Re: Big trouble with Mathematica Code parsing -- Rant.
- To: mathgroup at smc.vnet.net
- Subject: [mg26261] Re: Big trouble with Mathematica Code parsing -- Rant.
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Sun, 10 Dec 2000 00:19:35 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <90kr7d$r49@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
can you send an example notebook/package/code ?
May be that you have forgotten some ";"
between your commands.
like
f[x_] := Module[{y}, If[x > 0, y = 4] x]
will produce
In[]:=f[-2]
Out[]=-2 Null
But the correct definition is
f[x_] := Module[{y}, If[x > 0, y = 4]; x]
Regards
Jens
"Louis M. Pecora" wrote:
>
> [[ This message was both posted and mailed: see
> the "To," "Cc," and "Newsgroups" headers for details. ]]
>
> {\RANT ON}
>
> I have just spent another 3 hours debugging Mathematica code that, for
> some reason unclear to me, insists on putting Null's into the return
> values, as in
>
> 2
> Null Return[{1.0,2.9}] (in which the numbers are right, but the
> Null's don't belong)
>
> Rather than just returning
>
> {1.0,2.9}
>
> Where are they coming from? Beats me. This is the third time in the
> last month or so that I've spent the better part of a day (a few days
> in some cases) trying hard to figure why Mathematica parses my code in
> a brain-dead way.
>
> Beware. Adding white space and blank lines for readability can cause
> Null's to appear and other problems. I suspect this is partly related
> to the fact that space can be taken as a multiplication, but
> eliminating spaces and blank lines may not cure the problem. I know.
> I've tried.
>
> I've done things such as copy the code into a text editor then right
> back to Mathematica and then it works...until I change something or
> open up the file later and try to use it. Then I may get a syntax
> error or just more Nulls, again. Sometimes recopying the code out and
> in will fix it, again. Sometimes not. But what a Kludge!
>
> Mathematica is doing things behind the scenes to the text in its
> parsing and it messes stuff up. Mathematica Support have responded
> with hints such as Set Save in Box Form to False, eliminate white space
> (there goes readability), make sure all lines end in ";" (that one, at
> least, makes sense). I've done it all and still have problems.
>
> It is ridiculous when one of the most powerful sofeware packages in the
> world cannot parse code correctly. It cannot handle simple, clear
> white space correctly. And it insists on changing things which cause
> failures.
>
> These are not feature or even bugs. They are FLAWS.
>
> Maybe it's the automatic indenting. I don't know. I am totally
> frustrated. If anyone knows of anyway to turn off or on some setting
> to get this program to just handle my code sensibly, PLEASE let me
> know.
>
> I hope Wolfram is listening. There is a serious upgrade-FIX needed for
> Mathematica 4.0. Right now I would not recommend this program to
> anyone in my lab.
>
> {\RANT OFF}
>
> My views are my own.