[Date Index] [Thread Index] [Author Index]

Re: Checking Programming errors; a ?

• To: mathgroup at smc.vnet.net
• Subject: [mg36672] Re: Checking Programming errors; a ?
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Wed, 18 Sep 2002 02:10:07 -0400 (EDT)
• Organization: Universitaet Leipzig
• References: <alub76$nld$1@smc.vnet.net>
• Reply-to: kuska at informatik.uni-leipzig.de
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

does 
http://www.mathsource.com/Content/Enhancements/FrontEnd/0211-037

help you ?

Regards
  Jens


Jack Goldberg wrote:
> 
> Hi Group:
> 
> I often run into this difficulty:  when designing a program, say as a
> module, and testing it for various inputs, I get wrong answers.  What to
> do?  I use a method that works for me but may not be the best available.
> I want to show my method and then ask a question about how it can be
> imporved.  (Oh yes, I abandoned Trace a long time ago!)
> 
> myFunction[f_] := Module[ {L1,L2,L3},
> 
> L1 = ... ;
> L2 = ... ;
> l3 = ... ;
>         "final step"
> 
>                 ]
> 
> To see what went wrong, I use (*  *) selectively as follows:
> 
> Stage 1
> 
> myFunction[f_] := Module[ {L1,L2,L3},
> 
> L1 = ...  (*;
> L2 = ... ;
> L3 = ... ;
>         "final step" *)
> 
>         ]
> 
> Thus I see if L1 worked as expected.  The next step is to put  (* after L2
> and see if this works.  I continue this til the bitter end and I usually
> find my errors.
> 
> My question;   The process of moving  (*   *)  step by step through the
> program is quite tedious when the code has lots more lines.  What I would
> like is a "meta-program" which (like FoldList) does this job for me.  The
> output of this "meta-program" is the list of outputs of each line in the
> module, probably best printed as a column.
> This sounds like Trace but my problem with Trace is it is terribly
> difficult to read.  For the not-so-subtle programming I do, the only thing
> I need is what expression is returned line by line.
> 
> Any advice?  All remarks are appreciated!
> 
> Jack