	APL: Advanced Techniques and Utilities
	1987
	Gary A. Bergquist
	Zark Incorporated, 53 Shenipsit St, Vernon, Connecticut 06066
	ISBN: none?


The two system functions:

	Quad STOP  

can be a big help, because you can stop your function
before it executes any given line and query the variables.
Similarly, you can use

	Quad TRACE  

to print the result value on any line.  

The system command  )SI  can also be a help.
And, of course,  )VARS  sometimes helps.

As to program style, vertical layout of your function will
help you to debug it and read it again after a year has passed.
As a rule of thumb, do not use more than one assignment per line.

OK?

-- 
    L. J. Dickey, Faculty of Mathematics, University of Waterloo.
	ljdickey@WATDCS.UWaterloo.ca	ljdickey@water.BITNET
	ljdickey@water.UUCP		..!uunet!watmath!water!ljdickey
	ljdickey@water.waterloo.edu